2008 NEC Review PracticeTest 1 Course Name: 2008 NEC Review Quiz Number: No. 1 Teacher: Gerald Newton Teacher's Home Page: http://www.electrician2.com Teacher's Email:
[email protected]
No. of Questions= 20
1.
In Class 1, Division 1 locations, conduit seals shall be placed a maximum of ______inches from an enclosures containing arc producing equipment. a)
12
b)
18
c)
24
d)
30 18 in. from the enclosure. Only explosionproof unions, couplings, reducers, elbow s, capped elbow s, and conduit bodies such as L, T, and X types not larger than the trade size of the conduit are permitted betw een the sealing fitting and the explosionproof enclosure.
2.
What length is required for the pullbox in the diagram below? The box is used with 480 volt conductors that are not spliced. a)
32 inches
b)
24 inches
c)
48 inches
d)
any length ## CORRECT --> In straight pulls, the length of the box shall not be less than eight times the trade diameter of the largest racew ay. If conductors are spliced the box shall be at least 6 times 2 inches long or 12 inches per 314.28(A)(2)
3.
What is the load that can be used for the service calculation for a dwelling unit when the Range has a nameplate rating of 13 KW? a)
13 kw
b)
8.4 kw
c)
8 kw
d)
none of the above ## CORRECT --> 8 kw + 5 percent of 8 kw is 8.4 kw .
4.
What size copper equipment grounding conductor is required for a circuit protected with a 50 ampere circuit breaker? a)
No. 12 copper
b)
No. 10 copper
c)
No. 8 copper ## CORRECT --> Table 250-122 lists a No. 10 copper for a 50 ampere circuit breaker.
5.
What is the highest voltage permitted for a Class 1 power limited circuit?
a)
1,000 volts
b)
30 volts
c)
24 volts
d)
None of the above ## CORRECT --> Class 1 pow er limited circuits shall be supplied from a source that has a rated output of not more than 30 volts and 1000 volt-amperes.
6.
What is the missing voltage in the sketch below?
a)
120 volts
b)
120 volt's
c)
1200 volts
d)
12,000 volts ## CORRECT --> 120/Voltage = 100 /1000; Voltage = (120 x 1000 )/ 100, Voltage = 1200 volts
7.
What is the minimum size 10 feet long Rigid Metal conduit required for the following 9 conductors? 4 THWN #12 CU, 2 RHW (covered) #8 CU, 3 RHW (covered) #6 CU a)
1 1/2 inch
b)
2 inch
c)
1 1/4 inch
d)
None of the above ## CORRECT -->
8.
What is the efficiency of a motor which draws 4.5 kilowatts from the line and delivers 5 horsepower? a)
80 percent
b)
83 percent
c)
90 percent ## CORRECT --> efficiency = (5 x 746 w atts) / 4,500 w atts
9.
Power Factor can be defined as:
a)
True Power divided by Apparent Power
b)
Apparent Power divided by True Power
c)
Apparent Power divided by volts x amperes ## CORRECT --> True Pow er = w atts, Apparent pow er=volt-amperes. PF = w atts/ volt amperes
10.
What is the power factor for a three phase system operating when the wattmeter reads 6,000 watts, the voltmeter reads 208 volts, and the ammeter reads 20 amperes?
a)
.90 or 90 percent
b)
1.04 or 104 percent
c)
.83 or 83 percent ## CORRECT --> PF = 6,000 / (208*20*1.732)
11.
What is the power factor for a 8000 watt load connected to a 240 volt AC single-phase circuit if the current is 36 amperes? a)
.8 or 80 percent
b)
.93 or 93 percent
c)
1.0 or 100 percent ## CORRECT --> PF = 8,000 / (240 volts x 36 amperes)
12.
For the figure below if No. 4 or larger conductors are installed in the raceways dimension X shall be ____inches minimum. The box is used for splices and doe not have the cubic inch dimensions marked on it. a)
18 inches
b)
16 inches
c)
24 inches ## CORRECT --> Use larger of (6 x 3) + 3 +3 = 24 inches or (6 x 2) + 2 + 1 + 1 = 16 inches. Dimension X shall be 24 inches.
13.
For the 4-way Switch, which is the correct hookup? a)
D to T, E to R, F to T, G to S
b)
D to S, E to R, F to T, G to W
c)
D to R, E to T, F to S, G to W ## CORRECT -->
14.
A dwelling has a floor area of 2200 sq. ft., exclusive of an unfinished cellar not adaptable for future use, unfinished attic, and open porches. Appliances are a 12-kW range and a 5.5-kW, 240-V dryer. Assume range and dryer kW ratings equivalent to kVA ratings in accordance with Sections 220-18 and 220-19.Computed Load [see Section 220-10]
Fill in the following information: General Lighting Load: _____ sq. ft. at __ VA per sq. ft. =_______ VA Minimum Number of Branch Circuits Required: General Lighting Load: ______ VA / 120 V = ___ A General Lighting Load: ______ VA / 120 V = ___ A This requires______ 15-A, 2-wire or______ 20-A, 2-wire circuits Small Appliance Load: _____ 2-wire, 20-A circuits Laundry Load :One 2-wire, 20-A circuit One additional bathroom 20 ampere circuit is also required.
Minimum Size Feeder Required : General Lighting _______ VA Small Appliance ______ VA Laundry ______ VA Total 11100 VA ______ VA at 100% 3000 VA _______ VA - 3000 VA =______ VA at _____% is ______ VA Net Load _______ VA Range ______ VA Dryer________ VA Net Computed Load _______ VA Net Computed Load for 120/240-V, 3-wire, single-phase service or feeder ________ VA / 240 V = ______ A Net computed load exceeds 10 kVA. Would require service conductors to be _____ A. Calculation for Neutral for Feeder and Service: Lighting and Small Appliance Net Load _____ VA Range: _____ VA at 70% is 5600 VA Dryer : _______ VA at 70% is ______ VA Total ________ VA Computed Load for Neutral: __________ VA / 240 V = ______ A
What is the final computed load for the neutral in the above load calculation? a)
65.9
b)
63.7
c)
100
d)
111 ## CORRECT --> see the w eb reference
15.
The correct hookup for the 3-way switch below is:
a)
A to X, B to Z, C to Y
b)
A to Y, B to X, C to Z
c)
A to Z, B to Y, C to X
d)
A to Z, B to X, C to Y ## CORRECT -->
16.
Connect the delta wound 480 volt motor leads for the high voltage windings in the diagram below. a)
9-7, 4-6, 8-9, 5-4
b)
4-7, 5-8, 6-9
c)
4-9, 6-8, 5-7 ## CORRECT -->
17.
Find the correct size ventilated cable tray for the diagram below.
a)
6 inches
b)
12 inches
c)
18 inches
d)
24 inches ## CORRECT --> See the w eb reference.
18.
Find the voltage across the 5 ampere load after the neutral is opened. Both loads are resistive and the power factor is 1.0. a)
180 volts
b)
120 volts
c)
0 volts ## CORRECT --> R for 15 a load = 120/15 = 8 ohms; R for 5 a load = 120/5 = 24; Neutral open I = 240 /(8 + 24) = 7.5 a; E across 5 a load = 7.5 a x 24 = 180 volts
19.
Find the size of inverse time circuit breaker required for the feeder protecting the following polyphase induction motors. These motors are Design B and have a Service Factor of 1.15 and are individually protected with inverse time circuit breakers. a)
150 ampere
b)
175 ampere
c)
200 ampere ## CORRECT --> See the w eb reference
20.
How many cubic inches is required for the following box? All conductors are No. 14 and there are no internal clamps. a)
12 cubic inches
b)
16 cubic inches
c)
18 cubic inches
d)
20 cubic inches ## CORRECT -->
2008 NEC Review PracticeTest 2 Course Name: 2008 NEC Review Quiz Number: No. 2 Teacher: Gerald Newton Teacher's Home Page: http://www.electrician2.com Teacher's Email:
[email protected]
No. of Questions= 20
1.
In the diagram below the total resistance is _____ and the value of R3 is ____.
a)
20, 10.7 ohms
b)
20, 19.7 ohms
c)
20, 20.7 ohms
d)
10, 30 ohms ## CORRECT -->
2.
What is the ampacity of 12 No. 12 THHN copper conductors in a 10 feet long EMT raceway where there are 9 current carrying conductors and the ambient temperature is 42 degree C? (Select nearest answer) a)
10 amperes
b)
15 amperes
c)
18 amperes
d)
22 amperes ## CORRECT --> The derating factor for 9 current carrying conductors in a racew ay is 70 percent, and the ambient derating factor for 42 degrees C. is .87. Ampacity of THHN No. 12 is 30 amperes. .7 x .87 x 30 = 18.27 amperes.
3.
What is the allowable ampacity of each No. 6 THW copper conductor if there are 10 current carrying conductors in a 24 inch long rigid conduit nipple in a room where the ambient temperature is 55 degrees C? (Select nearest answer) a)
65 amperes
b)
67 amperes
c)
50 amperes
d)
44 amperes ## CORRECT --> THW ampacity is 65 amperes. The ambient derating factor is .67 .67 x 65 = 43.55 amperes
4.
Find the size EMT nipple required to enclose 3 each 500 kcmil THHN conductors between two panels. a)
1 1/2 inch
b)
2 inch
c)
3 inch
d)
3 1/2 inch ## CORRECT --> The area for 3 -500 kcmil THHN conductors is 3 x .7073 = 2.1219 For 60 percent fill using the .8 round off method requires a 2 inch EMT.
5.
What size rigid steel conduit is required for 4 each 4/0 XHHW and 1 each No. 3 bare equipment grounding conductor if the raceway is 12 feet long? a)
1 1/2 inch
b)
2 inch
c)
2 1/2 inch
d)
3 inch
e)
1 inch ## CORRECT --> Area of 4 4/0 = 4 x .3197 = 1.2788; area of No. 3 is .053. 1.2788 + .053 = 1.3318 sq. in. requiring a 2 inch rigid conduit w ith a 40 percent area of 1.363 sq. in.
6.
Junction boxes shall be ______.
a)
accessible
b)
readily accessible
c)
visible
d)
inside removable panels ## CORRECT --> Conduit bodies, junction, pull, and outlet boxes shall be installed so that the w iring contained in them can be rendered accessible
7.
The type of lampholder required in a branch circuit in excess of 20 amperes shall be ______. a)
brass
b)
porcelain coated
c)
not an interchangeable type
d)
heavy duty ## CORRECT --> Where connected to a branch circuit having a rating in excess of 20 amperes, lampholders shall be of the heavy-duty type.
8.
Unless an excepted load as specified by the Code, a conductor rated 56 amperes shall be protected by a _____ fuse. a)
50
b)
60
c)
70
d)
80 ## CORRECT --> The next larger size permitted by Code is 60 amperes.
9.
In a washdown area a metallic raceway shall be spaced not less than _____ inch from the walls. a)
1/8
b)
1/4
c)
1/2
d)
3/4 ## CORRECT --> Standard practice is to keep electrical equipment 1/4 inch of the surface in indoor locations that may become w et.
10.
Given: Three (3) 500 kcmil Type THHN copper conductors in a raceway at 70 degrees C. The maximum allowable current in each conductor is _____ amperes.
a)
249
b)
409
c)
430
d)
705 ## CORRECT --> By Table 310-16(bottom) the derating factor for 70 degrees C in the 90 degree C. column is .58. .58 x 430 A. = 249 amperes.
11.
A luminaire (fixture) that weighs more than _______ lb or exceeds 400 mm (16 in.) in any dimension shall not be supported by the screw shell of a lampholder.
a)
4
b)
6
c)
50
d)
70 ## CORRECT --> Luminaires and lampholders shall be securely supported. A luminaire that w eighs more than 6 lb or exceeds 16 in. in any dimension shall not be supported by the screw shell of a lampholder.
12.
An AC-DC general use snap switch may be used with inductive loads at _____ percent of its ampere rating at the applied voltage.
a)
40
b)
50
c)
70
d)
80 ## CORRECT --> A form of general-use snap sw itch suitable for use on either ac or dc circuits for controlling Inductive loads not exceeding 50 percent of the ampere rating of the sw itch.
13.
When utilized as outside branch circuits and feeders, overhead conductors for 600 volts or less, for spans up to 50 feet, shall not be less than _____ copper.
a)
No. 14
b)
No. 12
c)
No. 10
d)
No. 8 ## CORRECT --> Open individual conductors shall not be smaller than the follow ing: For 600 volts, nominal, or less, No. 10 copper or No. 8 aluminum for spans up to 50 ft (15.2 m) in length and No. 8 copper or No. 6 aluminum for a longer span, unless supported.
14.
Conductors of light and power systems of 600 volts or less may occupy the same enclosure, without regard to whether the individual circuits are AC or DC, only where all the conductors are ________. a)
insulated for the maximum temperature within the enclosure.
b)
insulated for the maximum voltage applied to any conductor within the enclosure
c)
insulated for the maximum of 300 volts
d)
none of the above ## CORRECT --> seccion 303.3(c)(1)
15.
When utilized in overhead services, without any exceptions, conductors shall not be smaller than No. ______ copper.
a)
14
b)
12
c)
10
d)
8 ## CORRECT --> The conductors shall not be smaller than No. 8 copper or No. 6 aluminum or copper-clad aluminum.
16.
Made electrodes shall have a resistance to ground not to exceed ______ ohms when used alone.
a)
5
b)
10
c)
25
d)
30 ## CORRECT --> A single electrode consisting of a rod, pipe, or plate that does not have a resistance to ground of 25 ohms or less shall be augmented by one additional electrode of any of the types specified in Sections 250-52(A)(4) through (A)(8).
17.
Disregarding all exceptions, the sum of the cross-sectional area of all conductors in a metal wireway shall not exceed ______ percent of the interior cross-sectional area of the wireway. a)
20
b)
30
c)
40
d)
60
## CORRECT --> The sum of cross-sectional areas of all contained conductors at any cross section of the w irew ay shall not exceed 20 percent of the interior cross-sectional area of the w irew ay.
18.
Given: Nine (9) No. 8 AWG THHN copper conductors in a conduit at 30 degrees C. What is the maximum allowable ampacity in each conductor?
a)
33.3
b)
38.5
c)
40.0
d)
55 ## CORRECT --> By Table 310.15(b)(2)(a) the derating factor for 9 conductors in a racew ay is 70%. .70 x 55 = 38.5 amperes.
19.
The minimum total circuit ampacity required to supply an air conditioning motor compressor unit which consumes 8,500 volt amperes of power at a line voltage of 240 volts is ______ amperes. Select the closest answer. a)
44.3
b)
40.0
c)
35.4
d)
28.3 ## CORRECT --> I = P/E = 8500 VA/ 240 volts = 35.4 amperes. From Table 440.32 125 per cent of 35.4 = 44.3 amperes.
20.
Given: An office building has a required general lighting load of 50,000 volt amperes. The general lighting load is supplied by a single phase, 230 volt feeder circuit. The
minimum calculated current in the feeder circuit ungrounded (hot) conductors is _____ amperes. Select the closest answer. a)
208
b)
217
c)
227
d)
230 ## CORRECT --> I = P / E; 50,000 / 240 volts = 208 amperes.
2008 NEC Review Practice Test 3 Course Name: 2008 NEC Review Quiz Number: No. 3 Teacher: Gerald Newton Teacher's Home Page: http://www.electrician2.com Teacher's Email:
[email protected] No. of Questions= 20
1. Given: Three (3) 500 kcmil THHN conductors in a raceway at 70 degrees F. What is the maximum allowable current in each conductor if the terminations and equipment is rated at 90 Degrees C?
a)
345
b)
380
c)
430
d)
447
## CORRECT --> The correction factor at the bottom of Table 310-16 for 70 degrees F.is 1.04 for 90 degree rated insulation such as THHN. 1.04 x 430 amperes = 447amperes.
2. Flexible cord may be used in all of the following locations except ______.
a)
hoists
b)
cranes
c)
to replace fixed wiring of a structure
d)
pendants
## CORRECT -->
3. When a conduit nipple having a maximum length not to exceed 24 inches is installed, the nipple shall be permitted to be filled to _____ percent of its total cross sectional area.
a)
30
b)
40
c)
50
d)
60
## CORRECT --> Where conduit or tubing nipples having a maximum length not to exceed 24 in. (610 mm) are installed betw een boxes, cabinets, and similar enclosures, the nipples shall be permitted to be filled to 60 percent of their total cross-sectional area.
4. Drums of gasoline may be stored in what type of outdoor area?
a)
Anywhere
b)
Class III, Division 2
c)
Class II, Division 1
d)
Unclassified areas at a bulk storage plants.
## CORRECT --> This permission is given for bulk storage plants in Table 515.3
5. The interior of paint spray booths are considered ______.
a)
Class 1, or Class 2, Division 1
b)
Class 1, Division 2
c)
Class II, Division 2
d)
Class II, Division 2
## CORRECT --> The follow ing spaces shall be considered Class I or Class II, Division 1 locations, as applicable: The interiors of spray booths and rooms.
6. The maximum allowable fill for conduit and tubing for 3 or more conductors, not lead covered is _______.
a)
30%
b)
40%
c)
50%
d)
60%
## CORRECT --> By Table 1 in Chapter 9, 40 percent.
7. In a conduit seal used in hazardous locations, the minimum thickness of the sealing compound, except where used in cables, should in no case be less than _______.
a)
1/4"
b)
1/2"
c)
5/8"
d)
3/4"
## CORRECT --> In a completed seal, the minimum thickness of the sealing compound shall not be less than the trade size of the sealing fitting and, in no case, less than 5/8 in.
8. Given: A 30 hp, 3-phase, 460 volt, continuous duty induction motor with a service factor of 1.15 and a temperature rise of 40 degrees C. The maximum rating of the required separate overload device is ______ amperes.
a)
46
b)
50
c)
56
d)
60
## CORRECT --> 125 percent of 40 is 50 amperes, but Section 430.32 allow s a 140 percent maximum overload.
9. Given: Measurements for a 3-phase squirrel cage motor at full load are 460 volts and 65 amperes. Approximate the horsepower rating using the Code?
a)
30
b)
40
c)
50
d)
60
## CORRECT --> By Table 430.150 a 50 horsepow er motor has a full load amperes of 65.
10.
Refer to the figure below. Given the circuit shown. What is the current in the neutral conductor?
a)
25.0 amperes
b)
12.5 amperes
c)
6.25 amperes
d)
4.2 amperes
## CORRECT --> Current through 1000 w att load = 1,000/120 =8.3 amperes; Current through 500 w att load = 500/120 = 4.17 amperes. 8.3 - 4.1 = 4.2 amperes.
11. Given: A 25 foot feeder tap. The ampacity of the tap must be at least ____ that of the feeder conductor or overcurrent protection from which it is tapped.
a)
1/4
b)
1/3
c)
1/2
d)
3/4
## CORRECT --> Also, the tap conductors shall terminate in a single circuit breaker or a single set of fuses that w ill limit the load to the ampacity of the tap conductors and shall be protected.
12. The normal current allowed on a copper bus in an Auxiliary Gutters is 1,000 amperes per square inch. The number of amperes which a 2 1/2 x 1/4 inch square copper bus may carry under these
conditions is _____ amperes.
a)
625
b)
750
c)
1,000
d)
1,250
## CORRECT --> Amperes = (2.5 x .25) x 1,000= 625 amperes
13. Given: A 240 volt conductor has a total length of 500 feet and supplies a load of 10 amperes. The conductor has a resistance of 1.45 ohms per 1,000 feet. The total voltage drop in the conductor circuit conductors is _____ percent. Select the closest answer.
a)
3
b)
5
c)
7
d)
12
## CORRECT --> E=IxR; E=10 x (500/1,000)x 1.45 = 7.25 volts; percent =(7.25/240 ) x 100 = 3 percent
14. The maximum fixture weight that may be supported by the screw shell of a lampholder is _____ pounds.
a)
2
b)
6
c)
10
d)
16
## CORRECT --> A fixture that w eighs more than 6 lb (2.72 kg) or exceeds 16 in. (406 mm) in any dimension shall not be supported by the screw shell of a lampholder.
15. Where a cable is installed through bored holes in wood joists, where possible, the holes shall be bored so that the edge of the hole is not less than ______ inch(es) from the nearest edge of the wood member.
a)
1
b)
1 1/4
c)
1 1/2
d)
2
## CORRECT --> If this requirement cannot be met, listed *nail plates* can be used.
16. The minimum lighting load required for the general lighting (only) of a church building having outside dimensions of 100' by 200' is ______ volt-amperes.
a)
2,000
b)
4,000
c)
20,000
d)
40,000
## CORRECT --> 100` x 200` = 20,000 sq. ft.,By Table 220.12 1 VA per square foot is required for churches. 1 x 20,000 =20,000 VA.
17. The minimum size copper equipment grounding conduct for grounding equipment having a 40 ampere automatic overcurrent device in the circuit ahead of the equipment is No. _____.
a)
6
b)
8
c)
10
d)
12
## CORRECT --> By Table 250-122 a 40 ampere OCPD requires a No. 10 copper equipment grounding conductor.
18. Given: A 240 volt, 20 ampere two wire branch circuit. If the maximum allowable voltage drop through the circuit conductors is 2.4 volts, what is the maximum allowable resistance of the circuit conductors?
a)
12 ohms
b)
1.2 ohms
c)
0.48 ohms
d)
0.12 ohms
## CORRECT --> R= E/ I; R= 2.4/ 20; R = .12 ohms. The 240 volts is used for calculating percent voltage drop w hich in this case is (2.4/240 )x 100 = 1 percent.
19. The combined load of two, 230 volt fixed heaters on a 30 ampere 230 volt branch circuit in a dwelling occupancy shall not exceed _____ kilowatts. Select the closest answer.
a)
2.4
b)
5.5
c)
5.9
d)
24.0
## CORRECT --> .8 x 30 = 24 amperes. 24 x 230 = 5520 w atts; 5520/1000= 5.5 kw .
20. Outlet boxes mounted in combustible walls or ceilings must be mounted so that they will be set back not more than a maximum of _____ inch from the finished surface.
a)
1/2
b)
1/4
c)
1/8
d)
0 (must be flush or project therefrom)
## CORRECT --> In w alls and ceilings constructed of w ood or other combustible material, boxes shall be flush w ith the finished surface or project there from.
2008 NEC Review Practice Test 4 Course Name: 2008 NEC Review Quiz Number: No. 4 Teacher: Gerald newton Teacher's Home Page: http://www.electrician2.com Teacher's Email:
[email protected]
No. of Questions= 20
Refer to the figure below. What is wrong with the grounding rod installation illustrated below (Assume the rod could not be driven because of a a rock bottom)?
1. a)
It is not 10 feet long.
b)
The ground rod shall be 5/8 inches in diameter
c)
It is not 30 inches deep
d)
There is nothing wrong, according to the Code ## CORRECT --> Where rock bottom is encountered, the electrode shall be driven at an oblique angle not to exceed 45 degrees from the vertical or shall be buried in a trench that is at least 2½ ft (762 mm) deep.
2.
Which of the following is not a standard fuse or inverse time circuit breaker size? a)
35
b)
45
c)
50
d)
55 ## CORRECT --> 50 amperes and 60 amperes are standard fuse and circuit breaker sizes but 55 is not.
In general, a continuous duty motor rated at more than 1 horsepower shall be protected by a separate overload device rated at no more than ______ percent of the motor nameplate full-load current rating.
3. a)
75
b)
100
c)
115
d)
125 ## CORRECT -->
Where direct buried conductors or cables emerge from the ground they shall be protected by enclosures or raceways. In no case shall the protection be required to exceed ______ inches below finished grade.
4. a)
12
b)
18
c)
24
d)
30 ## CORRECT --> Direct-buried conductors and cables emerging from the ground shall be protected by to a point at least 8 ft above finished grade. In no case shall the protection be required to exceed 18 in. below ground.
Given: Three resistors (R1, R2, and R3) are installed in a series circuit. The power used by R1 is 100 watts and the power used by R2 is 75 watts. The total power used by the circuit is 225 watts. Then the power used by resistor R3 is _____ watts.
5. a)
24
b)
50
c)
75
d)
175 ## CORRECT --> 225 - 75 - 100 = 50 w atts
Refer to the figure below. The total resistance Rt is ______ ohms. Select the closest answer.
6. a)
9.4
b)
10.5
c)
15
d)
40 ## CORRECT --> Basic electrical theory. Rt = (R1 x R2)/ (R1 + R2); RT = (25 x 15) / (25 +15) = 9.4 ohms
Given: A free standing electric range is rated 120/240 volts and requires a neutral connection for the 120 volt timer and lights. The range is equipped with 3 wire cord with No. 8 copper conductors and a 3 prone plug for two hot leads and neutral. The range frame shall be permitted to be _______.
7.
a)
grounded by running a ground from the range frame to the outlet box, wrapping the ground around the cord and then grounding it to the outlet box.
b)
ungrounded
c)
grounded by a 4-wire cord containing the two hot leads, the neutral, and a green grounding conductor. (the range requires a 4-wire cord)
d)
grounded at the range by bonding the grounded conductor to the range frame.
## CORRECT --> A new change no longer allow s ranges to be grounded w ith he grounded conductor in new installations.
In dwelling units a multi-wire branch circuit supplying more than one device on the same yoke shall be protected by _______.
8. a)
two (2) single pole circuit breakers, operating independently
b)
two (2) single pole circuit breakers, tied together
c)
one (1) non-fused single pole disconnect only
d)
one (1) fuse only ## CORRECT --> In dw elling units, a multiw ire branch circuit supplying more than one device or equipment on the same yoke shall be provided w ith a means to disconnect simultaneously all ungrounded conductors at the panelboard w here the branch circuit originated.
The Code requires at least two small appliance branch circuits for dwellings. These small appliance circuits shall be assigned a load of _______ volt-amperes each when calculating feeders and service entrance requirements.
9. a)
750
b)
1000
c)
1500
d)
2000 ## CORRECT --> In each dw elling unit, the load shall be computed at 1500 volt-amperes for each 2-w ire smallappliance branch circuit required by Sections 210.11(C) (1) and 220.52(A)
10.
Which of the following receptacles may be connected to the small appliance circuits?
a)
receptacles for electric clocks in the kitchen
b)
garage ceiling receptacles for garage door openers
c)
hallway receptacles which are close to the kitchen
d)
living room receptacles
## CORRECT --> Also the small appliance branch circuits can supply Receptacles installed to provide pow er for supplemental equipment and lighting on gasfired ranges, ovens, or counter-mounted cooking units.
11.
A metal underground water pipe in direct contact with the earth for at least 10 feet has traditionally been a preferred grounding electrode. For all new construction, a metal underground water pipe is _______.
a)
still the preferred grounding electrode, by itself, when available.
b)
still an acceptable grounding electrode, but it must be supplemented by at least one additional grounding electrode.
c)
no longer accepted as a grounding electrode
d)
accepted as the only grounding electrode when buried at least three(3) feet below the surface. ## CORRECT --> Because plumbers keep replacing metal pipe w ith plastic pipe the metal underground w ater pipe is no longer a reliable underground grounding electrode.
12.
Thermal insulation shall not be installed within _____ inches of a recessed light fixture enclosure unless the recessed light fixture is identified as suitable for direct contact with insulation.
a)
2
b)
3
c)
4
d)
5 ## CORRECT --> Thermal insulation shall not be installed above a recessed fixture or w ithin 3 in. (76 mm) of the recessed fixture*s enclosure, w iring compartment, or ballast unless it is identified for contact w ith insulation, Type IC.
13.
The No. 12 or 14 grounded conductor of a branch circuit shall be identified by a ______ wire.
a)
white or gray color or three continuous white stripes on other than green insulation.
b)
green color or bare copper
c)
yellow color
d)
black color ## CORRECT --> An insulated grounded conductor of No. 6 or smaller shall be identified by a continuous w hite or natural gray outer finish or by three continuous w hite stripes on other than green insulation along its entire length.
14.
The Code defines "continuous load" as a load where the maximum current is expected to continue for at least _______.
a)
one hour or more
b)
two hours or more
c)
three hours or more
d)
twenty four hours a day ## CORRECT --> Continuous Load: A load w here the maximum current is expected to continue for 3 hours or more.
15.
For calculating the maximum number of conductors allowed in an outlet box the volume required for each No. 12 conductor is _____ cubic inches.
a)
2
b)
2.25
c)
2.5
d)
3 ## CORRECT --> No. 2 requires 2.25 cubic inches per Table 314.16(B)
16.
Outlet boxes mounted in non-combustible walls or ceilings must be mounted so that they will be set back not more than a maximum of _____ inch from the finished surface.
a)
1/8
b)
1/4
c)
1/2
d)
3/4 ## CORRECT --> section 314.20
17.
Screw-shell lampholders shall be wired so that the ______ conductor is connected to the screw-shell.
a)
grounding
b)
grounded
c)
ungrounded
d)
bare ## CORRECT --> For devices w ith screw shells, the terminal for the grounded conductor shall be the one connected to the screw shell.
18.
Metal enclosures for overcurrent devices in damp or wet locations shall be mounted so there is at least ______ inch air space between the wall or other support surface.
a)
1/8
b)
1/4
c)
3/8
d)
1/2 ## CORRECT --> section 240.32 and 312.2
19.
Are least ______ inches of free conductor shall be left at each outlet and switch point for splices or for the connection of fixtures or devices.
a)
5
b)
6
c)
7
d)
8 ## CORRECT --> At least 6 in. (152 mm) of free conductor, measured from the point in the box w here it emerges from its racew ay or cable sheath, shall be left at each outlet, junction, and sw itch point for splices or the connection of fixtures or devices. section 300.14
20.
In determining load on the volt-ampere per square foot basis the _______the building shall be used for each floor.
a)
outside dimensions of
b)
inside dimensions of
c)
height of
d)
number of rooms in ## CORRECT --> The floor area for each floor shall be computed from the outside dimensions of the building, dw elling unit, or other area involved.section 220.12
Basic Electrical Theory in a Nutshell by electrician.com
Series Direct Current Circuit Rules
Rule #1: The same current flows through each part of a series circuit. Rule #2: Total Resistance of a series circuit is equal to the sum of the individual resistances. Rule #3: The total voltage across a series circuit is equal to the sum of the individual voltage drops. Rule #4: The voltage drop across a resistor in a series circuit is proportional to the size of the resistor.
Rule #5: The total power dissipated in a series circuit is equal to the sum of the individual power dissapations. SUMMARY OF OHMS LAW FORMULAS AMPERES =
RESISTANCE =
VOLTS RESISTANCE VOLTS AMPERES
VOLTS = AMPERES x RESISTANCE
Parallel Direct Current Circuit Rules
Rule #1: The same voltage exists across each branch of a parallel circuit and is equal to the source voltage. Rule #2: The current through a branch of a parallel network is inversely proportional to the amount of resistance of the branch. Rule #3: The total current of a parallel circuit is equal to the sum of the currents of the individual branches of the circuit. Rule #4: The total resistance of a parallel circuit is equal to the reciprocal of the sum of the reciprocals of the individual resistances of the circuit. Rule #5: The total power dissipated in a parallel circuit is equal to the sum of the individual power dissapations.
SUMMARY OF PARALLEL CIRCUIT RULES TOTAL VOLTAGE = E(1) = E(2) = E(3) ...etc. TOTAL RESISTANCE =
VOLTS AMPERES
TOTAL VOLTAGE VOLTS = TOTAL AMPERES
TO DETERMINE THE TOTAL RESISTANCE IN A PARALLEL CIRCUIT WHEN THE TOTAL CURRENT AND TOTAL VOLTAGE ARE UNKNOWN USE EITHER OF THE FOLLOWING FORMULAS:
RT
=
1 ___________________ 1 + 1 + 1 + ......etc R1 R2 R3
FOR TWO RESISTORS IN PARALLEL USE THIS FORMULA CALLED THE "PRODUCT OVER THE SUM" RT =
R(1) * R(2) R(1) + R(2)
POWER IN SINGLE PHASE RESISTIVE CIRCUITS WHERE POWER FACTOR IS 100 PERCENT (THESE
FORMULAS ARE COMMONLY USED TO SOLVE MOST CIRCUIT POWER PROBLEMS ON TESTS)
TO DETERMINE THE POWER CONSUMED BY AN INDIVIDUAL RESISTOR IN A SERIES CIRCUIT USE THIS FORMULA:
POWER
=
I2 x R
TO DETERMINE THE POWER CONSUMED BY AN INDIVIDUAL RESISTOR IN A PARALLEL CIRCUIT USE THIS FORMULA:
POWER
=
E2 R
TO DETERMINE THE TOTAL POWER CONSUMED BY AN INDIVIDUAL CIRCUIT USE THIS FORMULA: POWER
= E (TOTAL VOLTAGE)
x I (TOTAL CURRENT)
RULES OF THUMB:
THE TOTAL RESISTANCE OF RESISTORS IN PARALLEL IS ALWAYS LESS THAN THE VALUE OF ANY ONE RESISTOR.
THE TOTAL RESISTANCE OF PARALLEL RESISTORS THAT ARE ALL THE SAME VALUE IS THAT VALUE DIVIDED BY THE NUMBER OF RESISTORS.
ALWAYS USE THE PRODUCT OVER SUM RULE TO BREAK DOWN TWO PARALLEL RESISTORS INTO ONE RESISTOR.
THIS IS MUCH EASIER
THAN TRYING TO SOLVE LARGE ALGEBRAIC EXPRESSIONS.
746 WATTS IS EQUAL TO ONE HORSEPOWER
EFFICIENCY IS EQUAL TO OUTPUT DIVIDED BY INPUT
IN INDUCTIVE CIRCUITS CURRENT LAGS VOLTAGE.
IN CAPACITIVE CIRCUITS CURRENT LEADS VOLTAGE.
POWER FACTOR IS A MEASURE OF HOW FAR CURRENT LEADS OR LAGS VOLTAGE.
POWER IN ALTERNATING CURRENT CIRCUITS WHERE POWER FACTOR IS NOT 100 PERCENT POWER = E x I x POWER FACTOR (FOR
SINGLE PHASE)
POWER = E x I x 1.732 X POWER FACTOR (FOR
THREE PHASE)
THIS POWER IS ALSO CALLED TRUE POWER OR REAL POWER AS OPPOSED TO APPARENT POWER FOUND BY CALCULATING VOLT-AMPERES. VOLT-AMPERES = E x I (FOR
SINGLE PHASE)
VOLT-AMPERES = E x I x 1.732 (FOR
THREE PHASE)
IT CAN READILY BE DETERMINED BY ALGEBRA THAT
POWER FACTOR
=
TRUE POWER APPARENT POWER
MOTOR APPLICATION FORMULAS
HORSEPOWER = 1.732 x VOLTS x AMPERES x EFFICIENCY x (for three phasefactor 746 motors) THREE PHASE AMPERES = (for three phase motors)
746 x HORSEPOWER 1.732 x VOLTS x EFFICIENCY x POWER FACTOR
SYNCHRONOUS RPM
=
HERTZ x 120 NUMBER OF POLES
MOTOR MARKINGS AND CONNECTIONS CONNECTIONS FOR NINE LEAD THREE PHASE MOTORS
power
THREE PHASE STAR OR Y
Voltage
Line 1
STAR CONNECTED Line 2 Line 3
Low
1&7
2&8
3&9
4&5&6
High
1
2
3
4 & 7, 5 & 8, 6 & 9
THREE PHASE DELTA
Together
DELTA CONNECTED Line 2 Line 3
Voltage
Line 1
Low
1&6&7
2&4&8
3&5&9
NONE
High
1
2
3
4 & 7, 5 & 8, 6 & 9
DELTA WYE HOOKUP FOR TRANSFORMER
MOTOR CONTROLLER WITH THREE START STOP STATIONS (HOLDING CONTACTS NOT SHOWN)
Together
TRANSFORMER TURNS RATIO
Ep
=
Tp
Es
Ts
Where Ep is primary voltage Es is secondary voltage Tp is number of turns in primary Ts is number of turns in secondary
Maximum Horsepower for NEMA-Rated Motor Starters Single-Phase NEMA 115 Size Volt
Three-Phase
230 Volt
208/230 460/575 Volt Volt
00
1/3
1
1.5
2
0
1
2
3
5
1
2
3
7.5
10
2
3
7.5
10/15
25
3
25/30
50
4
40/50
100
5
75/100
200
NEMA RATING FOR ENCLOSURES NEMA and other organizations have established standards of enclosure construction for control equipment. In general, equipment would be enclosed for one or more of the following reasons:
1. Prevent accidental contact with live parts. 2. Protect the control from harmful environmental conditions. 3. Prevent explosion or fires which might result from the electrical arc caused by the control. Common types of enclosures per NEMA classification numbers are: NEMA I - GENERAL PURPOSE The general purpose enclosure is intended primarily to prevent accidental contact with the enclosed apparatus. It is suitable for general purpose applications indoors where it is not exposed to unusual service conditions. A NEMA I enclosure serves as protection against dust and light indirect splashing, but is not dusttight. NEMA 3 - DUSTTIGHT, RAINTIGHT This enclosure is intended to provide suitable protection against specified weather hazards. A NEMA 3 enclosure is suitable for application outdoors, on ship docks, canal and construction work, and for application in subways and tunnels. It is also sleet-resistant. NEMA 3R - RAINPROOF, SLEET RESISTANT This enclosure protects against interference in operation of the contained equipment due to rain, and resists damage from exposure to sleet. It is designed with conduit hubs and external mounting, as well as drainage provisions. NEMA 4 - WATERTIGHT A watertight enclosure is designed to meet the hose test described in the following note: "Enclosures shall be tested by subjection to a stream of water. A hose with a one inch nozzle shall be used and shall deliver at least 65 gallons per minute. The water shall be directed on the enclosure from a distance of not less than 10 feet and for a period of five minutes. During this period it may be directed in any one or more directions as desired. There shall be no leakage of water into the enclosure under these conditions." A NEMA 4 enclosure is suitable for applications outdoors on ship docks and in dairies, breweries, etc. NEMA 4X - WATERTIGHT, CORROSION-RESISTANT These enclosures are generally constructed along the lines of NEMA 4 enclosures except they are made of a material that is highly resistant to corrosion. For this reason, they are ideal in applications such as
paper mills, meat packing, fertilizer and chemical plants where contaminants would ordinarily destroy a steel enclosure over a period of time. NEMA 7 - HAZARDOUS LOCATIONS - CLASS I These enclosures are designed to meet the application requirements of the National Electrical Code for Class I hazardous locations. In this type of equipment, the circuit interruption occurs in air. "Class I locations are those in which flammable gases or vapors are or may be present in the air in quantities sufficient to produce explosive or ignitable mixtures." NEMA 9 HAZARDOUS LOCATIONS - CLASS II These enclosures are designed to meet the application requirements of the National Electrical Code for Class II hazardous locations. "Class II locations are those which are hazardous because of the presence of combustible dust." The letter or letters following the type number indicates the particular group or groups of hazardous locations (as defined in the National Electrical Code) for which the enclosure is designed. The designation is incomplete without a suffix letter or letters. NEMA 12 - INDUSTRIAL USE The NEMA 12 enclosure is designed for use in those industries where it is desired to exclude such materials as dust, lint, fibers and flyings, oil see page or coolant see page. There are no conduit openings or knockouts in the enclosure, and mounting is by means of flanges or mounting feet. NEMA 13 - OILTIGHT, DUSTTIGHT NEMA 13 enclosures are generally of cast construction, gasketed to permit use in the same environments as NEMA 12 devices. The essential difference is that, due to its cast housing, a conduit entry is provided as an integral part of the NEMA 13 enclosure, and mounting is by means of blind holes, rather than mounting brackets.
2008 NEC Review Practice Test 5 Course Name: 2008 NEC Review Quiz Number: No. 5 Teacher: Gerald Newton Teacher's Home Page: http://www.electrician2.com Teacher's Email:
[email protected]
No. of Questions= 20
1.
The circuit conductor that is defined as being intentionally grounded is the _______ conductor.
a)
grounding
b)
grounded
c)
equipment grounding
d)
grounding electrode ## CORRECT --> Grounded Conductor. A system or circuit conductor that is intentionally grounded.
Class II location are those that are hazardous because of the presence of ________.
2. a)
ignitable vapors
b)
ignitable fibers
c)
combustible dust
d)
combustible liquids section 500.6(b)## CORRECT --> Class II locations are those that are hazardous because of the presence of combustible dust.
If three resistors with values 5, 10, and 15 ohms respectively are connected in parallel, the combined total resistance is ____ ohms. Select the closest answer.
3. a)
0.4
b)
2.3
c)
2.7
d)
30.0 ## CORRECT --> For the 5 and 10: (5 x 10) / (5 + 10)= 3.3: 3 in parallel w ith 15 is (15 x 3.3) / 15 + 3.3) = 2.7 ohms
The wiring in a 200 foot long branch circuit measures a total resistance of 0.5 ohms. What is the resistance per 1,000 feet?
4. a)
0.5 ohms
b)
1.0 ohms
c)
2.5 ohms
d)
5.0 ohms ## CORRECT --> 1000 is 5 times 200 so resistance is 5 x .5 = 2.5 ohms
The maximum total voltage drop on both feeders and branch circuits to the farthest outlet should not exceed ____ percent of the supply voltage.
5. a)
2
b)
3
c)
4
d)
5 ## CORRECT --> 5 percent total: 2 percent for feeders or 3 percent for branch circuits.section 210.19(a)(1)FPN #4;215.2(A)(3)FPN #2
The working space in front of enclosed equipment operating at a voltage of 480 volts must have a width of a least ______ inches.
6. a)
42
b)
30
c)
36
d)
20 ## CORRECT --> See the hint.SECTION 110.26(A)(2)
For dwelling units, the Code requires a minimum of _______ for the kitchen small appliance load.
7. a)
one 15 ampere
b)
two 15 ampere circuits
c)
one 20 ampere circuit
d)
two 20 ampere circuits ## CORRECT --> In addition to the number of branch circuits required by other parts of this section, tw o or more 20-ampere small-appliance branch circuits shall be provided.SECTION 210.11(C)(1)
Generally, equipment grounding conductors No. 6 and smaller shall be identified by ______. (select best answer)
8. a)
green color unless it is bare
b)
green color with one or more yellow stripes unless it is bare
c)
bare conductor
d)
bare or Individually covered or insulated equipment grounding conductors shall have a continuous outer finish that is either green or green with one or more yellow stripes except as permitted in this section.
e)
All of the above ## CORRECT --> SECTION 250.119
Rod and pipe grounding electrodes shall not be less than ____ feet in length.
9. a)
6
b)
7
c)
8
d)
10 ## CORRECT --> Rod and pipe electrodes shall not be less than 8 ft (2.44 m) in length.SECTION 250.52(A)(5)
10.
Every dining room of a dwelling unit requires receptacle outlets to be installed so that no point along the floor line in any wall space more than _____ feet, measured horizontally, from an outlet.
a)
6
b)
7
c)
8
d)
10 ## CORRECT --> In every kitchen, family, dining, recreation, living room, parlor, library, den, sunroom, bedroom, receptacle outlets shall be installed so that no point along the floor line in any w all space is more than 6 feet from an receptacle. SECTION 210.52(A)(1)
11.
Open runs of Listed liquidtight flexible nonmetallic conduit installed in lengths longer then ____ feet shall be secured every ____ feet.
a)
6, 3
b)
6, 4 1/2
c)
6, 66
d)
10, 10 ## CORRECT --> SECT.356.30
12.
Generally, noncurrent-carrying metal parts of electrical equipment should be kept at least ____ feet away from lightning rod conductors in air and 3 feet from lightning conductors in concrete, or shall be bonded to the lightning conductors.
a)
3
b)
4
c)
5
d)
6 ## CORRECT --> Separation from lightning protection conductors is typically 6 ft (1.83 m) through air or 3 ft (0.92 m) through dense materials such as concrete, brick, or w ood.SECTION 250.106FPN #2
13.
Branch-circuit conductors supplying a single motor which operates under continuous duty shall have an ampacity not less than ____ percent of the motor full-load current rating.
a)
100
b)
115
c)
125
d)
140 ## CORRECT --> Branch-circuit conductors that supply a single motor used in a continuous duty application shall have an ampacity of not less than 125 percent of the motor’s full-load current rating as determined by Section 430.6(A).
14.
The maximum number of overcurrent devices (other than those provided in the mains) in a single cabinet of a lighting and appliance panelboard ___________ . (select the best answer)
a)
is 30
b)
is 36
c)
is no longer limited. The quantity of overcurrent devices is limited to design and listing of the panelboard.
d)
is 42 ## CORRECT --> Aside from the second exception to 408.36, the maximum of 42 overcurrent devices w as deleted for the 2008 Code. Now the quantity of overcurrent devices is limited to design and listing of the panelboard.SECTION 408.54
15.
Where a branch circuit supplies continuous loads or any combination of continuous and noncontinuous loads, the minimum branch-circuit conductor size, before the application of any adjustment or correction factors, shall have an allowable ampacity not less than the noncontinuous load plus ______ percent of the continuous load.
a)
65
b)
80
c)
125
d)
200 ## CORRECT --> SECTION 210.19(A)(1)
16. a)
Liquid-tight flexible metal conduit may be used in _____. areas that are both exposed and concealed
b)
areas that are subject to physical damage
c)
4 1/2 inch trade size
d)
5 inch trade size ## CORRECT --> SECTION 350.10 & 350.12
17.
The maximum size of flexible metallic tubing that may be used in any construction or installation is _____.
a)
3/8"
b)
1/2"
c)
3/4"
d)
1" ## CORRECT --> This seems very small, but it is w hat the Code says. The Minimum Bend Radii is 17 1/2 inches! SEECTION 360.20(B)
18.
Where conductors of less than 600 volts emerge from the ground they shall be protected by enclosures or raceways that extend from below grade to a point at least ____ feet above finished grade.
a)
4
b)
6
c)
8
d)
10 ## CORRECT --> SECTION 300.5(D)(1)
19.
The total number of quarter bends allowed in one run of rigid nonmetallic conduit shall not exceed ____.
a)
2
b)
3
c)
4
d)
5 ## CORRECT --> SECTION 352.26
20.
Where ungrounded conductors of minimum size No. _____ or larger enter a raceway in a cabinet, the conductors shall be protected by an insulated fitting.
a)
3
b)
4
c)
6
d)
5 ## CORRECT --> Where racew ays containing ungrounded conductors No. 4 or larger enter a cabinet, box enclosure, or racew ay, the conductors shall be protected.SECTION 300.4(G)
2008 NEC Review Practice Test 6 Course Name: 2008 NEC Review Quiz Number: No. 6 Teacher: Gerald Newton Teacher's Home Page: http://www.electrician2.com Teacher's Email:
[email protected]
No. of Questions= 20
Fountains that have water common to a swimming pool do not need to comply with all of the swimming pool requirements.
1. a)
True
b)
False
## CORRECT --> SECTION 680.50
At swimming pools an intentional bond of a minimum conductive surface area of 9 square inches shall be installed in contact with the pool water. This bond shall be permitted to consist of parts that are required to be bonded in 680.26(B).
2.
a)
True
b)
False ## CORRECT --> 680.26(C)
Metal parts of forming shells for Wet-Niche swimming pool luminaires in contact with pool water are not permitted to be made of brass.
3. a)
True
b)
False ## CORRECT --> 680.23(B)(1)
The minimum depth for any underwater lighting fixture is 18 inches below water unless listed otherwise.
4. a)
True
b)
False ## CORRECT --> Wall-Mounted Luminaires (Fixtures). Luminaires (lighting fixtures) mounted in w alls shall be installed w ith the top of the luminaire (fixture) lens not less than 450 mm (18 in.) below the normal w ater level of the pool, unless the luminaire (lighting fixture) is listed and identified for use at lesser depths. No luminaire
GFCI protection is required for any branch circuit that supplies underwater fixtures operating at over 15-volts.
5. a)
True
b)
False ## CORRECT --> ground-fault circuit interrupter shall be installed in the branch circuit supplying fixtures operating at more than 15 voltsSECT.680.23(A)(3)
Receptacles located within 20 feet of the inside walls of a swimming pool require GFCI protection.
6. a)
True
b)
False ## CORRECT --> All 125-volt receptacles located w ithin 20 ft (6.08 m) of the inside w alls of a pool or fountain shall be protected by a ground-fault circuit interrupter.SECT.680.22(A)(4)
7.
A storable swimming pool must not have any dimension over 12 feet. a)
True
b)
False ## CORRECT --> Storable Sw imming or Wading Pool. Those that are constructed on or above the ground and are capable of holding w ater to a maximum depth of 42 in. (1.07 m), or a pool w ith nonmetallic, molded polymeric w alls or inflatable fabric w alls regardless of dimen.SECT.680.2
In a data-processing room the control for the disconnecting means shall be grouped and identified and shall be readily accessible at the principal exit doors.
8. a)
True
b)
False ## CORRECT --> The control for these disconnecting means shall be grouped and identified and shall be readily accessible at the principal exit doors.
A disconnecting means must be provided for all data-processing equipment in a information technology equipment room.
9. a)
True
b)
False ## CORRECT --> The HVAC equipment must also be disconnected.SECT 645.10
10.
Type NM cables are permitted to connect data-processing equipment by under floor wiring.
a)
True
b)
False ## CORRECT --> There is a long list of w iring methods, but NM is not in the list.SECT 645.5(D)(2)
11.
The bottom of a sign must be at least 12 feet above an area accessible to vehicles.
a)
True
b)
False ## CORRECT --> Sign or outline lighting system equipment shall be at least 14 ft (4.4 m) above areas accessible to vehicles unless protected from physical damage.SECTION 600.9 (A)
12.
Electric signs using incandescent lamps must be marked with the number of lampholders.
a)
True
b)
False ## CORRECT --> Signs and outline lighting systems w ith incandescent lamp holders shall be marked to indicate the maximum allow able w attage of lamps.
13. a)
A lighting fixture is permitted in a clothes closet if an 18-inch clearance is maintained from the storage area. True
b)
False ## CORRECT --> SECT 410.16 (C)
14.
An AC general use snap switch must not be used to control a tungstenfilament lamp loads.
a)
True
b)
False ## CORRECT --> SECTION 404.14(A)
15.
Junction boxes must be accessible.
a)
True
b)
False ## CORRECT --> Conduit bodies, junction, pull, and outlet boxes shall be installed so that the w iring contained in them can be rendered accessible w ithout removing any part of the buildingSECTION 314.29
16.
A duplex receptacle in a box reduces the number of allowed conductors by two.
a)
True
b)
False ## CORRECT --> SECTION 314.16 (B)(4)
17.
Edison-base fuses are acceptable for new installations.
a)
True
b)
False
## CORRECT --> Plug fuses of the Edison-base type shall be used only for replacements in existing installations w here there is no evidence of overfusing or tampering.
18.
Flexible metallic tubing may not be used in lengths over 5 feet.
a)
True
b)
False ## CORRECT --> 6 ft. SECTION360.12(6)
19.
EMT installed in the ground in cinder concrete must have a protective layer of noncinder concrete at least 2 inches thick.
a)
True
b)
False ## CORRECT --> In cinder concrete or cinder fill w here subject to permanent moisture unless protected on all sides by a layer of noncinder concrete at least 2 in. (50.8 mm) thick or unless the tubing is at least 18 in. (457 mm) under the fill.
20.
The largest size NM cable has No. 2 copper conductors or No. 2 aluminum conductors.
a)
True
b)
False ## CORRECT --> The pow er conductors shall be sizes No. 14 through No. 2 w ith copper conductors or sizes No. 12 through No. 2 w ith aluminum or copper-clad aluminum conductors.
2008 NEC Review Practice Test 7 Course Name: 2008 NEC Review Quiz Number: No. 7 Teacher: Gerald Newton Teacher's Home Page: http://www.electrician2.com
Teacher's Email:
[email protected]
No. of Questions= 20
1.
Type MV cable is rated 2,001-volts or higher. a)
True
b)
False ## CORRECT --> Type MV cable is a single or multiconductor solid dielectric insulated cable rated 2001 volts or higher.section 328.2
Open wiring on insulators above 6 feet from the floor does not require protection.
2. a)
True
b)
False ## CORRECT --> Conductors w ithin 7 ft (2.13 m) from the floor shall be considered exposed to physical damage. sect.398.15(c)
3.
Cable tray systems must not be used in hoist ways. a)
True
b)
False ## CORRECT --> sect 392.4
Flexible metal conduit may be used to protect conductors emerging from the ground and run on a pole.
4. a)
True
b)
False
## CORRECT --> Direct-buried conductors and cables emerging from the ground shall be protected by enclosures or racew ays extending from the minimum cover distance required by Section 300.5(D)(1) below grade to a point at least 8 ft (2.44 m) above finished grade.sect.348.12(6)
Under normal conditions, direct buried cables must be buried at least 24 inches.
5. a)
True
b)
False ## CORRECT --> In general the requirement is 24 inches w ith many other depths given.sectiin 300.5(A)&TABLE 300.5
A No. 6 copper conductor in a vertical raceway must be supported at least every 80 feet.
6. a)
True
b)
False ## CORRECT --> SECTION 300.19(A) & TABLE 300.19(A)
7.
Conductors of size No. 1 for general use may not be run in parallel. a)
True
b)
False ## CORRECT --> Aluminum, copper-clad aluminum, or copper conductors of size No. 1/0 and larger, comprising each phase, neutral, or grounded circuit conductor, shall be permitted to be connected in parallel (electrically joined at both ends to form a single conductor).SECTION 310.4
A connection of a No. 8 conductor to a terminal can be by means of a pressure connector or solder lug.
8. a)
True
b)
False
## CORRECT --> Connection of conductors to terminal parts shall ensure a thoroughly good connection w ithout damaging the conductors and shall be made by means of pressure connectors (including set-screw type), solder lugs, or splices to flexible leads. Connection by means of w ire-binding screw s or studs and nuts that
At least 4 Inches of free conductor must be left at each outlet to connect luminaires.
9. a)
True
b)
False ## CORRECT --> 6 inches, not 4 inches.SECTION 300.14
10.
Holes in studs for cables must be in the center and not less than 1 inch from the nearest edge of the stud.
a)
True
b)
False ## CORRECT --> By Section 300.4(A)(1) the edge of holes must be 1 1/4 inches from nearest edge.SECTION 300.4(A)(1)
11.
The smallest fixture wire permitted by the Code is size No. 18.
a)
True
b)
False ## CORRECT --> SECTION 402.3 AND TABLE 402.3
12.
Flexible cords may not be used if they are concealed behind building walls, ceilings or floors.
a)
True
b)
False
## CORRECT --> SECTION 400.8
13.
When six current-carrying conductors are installed in a raceway, the maximum load current of each must be reduced to 70 per cent.
a)
True
b)
False ## CORRECT --> 80 percent, not 70 percent. See the Table.TABLE 310.15(B)(2)(a)
14.
A No. 14 grounded conductor in a circuit must have a white or gray color.
a)
True
b)
False ## CORRECT --> There are other rules, too.SECTION 200.6(A)
15.
A feeder tap less then 25 feet long requires overcurrent protection if the ampacity of the tap conductors is at least one-third of the ampacity of the feeder conductors.
a)
True
b)
False ## CORRECT --> SECTION 240.21(B)(2)
16.
A conductor in a general circuit with an ampacity of 735-amperes may be protected by an 800-ampere fuse.
a)
True
b)
False
## CORRECT --> SECTION 240.4(B)
17.
A three-phase air conditioner must be directly connected to a recognized wiring method and not by flexible cord.
a)
True
b)
False ## CORRECT --> A room air conditioner that is rated three phase or rated over 250 volts shall be directly connected to a w iring method recognized in Chapter 3, and provisions of Art 440 Part G shall not apply.SECTION 440.60
18.
An attachment plug and receptacle may disconnect cord-connected household refrigerating equipment.
a)
True
b)
False ## CORRECT --> SECTION 422.16
19.
Type AC cable must not be used to connect motors to their supply.
a)
True
b)
False ## CORRECT --> SECTION 320.10 &320.12
20.
The frames of stationary motors supplied by metal-enclosed wiring must be grounded.
a)
True
b)
False
## CORRECT --> SECTION 430.242
2008 NEC Review Practice Test 8 Course Name: 2008 NEC Review Quiz Number: No. 8 Teacher: Gerald Newton Teacher's Home Page: http://www.electrician2.com Teacher's Email:
[email protected]
No. of Questions= 20
A disconnecting means for a 2,300-volt motor must be capable of being locked in the open position.
1. a)
True
b)
False ## CORRECT --> SECTION 430.227
The branch circuit overcurrent device may serve as the disconnecting means for stationary motors rated less than one horsepower.
2. a)
True
b)
False ## CORRECT --> For stationary motors of 1/8 hp or less, the branch-circuit overcurrent device shall be permitted to serve as the disconnecting means.SECTION 430.109(B)
3.
A motor controller shall open all conductors to the motor. a)
True
b)
False ## CORRECT --> The controller shall not be required to open all conductors to the motor.SECTION 430.84
In general, enclosures for motor controllers shall not be used as junction boxes unless designs are employed that provide adequate space for this purpose.
4. a)
True
b)
False ## CORRECT --> Enclosures for motor controllers and disconnecting means shall not be used as junction boxes, auxiliary gutters, or racew ays for conductors feeding through or tapping off to the other apparatus unless designs are employed that provide adequate space.SECTION 430.10(A)
Heating panels for de-icing must not exceed a rating of 120-watts/square foot.
5. a)
True
b)
False ## CORRECT --> There are also heating panel requirements for space heating in Article 424.SECTION 426.20(A)
6.
Excess leads of heating cables must not be cut. a)
True
b)
False ## CORRECT --> Excess leads of heating cables shall not be cut but shall be secured to the underside of the ceiling and embedded in plaster or other approved material, leaving only a length sufficient to reach the junction box w ith not less than 6 in. (152 mm) of free SECTION 424.43(C)
In most cases, heating cables installed on ceiling boards must be secured at intervals not exceeding 16 inches.
7. a)
True
b)
False ## CORRECT --> Cables shall be secured by means of approved stapling, tape, plaster, nonmetallic spreaders, or other approved means at either intervals not exceeding 16 in. (406 mm) or at intervals not exceeding 6 ft (1.83 m) for cables identified for such use.SECTION 424.41(F)
Conductors located above a heated ceiling are considered to operate in a 40 degrees C ambient.
8. a)
True
b)
False ## CORRECT --> SECTION 424.36
9.
The non heating leads of 120-volt space heating cables are yellow, a)
True
b)
False ## CORRECT --> SECTION 424.35
10.
Unit switches may disconnect a heater if other means of disconnection are provided.
a)
True
b)
False ## CORRECT --> A unit sw itch(es) w ith a marked “off” position that is part of a fixed heater and disconnects all ungrounded conductors shall be permitted as the disconnecting means required by this article w here other means for disconnection are provided.SECT.424.19(C)
11.
A cord and plug may be the disconnecting means for a wall-mounted electric oven.
a)
True
b)
False
## CORRECT --> SECT 422.16(B)(3) & 422.33(A)
12.
Dishwashers shall be connected with Type SP-1 flexible cords.
a)
True
b)
False ## CORRECT --> Built-in dishw ashers and trash compactors shall be permitted to be cord- and plugconnected w ith a flexible cord identified as suitable for the purpose in the installation instructions of the appliance manufacturer.SECT.422.16(B)(2) & TABLE 400.4
13.
Flexible cords are permitted only to supply portable appliances.
a)
True
b)
False ## CORRECT --> SECTION 400.7 (A)
14.
Toasters may have live parts exposed to contact.
a)
True
b)
False ## CORRECT --> Appliances shall have no live parts normally exposed to contact other than those parts functioning as open-resistance heating elements, such as the heating element of a toaster, w hich are necessarily exposed.SECT. 422.4
15.
The conductor between the surge arrester and the line and the surge arrester and the grounding connection shall not be smaller than 6 AWG copper or aluminum.
a)
True
b)
False
## CORRECT --> Line and ground connecting conductors shall not be smaller than 6 AWG copper or aluminum.SECT.280.23
16.
If a generator operates at 30-volts, protection of live parts is required when the generator is accessible to unqualified persons.
a)
True
b)
False ## CORRECT --> SECTION 445.14
17.
The nominal voltage of a lead-acid battery is 2.0 volts per cell.
a)
True
b)
False ## CORRECT --> SECTION 480.2
18.
A capacitor operating at 300-volts must be discharged to 50-volts or less within one minute after it is disconnected from the supply.
a)
True
b)
False ## CORRECT --> SECTION 460.6(A)
19.
Capacitor circuit conductors must have an ampacity at least 125% of the rated current of the capacitor.
a)
True
b)
False
## CORRECT --> 135% is the requirement.SECTION 460.8(A)
20.
Potential or voltage transformers installed indoors require primary fuses.
a)
True
b)
False ## CORRECT --> SECTION 450.3(C)
2008 NEC Review Practice Test 9 Course Name: 2008 NEC Review Quiz Number: No. 9 Teacher: Gerald Newton Teacher's Home Page: http://www.electrician2.com Teacher's Email:
[email protected]
No. of Questions= 20
The branch circuit load for a 12-kilowatt electric range in a dwelling is 8kilowatts.
1. a)
True
b)
False ## CORRECT --> SECT 220.55,TABLE 220.55
2.
An appliance always requires a disconnecting means. a)
True
b)
False ## CORRECT --> SECT.422.30
A 40-ampere branch circuit may supply several fixed electric space heaters in a dwelling.
3. a)
True
b)
False ## CORRECT --> SECT.424.3(A)
The rating of the overcurrent protective device for a circuit supplying a hermetic motor-compressor may not exceed 225% of the rated load current under any circumstances.
4. a)
True
b)
False ## CORRECT -->SECT 440.22(A)
To measure the area of a dwelling to determine the lighting load, the outside dimensions, including the garage, are used.
5. a)
True
b)
False ## CORRECT --> SECT.220.12
6.
Under no circumstances can the continuous load supplied by a branch circuit exceed 80% of the conductor ampacity before the application of any derating factors..
a)
True
b)
False ## CORRECT --> SECT.210.19(A)(1) EXCEPTION
7.
A 20-ampere laundry circuit is always required in each dwelling unit. a)
True
b)
False ## CORRECT --> SECTION 210.52(F) EXCEPTION #1 &# 2
Branch circuit conductors supplying fixed resistive type space heaters must be rated at 125% of the heater load.
8. a)
True
b)
False ## CORRECT --> SECT.424.3(B)% 210.19(A)(1)
The computed load of a feeder shall not be less than the sum of the loads on the branch circuits after any applicable demand factors have been applied.
9. a)
True
b)
False ## CORRECT --> SECT.220.40
10. a)
When the standard calculation method is used, the minimum feeder load for a household electric clothes dryer is 5,000 watts. True
b)
False ## CORRECT --> SECT.220.54
11.
The optional calculation method for a dwelling unit may be used when the service is a two-wire, 120-volt service.
a)
True
b)
False ## CORRECT --> SECT.220.82(A)
12.
The optional calculation method for multi-family dwellings does not apply to dwellings whose units have neither electric space heating nor airconditioning.
a)
True
b)
False ## CORRECT --> SECT.220.84(A)
13.
The service-entrance equipment for a one-family dwelling, if rated 200amperes and installed indoors, must be illuminated.
a)
True
b)
False ## CORRECT --> SECT.110.26(D)
14.
The working clearance in front of live parts, operating at 120-volts, must be at least three feet.
a)
True
b)
False ## CORRECT --> SECT.110.26(A)
15.
The minimum headroom around a motor control center must be 6 feet.
a)
True
b)
False ## CORRECT --> SECT.110.26(E)
16.
On a switchboard with bus bars, normally, phase B would have the highest voltage to ground in a high-leg delta arrangement.
a)
True
b)
False ## CORRECT --> SECT.408.3(E)
17.
All panelboards shall have a rating not less than the minimum feeder capacity required for the calculated load.
a)
True
b)
False ## CORRECT --> SECT.408.30
18.
In general, a panelboard shall be protected by an overcurrent protective device having a rating not greater than that of the panelboard. This overcurrent protective device shall be located within the panelboard.
a)
True
b)
False ## CORRECT --> SECT.408.36
19.
The grounding terminal bar is not connected to the neutral bar in a panel board not used as service equipment.
a)
True
b)
False ## CORRECT --> GENERAL RULE IN SECT.408.40 DETAILS IN 250.24(A)(5)
20.
Transformers rated over 35,000-volts must be installed in a vault.
a)
True
b)
False ## CORRECT --> SECTION 450.21(C)
2008 NEC Review Practice Test 10 Course Name: 2008 NEC Review Quiz Number: No. 10 Teacher: Gerald Newton Teacher's Home Page: http://www.electrician2.com Teacher's Email:
[email protected]
No. of Questions= 20
1.
The feeder neutral may be smaller than the ungrounded conductors in some cases.
a)
True
b)
False ## CORRECT --> SECTION 220.61(B)
2.
An individual branch circuit may supply only one utilization equipment. a)
True
b)
False ## CORRECT --> ARTIKEL 100 DEFINITION BRANCH CIRCUIT,INDIVIDUAL
3.
A 30-ampere branch circuit may supply fixed lighting units in a dwelling. a)
True
b)
False ## CORRECT --> SECTION 210.23(B)
A rating of any one cord-and-plug-connected utilization equipment shall not exceed 75 percent of the branch-circuit ampere rating.
4. a)
True
b)
False ## CORRECT --> SECTION 210.23(A)(1)
Heavy-duty type lamp holders are required on branch-circuits having a rating in excess of 20-amperes.
5. a)
True
b)
False ## CORRECT --> SECTION 210.21(A)
6.
The branch-circuit rating is determined by the conductor ampacity. a)
True
b)
False ## CORRECT --> The branch circuit rating is determined by the size of the overcurrent protective device.SECTION 210.3
The wall switch controlled lighting outlet required in dwelling unit kitchens may be a receptacle outlet in lieu of a lighting outlet.
7. a)
True
b)
False ## CORRECT --> SECTION 210.70 (A)(1)EXCEPTION No 1
Receptacle outlets in bathrooms of dwelling units require ground-fault circuit interrupter protection.
8. a)
True
b)
False ## CORRECT --> SECTION 210.8(A)(1)
Unless it is bare, an equipment grounding conductor must always be identified by a continuous green color or a continuous green color with one or more yellow stripes.
9. a)
True
b)
False ## CORRECT --> SECTION 250.119(A)
10.
If a multi-wire branch-circuit has a branch-circuit protective device that opens each ungrounded conductor simultaneously then it can supply lineto-line loads..
a)
True
b)
False ## CORRECT --> SECTION 210.4(C) EXCEPTION No.2
11.
The demand factor for three kitchen unit loads in a restaurant is 90%.
a)
True
b)
False ## CORRECT --> SECTION 220.56 & TABLE 220.56
12.
The minimum service load for each mobile home site in a mobile home park is 12,000 volt-amperes.
a)
True
b)
False ## CORRECT --> It is 16,000 Volt-amperes or the calculated load w hich ever is greater.SECTION 550.31(1)
13.
The optional calculation for computing the feeder or service load for a school would not apply to a school with electric space heating or air conditioning.
a)
True
b)
False ## CORRECT --> SECTION 220.86
14.
The rating of receptacles providing shore power for boats at marinas shall not be less than 30 amperes.
a)
True
b)
False ## CORRECT --> SECTION 555.19(A)(4)
15.
The maximum voltage drop for branch circuits and feeders combined should not exceed 3% of the circuit voltage.
a)
True
b)
False ## CORRECT --> SECTION 210.19(A)FPN No.4
16.
The size and the setting for a circuit breaker used as an overcurrent protective device are identical.
a)
True
b)
False ## CORRECT --> SECTION 240.6(C)
17.
Branch circuits in industrial establishments protected by 15-ampere overcurrent devices may supply load operating at 300 volts or less.
a)
True
b)
False ## CORRECT --> SECTION 210.6(D) & 210.23(A)
18.
A multi-wire branch circuit protected by fuses may supply only one load, or only line-to-neutral loads.
a)
True
b)
False ## CORRECT --> SECTION 210.4(C)
19.
A panelboard shall be protected by an overcurrent protective device having a rating not greater than that of the panelboard. This overcurrent protective device shall be located within or at any point on the supply side of the panelboard.
a)
True
b)
False ## CORRECT --> SECTION 408.36
20.
No separate receptacle load is required in guest rooms of hotels and motels.
a)
True
b)
False ## CORRECT --> The same applies to dw elling unit receptacles in livng rooms and bedrooms.SECTION 220.14(J)
2008 NEC Refresher Part 1 Practice Test 1 Course Name: 2008 NEC Review Quiz Number: No. 11 Teacher: Gerald Newton Teacher's Home Page: http://www.electrician2.com Teacher's Email:
[email protected]
No. of Questions= 20
1.
For dwelling unit with a 240/120 single-phase service the frame of a 4,500 watt 240/120 volt clothes dryer shall be grounded by using the grounding conductor. The minimum size copper conductor is:
a) b) c)
No. 10 No. 8 No. 12 ## CORRECT --> 5,000/240 = 20.8; Requires OCPD = 25 or 30 amperes. By Table 250-122 a 25 or 30 ampere. CB requires a No. 10 copper grounding conductor.SECTION 220.54;240.3 AND TABLE 250.122
2.
The minimum size copper equipment grounding conductor for a 200ampere circuit is:
a) b) c)
No. 8 No. 6 No. 3 ## CORRECT --> TABLE0250.122
3.
When not under concrete, rigid metal conduit must be buried under public highways and streets at least:
a) b) c) d)
24 inches 18 inches 6 inches 4 inches ## CORRECT --> Required for under streets, highw ays, roads, alleys, drivew ays, and parking lotsTABLE 300.5COLUMN 2
4.
120-volt, 20-ampere GFCI protected residential branch circuit may be buried at a minimum depth of :
a) b) c)
12 inches 18 inches 24 inches ## CORRECT --> True for residential branch circuits rated 120 Volts or Less w ith GFCI Protection and Maximum Overcurrent Protection of 20 Amperes TABLE 300.5 COLUMN 4
5.
The listed ampacities of 75 Degrees C. conductors in a raceway must be reduced when the ambient air temperature exceeds:
a) b) c) d)
60 degrees C. 75 degrees C. 90 degrees C. 30 degrees C.
## CORRECT --> TABLE 310.16 CORRECTION FACTOR ON BOTTOM OF TABLE
6.
Horizontal nonmetallic wireways shall be supported where run horizontally at intervals not to exceed _________, and at each end or joint, unless listed for other support intervals. In no case shall the distance between supports exceed 3 m (10 ft).
a) b) c)
3 ft. 5 ft. 6 ft. ## CORRECT --> One of the requirements for nonmetallic extensions is the extension is from an existing outlet on a 15- or 20-ampere branch circuit in conformity w ith the requirements of Article 210.
7.
When NOT using a one-shot bender, the minimum radius of a field bend to the centerline of the conduit for 2-inch rigid metal conduit containing XHHW conductors is:
a) b) c)
9 1/2 inches 12 inches 15 inches ## CORRECT --> Correct per Chapter 9 Table 2 last column.SECT 344.24 AND TABLE 2 IN CHAPTER 9
8.
In a straight run, 2-inch rigid metal conduit with threaded couplings may be supported at intervals not exceeding:
a)
10 feet 12 feet
b) c)
16 feet ## CORRECT --> 16 feet provided the conduit is made up w ith threaded couplings, and such supports prevent transmission of stresses to termination w here conduit is deflected betw een supports.SECTION 344.30(B)(2)& TABLE 344.30(B)(2)
9.
The maximum size of electrical metallic tubing is:
a) b) c)
6-inch 4-inch 2-inch ## CORRECT --> Rigid can be 6 inches maximum, but for EMT the maximum size of tubing shall be the 4-in. electrical trade size.SECTION 350.20(B)
10.
For metallic and nonmetallic, auxiliary gutters must not be filled to greater than:
a) b) c) d)
20 % 30 % 40 % 60 % ## CORRECT --> The sum of the cross-sectional areas of all contained conductors at any cross-section of a sheet metal auxiliary gutter shall not exceed 20 percent of the interior cross-sectional area of the sheet metal or nonmetallic auxiliary gutter.Section366.22(A) & 366.22(B)FOR NOMMETALLIC
11.
The multiplier for bending offsets is called the ________ of the angle used for the offset bends.
a) b) c) d)
sine cosine secant cosecant ## CORRECT --> Cosecant = 1 / sine, is equal to (hypotenuse / side opposite) in a right triangle.
12.
The largest conductor allowed in a standard box without other restrictions is:
a) b) c)
No. 4 No. 8 No. 6 ## CORRECT --> Other is defined as cubic inch requirements.section 314.16
13.
An Alternating-Current or Direct-Current General-Use Snap Switch may control what inductive load as a percentage of its ampere rating?
a) b) c)
80 % 50 % 75 % ## CORRECT --> section 404.14(B)(2)
14.
The ampacity of No. 14 fixture wire is:
a) b) c)
8 amperes 15 amperes 17 amperes ## CORRECT --> TABLE 402.5
15.
When there are exposed live parts on both sides of the working space for a system operating at 480 volts the required distance between the equipment is:
a) b) c)
3 feet 3 1/2 feet 4 feet ## CORRECT --> Falls under Condition 3 Table 110-26(A)(1)SECTION 110.26(A)(1)AND TABLE 110.26 (A)(1)LOCATION AT WORK CLEARANCE RULES
16.
Guarding by elevation for a 600-volt circuit requires an elevation of:
a) b) c)
8 feet 6 1/4 feet 8 1/2 feet
## CORRECT --> By elevation of 8 ft (2.44 m) or more above the floor or other w orking surface.SECTION 110.27(A)(4)
17.
Conduit or fittings must not rise into the bottom of a switchboard enclosure more than:
a) b) c)
8 inches 3 inches 10 inches ## CORRECT --> The conduit or racew ays, including their end fittings, shall not rise more than 3 in. (76 mm) above the bottom of the enclosure.SECTION 408.5
18.
Plug-in-type overcurrent protection devices that are backfed and used to terminate field-installed ungrounded supply conductors ________________ .
a) b) c)
are permitted if locked in place shall be secured in place by an additional fastener that requires other than a pull to release the device from the mounting means on the panel. do not require any additional hardware ## CORRECT --> SECTION 408.36(D)
19.
For a center line radius of 20 inches and a 45 degree bend the developed length of the conduit is found by using the following formula:
a) b)
dl = 20 x 90 x 0.0175. dl = 20 x 45 x 0.0175.
dl = 20 x 90 x tangent of 45 degrees
c)
## CORRECT --> The multiplier 0.0175 is equal to (2 * pi) / 360
20.
For a center line radius of 20 inches and a 90 degree bend the gain is:
8.5 inches
a)
6 inches
b)
4.125 inches
c)
## CORRECT -->( 2*RADIOS)-(DEVELOPED LENGTH)=GAIN
2008 NEC Refresher Part 1 Practice Test 2 Course Name: 2008 NEC Review Quiz Number: No. 12 Teacher: Gerald Newton Teacher's Home Page: http://www.electrician2.com Teacher's Email:
[email protected]
No. of Questions= 20
1.
The length of a Type S cord connecting a trash compactor must not exceed:
a)
18 inches
b)
4 feet
c)
36 inches
## CORRECT --> The length of the cord shall not be less than 18 in. (457 mm) and not over 36 in. (914 mm).SECTION 422.16(b)(1)(1)
2.
Screw-shell lamp holders must not be used with infrared lamps rated over ________ unless the lampholders are identified as being suitable for use with infrared heating lamps rated over 300 watts. a)
300 watts
b)
600 watts
c)
150 watts ## CORRECT --> Screw -shell lamp holders shall not be used w ith infrared lamps rated over 300 w atts, unless the lamp holders are identified as being suitable for use w ith infrared heating lamps rated over 300 w atts.section 422.28(b)
3.
A molded case circuit breaker may serve as the disconnecting means for motor driven appliances rated: a)
Not over one-half horsepower
b)
Not over one horsepower
c)
Not over one-third horsepower
d)
All of the above if the circuit breaker is listed. ## CORRECT --> 422.31(B)FPN-422.34-430.111
4.
A 20-ampere single non motor operated appliance must not be protected at more than: a)
20 amperes
b)
25 amperes
c)
30 amperes
## CORRECT --> If the overcurrent protection rating is not marked and the appliance is rated over 13.3 amperes, not exceed 150 percent of the appliance rated current. Where 150 percent of the appliance rating does not correspond to a standard overcurrent device ampere SECTION 422.11(E)(3)
5.
The minimum length of non heating leads furnished for heating cables is:
a)
7 feet
b)
8 inches
c)
3 feet ## CORRECT --> Part V. Electric Space-Heating Cables: 424-34. Heating Cable Construction Heating cables shall be furnished complete w ith factory-assembled non heating leads at least 7 ft (2.13 m) in length.ARTIKEL 424 PART V,SECTION 424.34
6.
The non-heating leads of 240-volt heating cable are:
a)
yellow
b)
blue
c)
red ## CORRECT --> SECTION 424.35
7.
Wiring above heated ceilings must be spaced above the ceiling at least:
a)
4 inches
b)
2 inches
c)
3 inches ## CORRECT --> Wiring located above heated ceilings shall be spaced not less than 2 in. (50.8 mm) above the heated ceiling and shall be considered as operating at an ambient of 50ºC (122ºF). SECTION 424.94
8.
The separation between heating cables and outlet box must be at least:
a)
8 inches
b)
2 inches
c)
6 inches ## CORRECT --> Heating elements of cables shall be separated at least 8 in. (203 mm) from the edge of outlet boxes and junction boxes that are to be used for mounting surface lighting fixtures. A clearance of not less than 2 in. (50.8 mm) shall be provided from recessed luminaires and their trims, ventilating openings,
9.
Adjacent runs of heating cables not exceeding 2 3/4 watts/foot in ceilings must be spaced on centers of: a)
1 1/2 inches
b)
16 inches
c)
1 inch ## CORRECT --> Adjacent runs of cable not exceeding 2¾ w atts/ft (2¾ w atts/305 mm) shall not be installed less than 1½ in. (38 mm) on centers.SECTION 424.41(b)
10.
The branch-circuit conductors supplying a resistance heater without a motor rated at 16 amperes must have an ampacity of: a)
16 amperes
b)
20 amperes
c)
32 amperes ## CORRECT --> The ampacity of the branch-circuit conductors and the rating or setting of overcurrent protective devices supplying fixed electric spaceheating equipment consisting of resistance elements w ith or w ithout a motor shall not be less than 125% of total loadSECTION 424.3(B)
11.
When a dispute or a problem arises concerning the interpretation of the National Electrical Code, which of the following would be the most likely to solve the problem? a)
The electrical contractor
b)
The I.A.E.I. organization
c)
An electrical engineer
d)
The chief electrical inspector ## CORRECT --> SECTION 90.4
12.
The length of a pull box used in straight pulls for No. 4 and larger conductors for 600 volts and under shall not be less than how many times the trade diameter of the largest raceway? a)
five
b)
six
c)
eight
d)
ten ## CORRECT --> In straight pulls, the length of the box shall not be less than eight times the trade diameter of the largest racew ay.SECTION 314.28(A)(1)
13.
Metal plugs or plates used with nonmetallic boxes, conduit bodies or fittings shall be recessed at least, how far from the outer surface? a)
1/4 inch
b)
Flush
c)
1/2 inch
d)
5/8 inch ## CORRECT --> Metal plugs or plates used w ith nonmetallic boxes or conduit bodies shall be recessed at least ¼ in. (6.35 mm) from the outer surface of the box.SECTION 110.12(A)
14.
Which of the following locations is not permitted for the use of surface raceways (wiremold)? a)
A dry location
b)
Concealed Under plaster
c)
Under data processing room floors.
d)
In Class I division 2 locations ## CORRECT --> SECTION 366.12(5)FOR METALLIC AND 388.12(1) FOR NON METALLIC
15.
Generally, under floor raceways not more than 4 inches wide shall nave no less than how much concrete or wood above them? a)
2 inches
b)
4 inches
c)
3/4 inch
d)
1/2 inch ## CORRECT --> Half-round and flat-top racew ays not over 4 in. (102 mm) in w idth shall have not less than ¾ in. (19 mm) of concrete or w ood above the racew ay.SECTION 390.3(A)
16.
In a Class 1, Division 1 location a conduit passing through into a non hazardous location will have the sealing fitting installed where? a)
On both sides of the boundary
b)
On either side of the boundary
c)
No seal required under the circumstances
d)
At the first fitting ## CORRECT --> In each conduit run leaving a Class I, Division 1 location. The sealing fitting shall be permitted on either side of the boundary of such location w ithin 10 ft (3.05 m) of the boundary.SECTION 501.15(A)(4)
17.
Boxes which are installed in walls of non combustible material will be installed so that the front edge of the box is no further back than? a)
Flush
b)
1/2 inch
c)
3/8 inch
d)
1/4 inch ## CORRECT --> In w alls or ceilings of concrete, tile, or other noncombustible material, boxes shall be installed so that the front edge of the box w ill not be set back of the finished surface more than ¼ in. (6.35 mm)SECTION 314.20.
18.
Live parts exposed on the front of a switchboard are present. The working space in front of the switchboard will not be less than? a)
24 inches
b)
30 inches
c)
36 inches
d)
42 inches ## CORRECT --> SECTION 110.26(A)(1)& TABLE 110.26(A)(1)
19.
What is the minimum size of conductor which requires an insulation bushing when entering into a raceway in a junction box? a)
No. 6 THW
b)
No. 4
c)
No. 10 TW
d)
No. 12 ## CORRECT --> Where racew ays containing ungrounded conductors No. 4 or larger enter a cabinet, box enclosure, or racew ay, the conductors shall be protected by a substantial fitting providing a smoothly rounded insulating surface, unless .....SECTION 300.4(G)
20.
For a conductor at a terminal which leaves a cabinet the minimum wire bending space at the terminal shall be how much if the conductor is a 250 MCM conductor and leaves through wall opposite its removable terminal? a)
4 inches
b)
4 1/2 inches
c)
5 inches
d)
6 1/2 inches ## CORRECT --> Reduce the 8 1/2 inch requirement in Table 312.6(B) note 2 by tw o inches since there is a lay in terminal.SECTION 312.6(B)(2) AND TABLE 312.6(B) WITH NOTE 2
The rules are found in Section 210-52. Note: These are the minimum number of receptacles. Receptacle outlets required by Section 210-52 for a living room shall be in addition to any receptacle that is part of a lighting fixture or appliance, located within cabinets or cupboards, or located more than 5½ ft (1.68 m) above the floor. In every living room receptacle outlets shall be installed in accordance with the general provisions specified in (1) through (3). (1) Spacing. Receptacles shall be installed so that no point along the floor line in any wall space is more than 6 ft (1.83 m), measured horizontally, from an outlet in that space. Receptacle outlets shall, insofar as practicable, be spaced equal distances apart. (2) Wall Space. As used in this section, a wall space shall include the following: a. Any space 2 ft (610 mm) or more in width (including space measured around corners) and unbroken along the floor line by doorways, fireplaces, and similar openings b. The space occupied by fixed panels in exterior walls, excluding sliding panels
2008 NEC Refresher Part 1 Practice Test 3 QCourse Name: 2008 NEC Review
Quiz Number: No. 13 Teacher: Gerald Newton Teacher's Home Page: http://www.electrician2.com Teacher's Email:
[email protected]
No. of Questions= 20
1.
What is the minimum number of receptacle outlets required in the following diagram. Web Reference
a) b) c) d)
5 6 7 8 ## CORRECT --> 210.52
2.
What does the following drawing represent?
a)
Current transformer
b) c) d)
Auto transformer Single-Phase transformer Three phase transformer ## CORRECT -->
3.
A 50 volt generator which is driven by a single motor is protected by the overcurrent device protecting the motor only when the generator is delivering no more than what percent of its full-load rated current?
a) b) c) d)
100 percent 125 percent 150 percent 80 percent
## CORRECT --> Generators operating at 65 volts or less and driven by individual motors shall be considered as protected by the OCPD protecting the motor if these devices w ill operate w hen the generators are delivering not more than 150 percent of their FLA.SECT.445.4(C)
4.
The overcurrent protection for conductors shall not exceed how many amperes when the control circuit conductor for the motor is No. 12 AWG copper and do not extend beyond the motor control enclosure?
a) b) c) d)
100 amperes 120 amperes 60 amperes 20 amperes ## CORRECT --> 120 amperes in Column B of Table 430-72(b)TABLE 430.72(B)COLUMN B
5.
Generally, what is the minimum number of overload units in a three phase motor?
a) b) c) d)
One Two Three None ## CORRECT --> 3, one in each phaseTABLE 430.37
6.
If the overcurrent protection rating is not marked and the appliance is rated 13.3 amperes or less the branch-circuit rating of a single non-motor operated appliance shall have a minimum rating of what?
a) b) c) d)
150 percent of the full load rating of the appliance 100 percent of the full load rating of the appliance 20 amperes 30 amperes ## CORRECT --> If the overcurrent protection rating is not marked and the appliance is rated 13.3 amperes or less, not exceed 20 amperes.SECT.422.11(E)(2)
7.
A cutout box installed in a wet location shall be what?
a) b) c) d)
Rain tight Weatherproof Waterproof Rainproof ## CORRECT --> Enclosures installed in w et locations shall be w eatherproof.SECT.312.2
8.
A junction box used in a system rated 1,000 volts shall have a marking on it of what?
a) b) c) d)
DANGER HIGH VOLTAGE KEEP OUT DANGER - HIGH VOLTAGE - KEEP OUT
## CORRECT --> Covers for boxes shall be permanently marked *DANGER - HIGH VOLTAGE - KEEP OUT*SECT.314.72(E)
9.
A nonmetallic wireway and metal wire way cannot be filled to more than 20 percent of their cross sectional area. What is the maximum number of current carrying conductors allowed in a metal wire way when no derating is required?
a) b) c) d)
80 50 30 20 ## CORRECT --> Metal w irew ays shall not contain more than 30 current-carrying conductors at any cross section. SECT.376.22.(B)
10.
Metal surface raceways having splices and taps shall be permitted as long as the splices and taps, and conductors do not fill the raceway more than how much of the area of the raceway at that point?
a) b) c) d)
40 percent 75 percent 50 percent 60 percent ## CORRECT --> Splices and taps shall be permitted in surface metal racew ays having a removable cover that is accessible after installation. The conductors, including splices and taps, shall not fill the racew ay to more than 75 percent of its area at that point.SECT.386.56
11.
Panelboards installed out-of-doors shall be marked in which manner?
a) b) c) d)
Weatherproof Rain tight Water tight Outdoor usage ## CORRECT --> Enclosures installed in w et locations shall be w eatherproof.SECTION 408.37 &312.2
12.
An effective grounded path requires which of the following?
a) b) c) d)
A solid metallic object The ability to conduct fault-current An energized source Sufficient low impedance to limit the voltage to ground ## CORRECT --> The fault current path shall be permanent and electrically continuous, shall be capable of safely carrying the likely maximum fault current.SECTION 250.2 DEFINITIONS
13.
Exposed non–current-carrying metal parts of fixed equipment likely to become energized shall be connected to the equipment grounding conductor under the following condition:
a)
Where within 8 feet horizontal and 5 feet vertical of grounded metal objects and subject to contact by persons.
b)
Where within 5 feet vertical and 5 feet horizontal of grounded metal objects and subject to contact by persons.
c)
Where within 8 feet vertical and 5 feet horizontal of grounded metal objects and subject to contact by persons.
d)
Where within 8 feet vertical and 8 feet horizontal of grounded metal objects and subject to contact by persons. ## CORRECT --> SECTION 250.110
14.
Circuit breakers which are used to switch 120 volt fluorescent lights on an off shall be marked with what listing?
a) b) c) d)
U.L. approved 5,000 RMS SWD or HID 10,000 RMS ## CORRECT --> Circuit breakers used as sw itches in 120-volt and 277-volt fluorescent lighting circuits shall be listed and shall be marked *SWD.*SECT.240.83(D)
15.
According to the NEC, service-entrance conductors for over 600 volts are protected by a circuit breaker if it has how many times the ampacity of the conductor for its trip setting? (Short circuit protection)
a) b) c) d)
3 times 5 times 6 times 8 times ## CORRECT --> A fuse rated in continuous amperes not to exceed three times the ampacity of the conductor, or a circuit breaker w ith a trip setting of not more than six times the ampacity of the conductors, shall be considered as providing the required sc protection. SECT.230.208
16.
What is the smallest size of service-entrance copper conductors permitted when installed in a non-metallic raceway when supplying three single branch circuit loads in a commercial building.?
a) b) c) d)
No. 10 No. 8 No. 6 No. 4 ## CORRECT -->SECTION 230.42(B),230.79(D),110.14,230.42(A), 230.90(A) EXCEPTION #2,240.6 & 240.3(B)
17.
When shall the service ground-fault protection system be tested?
a) b) c) d)
When it is installed When it is manufactured When it is inspected When it is energized for the first time ## CORRECT --> The ground-fault protection system shall be performance tested w hen first installed on site. The test shall be conducted in accordance w ith instructions that shall be provided w ith the equipment. A w ritten record of this test shall be made and shall be a. SECTION 230.95(C)
18.
What is the maximum time of delay permitted for a feeder disconnect rated 1000 amperes or more on a solidly grounded wye electrical system of more than 150 volts to ground, but not exceeding 600 volts phase-to-phase, that is NOT (1) a continuous industrial process where a orderly shutdown will introduce additional or increased hazards, and (2) is also not for a fire pump, and (3) does not have a ground fault protected service ? 1/2 second
a) b) c) d)
1second 3 seconds 100 milliseconds ## CORRECT --> The maximum setting of the groundfault protection shall be 1200 amperes, and the maximum time delay shall be one second for ground-fault currents equal to or greater than 3000 amperes. SECTION 215.10 THAT REFERS TO 230.95 (A)
19.
What is the minimum size rating of a 240/120 volt single phase service entrance conductors supplying a single family dwelling having 1200 square feet of living space and a net computed load of 4800 KA?
a) b) c) d)
100 amperes 200 amperes 60 amperes 30 amperes ## CORRECT --> For a one-family dw elling, the service disconnecting means shall have a rating of not less than 100 amperes, 3-w ire.SECTION 230.42(B) AND 230.79(C)
20.
Given a single family residence with a general lighting load of 22,500 watts. What is the demand lighting load for the residence?
a) b) c) d)
22,500 watts 19,500 watts 6,825 watts 9,825 watts
## CORRECT --> First 3,000 va at 100 percent, the remainder at 35 percent. 3,000 + .35 (22,500 - 3,000) = 9,825 va. TABLE 220.12 for 3va/sq.ft and table 220.42 for the demand factor
2008 NEC Refresher Part 1 Practice Test 4 Course Name: 2008 NEC Review Quiz Number: No. 14 Teacher: Gerald Newton Teacher's Home Page: http://www.electrician2.com Teacher's Email:
[email protected]
No. of Questions= 20
1.
For Interlocked-Type Armor or Corrugated Sheath Type Metal Clad Cable bends shall be made so that the cable will not be damaged, and the radius of the curve of the inner edge of any bend shall not be less than: a)
Seven times the external diameter of the metallic sheath.
b)
Ten times the external diameter of the metallic sheath.
c)
Twelve times the external diameter of the metallic sheath.
d)
Fifteen times the external diameter of the metallic sheath. ## CORRECT --> section 330.24(B)
2.
How many amperes does a 83,100 kilowatt load with a .8 power factor draw in a 480 volt, three phase circuit? a)
100 amperes
b)
125 amperes
c)
1250 amperes
d)
1,000 amperes
## CORRECT --> Pow er (w atts) = SQRT3 x Volts x Amperes x Pow er Factor, Amperes = Pow er / (SQRT 3 x Volts x Pow er Factor); Amperes = 83,100 / (1.732 x 480 x .8); Amperes = 125 amperes
3.
Using the DC resistance method and values from Table 8 in Chapter 9 of the NEC what is the Voltage drop for a No. 12 copper solid conductor used on a two wire 120 volt circuit that is 200 feet long one-way and draws 12 amperes? Select nearest answer. a)
12.3 volts
b)
6 volts
c)
9.3 volts
d)
Not enough information to find the answer. ## CORRECT --> From Table 8 The DC resistance is (400/1000) x .193 = 0.772; The voltage drop is 12 amperes x 0.772 = 9.3volts
4.
What is the maximum rating for fastened in place cord- and plug-connected utility equipment that can be installed on a 20 ampere circuit if the circuit also supplies lighting outlets? a)
20 amperes
b)
16 amperes
c)
12 amperes
d)
10 amperes ## CORRECT --> The total rating of utilization equipment fastened in place, other than lighting fixtures, shall not exceed 50 percent of the branch-circuit ampere rating w here lighting units are also supplied.section 210.24(A) (2)
5.
What is the maximum cord and plug connected load to a receptacle rated 15 amperes and installed on a 20 ampere circuit? a)
20 amperes
b)
16 amperes
c)
12 amperes
d)
10 amperes ## CORRECT --> section 210.21(B)(2) and table 210.21(B)(2)
6.
What is the maximum size circuit rating permitted when using a duplex receptacle which is rated at 20 amperes? a)
20 amperes
b)
15 amperes
c)
16 amperes
d)
10 amperes ## CORRECT --> table 210.24
7.
What is the minimum load allowed for each 2-wire laundry branch circuit installed in a dwelling? a)
2,400 volt-amperes
b)
2,000 volt-amperes
c)
1,800 volt-amperes
d)
1,500 volt-amperes ## CORRECT --> A load of not less than 1500 voltamperes shall be included for each 2-w ire laundry branch circuit installed as required by Section 210-11(c) (2).section 220.54(B)
8.
Drawings designed to show the exact location of the installed circuit are commonly referred to as a? a)
Blue print
b)
Schematic diagram
c)
As-build drawing
d)
One-line drawing
e)
red-lined blue prints. ## CORRECT -->
9.
What is the horsepower output of a 75 horsepower, three phase motor with a 85% efficiency and a .80 power factor if the voltage is 230 volts and the motor draws 194 amperes? a)
60 Horsepower
b)
70 Horsepower
c)
80 Horsepower
d)
90 Horsepower ## CORRECT --> hp = 1.732 x 194 x 230 x .85 x .8 / 746; hp = 70.4
10.
Given 5 ranges with the following loads: 6 Kw, 4.5 Kw, 8 Kw, 3.5 Kw, and 4 Kw. What is the minimum computed load for these household ranges when all are connected to one feeder? a)
26 Kva
b)
20 Kva
c)
11.7 Kva
d)
16.2 Kva ## CORRECT --> From Column C demand factor is 45%; .45 x (6 + 4.5 + 8+ 3.5 + 4) = 11.7 kvasection 220.55 and table 220.55
11.
Given two 400 ampere 480 volt, 3-phase, 4-wire panels connected by one neutral. What percent of the neutral load must be taken for the first 200 amperes? a)
70 percent
b)
125 percent
c)
80 percent
d)
100 percent ## CORRECT --> The feeder or service neutral load shall be the maximum unbalance of the load determined by this article. section 220.61O(2)
12.
The minimum vertical distance from ground for service-drop conductors rated 240,Volts, and running over a public drive-way shall be? a)
10 feet
b)
18 feet
c)
15 feet
d)
12 feet ## CORRECT --> 18 ft (5.49 m) — over public streets, alleys, roads, parking areas subject to truck traffic, drivew ays on other than residential property, and other land such as cultivated, grazing, forest, and orchard SECTION 230.24(B)(4)
13.
It is permissible to install 10 feet service entrance conductors in all of the following except? a)
Electrical metallic tubing
b)
Intermediate metal conduit
c)
Flexible metallic conduit
d)
Rigid metallic conduit ## CORRECT --> Flexible metal conduit not over 6 ft (1.83 m) long or liquidtight flexible metal conduit not over 6 ft (1.83 m) long betw een racew ays, or betw een racew ay and service equipment is allow ed.SECTION 230.43(15)
14.
Where the service disconnecting means does not disconnect the grounded conductor from the premises wiring, you must install which of the following: a)
A disconnecting link,or terminal
b)
A bonding bushing
c)
A grounding bushing
d)
An additional ground rod ## CORRECT --> Where the service disconnecting means does not disconnect the grounded conductor from the premises w iring, other means shall be provided for this purpose in the service equipment.SECTION 230.75
15.
Which insulation can be used for conductors in (1) raceways used out of doors, (2) in raceways in concrete slabs indoors, and (3) in raceways that are directly buried in earth. a)
THHN
b)
RHH
c)
XHHW
d)
RH ## CORRECT --> Insulated conductors and cables used in w et locations shall be MTW, RHW, RHW-2, TW, THW, THW-2, THHW, THHW-2, THWN, THWN-2, XHHW, XHHW-2, ZW ARTIKEL 100 AND SECTION 310.8(c)
16.
What is the synchronous speed in RPM of a motor with eight poles when connected to a 400 hertz supply? a)
12,000 RPM
b)
6,000 RPM
c)
3,000 RPM
d)
1200 RPM ## CORRECT --> Sync RPM = (hertz x 120 )/ Number of Poles; Sync RPM = (400 x 120 )/ 8 = 6,000
17.
A megger is used to measure: (select best answer)
a)
insulation breakdown resistance
b)
resistance
c)
resistance of ground rods
d)
all of the above ## CORRECT --> How ever, meggers are usually used to measure insulation breakdow n resistance.
18.
Given four parallel 500 kcmil XHHW/CU with a 4 each 400 kcmil neutral conductors per phase run in 4 each metal conduits. What should the configuration be per each conduit. a)
A-phase, B-phase, C-phase, Neutral in each conduit.
b)
AAAA in one conduit, BBBB in one conduit, CCCC in one conduit NNN in one conduit.
c)
Doesn't matter.
d)
None of the above ## CORRECT --> The requirement to run all circuit conductors w ithin the same racew ay, auxiliary gutter, cable tray, trench, cable, or cord shall apply separately to each portion of the paralleled installation.SECTION 300.3(B)(1)
19.
In general the minimum size conductors that can be used for up to 2,000 volts for power and lighting are: a)
No. 18 copper, No. 14 aluminum
b)
No. 14 copper, No. 12 aluminum
c)
No. 18 copper, No. 16 aluminum ## CORRECT --> The minimum size of conductors shall be as show n in Table 310.5.TABLE 310.5 SECTION 310.5
20.
Given three (3) 300 kcmil THWN Cu conductors in (3) sets being utilized as service-entrance conductors. What is the minimum size for the copper grounding electrode conductor? a)
No. 2
b)
4/0
c)
1/0
d)
2/0 ## CORRECT --> 3 x 300 = 900 kcmil; per Table 250-66 900 kcmil requires a 2/0 copper grounding electrode conductor.SECTION 250.66 AND TABLE 250.66
2008 NEC Refresher Part 1 Practice Test 5 Course Name: 2008 NEC Review Quiz Number: No. 15 Teacher: Gerald Newton Teacher's Home Page: http://www.electrician2.com Teacher's Email:
[email protected]
No. of Questions= 20
1.
What is the maximum temperature rating permitted for TW wire?
a) b) c) d)
140 degrees C 60 degrees C 75 degrees C 167 degrees C ## CORRECT --> 60 Degrees per Table 310-13.
2.
What is the maximum size fuse allowed on a No. 12 THHN CU conductor that is not a tap conductor?
a) b) c) d)
20 amperes 15 amperes 25 amperes 30 amperes ## CORRECT --> The overcurrent protection shall not exceed 15 amperes for No. 14, 20 amperes for No. 12, and 30 amperes for No. 10 copper; or 15 amperes for No. 12 and 25 amperes for No. 10 aluminum and copperclad alum. section240.4(D)(5)
3.
In general, the smallest permissible copper service drop conductor is No. 8
a) b)
True False ## CORRECT --> Minimum Size. The conductors shall not be smaller than No. 8 copper or No. 6 aluminum or copper-clad aluminum.section 230.23(B)
4.
A 200 Ampere overcurrent protective device requires a No. _________ equipment grounding conductor.
a) b) c) d)
2 4 6 8 ## CORRECT -->table 250.122
5.
Flexible Metal conduit not supported for 3 feet and used to provide flexibility at equipment shall be equipped with an equipment grounding conductor.
a) b)
True False ## CORRECT --> Where used to connect equipment w here flexibility is required, an equipment grounding conductor shall be installed.section 348.60
6.
For a high impedance grounded system the neutral cannot be smaller than No. _____ Copper.
a) b) c) d)
8 6 4 2 ## CORRECT --> In no case shall the neutral conductor be smaller than No. 8 copper or No. 6 aluminum or copper-clad aluminum.section 250.36(B)
7.
A 120/240 V feeder shall have a rating of at least _______Amperes to supply a 9 kva noncontinuous load and a 12 kva continuous load.
a) b) c)
87.5 amperes 100 amperes 125 amperes
## CORRECT --> 1.25 x 12,000 va + 9,000 va= 24,000 va; 24,000 va/ 240 volts= 100 amperes.section 215.2(A) (1)
8.
Any available wall space in a dwelling shall be within 7' of a plug receptacle.
a) b)
True False ## CORRECT --> Receptacles shall be installed so that no point along the floor line in any w all space is more than 6 ft (1.83 m), measured horizontally, from an outlet in that space.section 210.52(A)(1)
9.
Switch enclosures and panelboards, under certain conditions, may be used as junction boxes.
a) b)
True False ## CORRECT --> Enclosures for sw itches or overcurrent devices shall not be used as junction boxes, auxiliary gutters, or racew ays for conductors feeding through or tapping off to other sw itches or overcurrent devices, unless adequate space for this purpose is provided.section312.8
10.
Under certain conditions short sections of metal raceway need not be grounded.
a) b)
True False ## CORRECT --> Short sections of metal enclosures or racew ays used to provide support or protection of cable assemblies from physical damage shall not be required to be grounded.section250.86 exception 1,2 & 3
11.
Which is the correct hookup configuration for a solidly grounded Delta
Wye 480 volt to 208/120 volt transformer shown below?
a) b) c)
A B C ## CORRECT -->
12.
Conductors of dissimilar metals shall not be intermixed in a terminal or splicing connector where physical contact occurs, unless the device is _________ for the purpose and conditions of use.
a) b) c)
listed identified labeled
## CORRECT --> Conductors of dissimilar metals shall not be intermixed in a terminal or splicing connector w here physical contact occurs betw een dissimilar conductors unless the device is identified for the purpose and conditions of use. section 110.14
13.
The service disconnecting means may consist of not more than six switches or circuit breakers.
a) b)
True False ## CORRECT --> There shall be no more than six disconnects per service grouped in any one location section230.71(A)
14.
For dwelling units the service or feeder demand capacity necessary for four 10 kw electric ranges is ______kw.
a) b) c) d)
15 17 19 21 ## CORRECT --> Column C of Table 220.55 show s 17 kw for 4 ranges not over 12 kw each.section 220.55 table220.55 column C
15.
Which diagram shows the correct connection for three start stop stations for a motor controller. The diagrams do not show the holding contacts.
a) b)
A B C
c) ## CORRECT --> The stop stations are connected in series w ith the start stations and the start stations are connected in parallel.
16.
The clearance of 120/240 V service drop conductors over residential driveways not subject to truck traffic shall be no less than ______ ft.
a) b) c) d)
10 feet 12 feet 15 feet 18 feet
## CORRECT --> 12 ft (3.66 m) — over residential property and drivew ays.section 230.24(B)(1)
17.
The first 20,000 VA of computed load in a hotel shall be assessed at ______ percent.
a) b) c)
30 40 50 ## CORRECT --> Table 220-11 section 220.42 and table 220.42
18.
Unless otherwise specified, conductors used to carry current shall be of _______.
a) b) c)
Copper Aluminum Bronze ## CORRECT --> Conductors normally used to carry current shall be of copper unless otherw ise provided in this Code. Where the conductor material is not specified, the material and the sizes given in this Code shall apply to copper conductors. section 110.5
19.
The copper grounding electrode conductor for a 350 kcmil, 120/240 V service installation, if run to a ground rod electrode, shall be no smaller than No. ______
a) b)
6 copper 4 copper
2 copper
c)
## CORRECT --> Where the grounding electrode conductor is connected to made electrodes as permitted in Section 250-52(c) or (d), that portion of the conductor that is the sole connection to the GEC shall not be required to be larger than No. 6 copper.table 250.66 and section 250.66(A)
20.
The smallest permissible LISTED driven ground rod electrode made of nonferrous materials is_______ inches in diameter. 3/4
a) b) c)
5/8 1/2 ## CORRECT --> nonferrous rods, or their equivalent shall be listed and shall not be less than ½ in. (12.7 mm) in diameter. 250.52(A)(5)(b)
2008 NEC Refresher Part 2 Practice Test 1 Course Name: 2008 NEC Review Quiz Number: No. 16 Teacher: Gerald Newton Teacher's Home Page: http://www.electrician2.com Teacher's Email:
[email protected]
No. of Questions= 20
1.
Each commercial building and occupancy accessible to pedestrians shall be provided with at least one accessible outlet for sign or outline lighting. This outlet shall not supply any other load and shall be rated no less than _____, and the load shall be computed at a minimum of _________ volt-amperes. a) 15 amperes , 1200
b) 1500 watts, 1500 c) 20 amperes, 1200 d) 30amperes, 1500 ## CORRECT --> section 600.5 (a) and (b)
2.
In the field, it is not permissible to connect fuses or circuit breakers in parallel. a) True b) False ## CORRECT --> section 240.8
3.
Capacitors that contain more than ______ gallons of flammable liquid shall be enclosed in a vaults or outdoor fenced enclosure. a) 1 b) 2 c) 3 d) 4 ## CORRECT --> Capacitors containing more than 3 gal (11.36 L) of flammable liquid shall be enclosed in vaults or outdoor fenced enclosures .section 460.2 (a)
4.
A grounded circuit conductor shall NOT be permitted to ground noncurrent-carrying metal parts of equipment, raceways, and other enclosures at which of the following locations ____: Service equipment on the supply side of the service disconnecting a) means. On the supply side or within the enclosure of the main disconnecting b) means for separate buildings
On the supply side or within the enclosure of the main disconnecting c) means or overcurrent devices of a separately derived system Ranges and Dryers on the load side of the service disconnecting d) means. ## CORRECT --> section 250.142(a)
5.
Generally, when driving a ground rod into the ground which of the following apply: a) The upper end of the ground rod shall be driven to below grade level. The upper end of the ground rod may be driven to below grade or b) flush with grade but the connection to the grounding electrode conductor shall be accessible. c) The upper end of the ground rod shall be flush with grade. d) The upper end of the ground rod shall be above grade level. ## CORRECT --> Generally speaking, flush or below is the correct Code rule. There are exceptions such as for concrete encased ground rods.section 250.52(c) and 250.68
6.
The Life Safety Branch of a hospital emergency electrical system shall supply power for ________. a) Illumination of Means of Egress b) Exit Signs. c) Alarm and Alerting Systems. d) Communications Systems. e) All of the above and power for the generator set and elevator. ## CORRECT --> section 517.32
7.
In a hospital electrical system, the critical branch of the Emergency System shall supply power for all the following with the exception of _____.
Power for task illumination, fixed equipment, selected receptacles, a) and special power circuits serving the following areas and functions related to patient care. b) Nurse call systems c) Blood, bone, and tissue banks d) Three-phase motors used for the supply water. Single-phase fractional horsepower motors shall be permitted to be e) connected to the critical branch. ## CORRECT --> Only single-phase fractional horsepow er motors are permitted.section 517.33
8.
Auxiliary gutters are permitted to contain all of the below with the exception of ______. a) overcurrent devices. b) conductors c) busbars d) spliced conductors ## CORRECT --> may enclose conductors or busbars but shall not be used to enclose sw itches, overcurrent devices, appliances, or other similar equipment.section 374.1
9.
An insulated conductor used in a switchboard shall be _______. a) listed b) flame retardant rated not less than the voltage applied to other conductors or busbars c) with which it may come in contact. d) All of the above. ## CORRECT --> An insulated conductor used w ithin a sw itchboard shall be listed, flame retardant, and shall be rated not less than the voltage applied to it and not less than the voltage applied to other conductors or busbars w ith w hich it may come in contact.section 384.9
10.
A three phase 480 volt air conditioner shall be connected ________. directly to the premise wiring system using an acceptable method a) from Chapter 3. b) with a 3-prong attachment plug and flexible cord c) with a 4-prong attachment plug and flexible cord d) with flexible cord and plug is not over 4 feet long. ## CORRECT --> Where a flexible cord is used to supply a room air conditioner, the length of such cord shall not exceed 10 ft (3.05 m) for a nominal, 120-volt rating or 6 ft (1.83 m) for a nominal, 208- or 240-volt rating.section 440.64
11.
Cables containing Class 2 circuits can be installed in the same cable tray as power and lighting cables rated 6oo volts without a partition if the Class 2 circuit cables are ________. a) PLTC b) CL2 c) Metal-Clad d) CL3 ## CORRECT --> Permitted w here either (1) all of the electric light, pow er, or (2) all of the Class 2 circuit conductors are in racew ay or in metal-sheathed, metalclad, nonmetallic-sheathed, or Type UF cables.section 725.54(a)(3)
12.
What is the minimum working space WIDTH in front of equipment operating at 120 volts AC containing fuses or circuit breakers that may be serviced while energized? a) 3 feet b) 30 inches c) 4 feet d) None of the above
## CORRECT --> The w idth of the w orking space in front of the electric equipment shall be the w idth of the equipment or 30 in. (762 mm), w hichever is greater.section 110.26(a)(2)
13.
In general, the maximum length that 3/8 inch flexible metal conduit that can be made up in the field is _____. a) 3 feet b) 4 feet c) 6 feet d) None of the above - there is no maximum length. ## CORRECT --> In general, lengths in excess of 6 ft shall be part of a manufactured assembly or w iring system.section 350.10(a);620.21 and 430.145(b)
14.
If structural members are on 5 feet centers EMT can be supported _____ feet from a box instead of within 3 feet when the EMT is run from a box to a structural member and there is no other method to readily fasten the EMT within 3 feet. a) 4 b) 5 c) 6 ## CORRECT --> Fastening of unbroken lengths shall be permitted to be increased to a distance of 5 ft w here structural members do not readily permit fastening w ithin 3 ft.section 348.13 exception # 1
15.
Switches an circuit breakers used as switches shall be installed so that the center of the grip of the operating handle is not more than _____ above the floor or working platform. a) 6 feet 7 inches b) 6 1/2 feet c) 5 feet d) 4 feet
## CORRECT --> They shall be installed so that the center of the grip of the operating handle of the sw itch or circuit breaker, w hen in its highest position, w ill not be more than 6 ft 7 in. above the floor or w orking platform.section 380.8(a)
16.
Where the circuitry is interlocked so as to prevent operation of selected motors or other loads at the same time, the branch circuit conductor ampacity shall be permitted to be based on ______. 125 percent of the largest motor full amperes plus the sum of the other a) motors full load currents. the summation of the currents of the motors and other loads to be b) operated at the same time that results in the highest total current. c) 125 percent of the sum of all the loads. ## CORRECT --> section430.24 exception #3
17.
An insulated grounded conductor larger than No. 6 shall be identified by _____. (Select the best answer) a continuous white or natural gray outer finish or by three continuous white stripes on other than green insulation along its entire length or at a) the time of installation by a distinctive white marking at its terminations. b) By tagging or other effective means. c) By painting the terminals and splices white. d) By applying gray tape to the exposed areas of the conductors. ## CORRECT --> section 200.6(b)
18.
The requirements for attachments plugs and cord caps shall conform to one or more of the following. Select the best answer. No receptacle shall be installed so as to require an energized a) attachment plug as its source of supply. Attachment plugs shall be installed so that their prongs, blades, or pins b) are not energized unless inserted into an energized receptacle.
Receptacles, cord connectors, and attachment plugs shall be constructed so that receptacle or cord connectors will not accept an c) attachment plug with a different voltage or current rating than that for which the device is intended; ex. for 20A T recept. Nongrounding-type receptacles and connectors shall not accept d) grounding-type attachment plugs. e) All of the above ## CORRECT -->section 410.56 (g) and (i)
19.
An outlet box for the tap conductor of a recessed fixture terminal connection shall be placed at a minimum distance of _____ from the fixture. a) 4 feet b) 18 inches c) 1 foot d) None of the above ## CORRECT --> Tap conductors of a type suitable for the temperature encountered shall be permitted to run from the fixture terminal connection to an outlet box placed at least 1 ft from the fixture.section 410.67(c)
20.
When liquidtight flexible metal conduit or flexible metal conduit are installed as a fixed raceway, they shall be SECURED at intervals not exceeding 4 1/2 feet and within 12 inches on each side of every outlet box or fitting. Are tie wraps suitable to secure these raceways? a) Yes, if acceptable to the authority having jurisdiction b) Yes, if approved c) Both A and B d) None of the above; tie wraps cannot be used. ## CORRECT --> The racew ays shall be secured by an approved means. Approved means acceptable to the authority having jurisdiction per Definition in Art 100.artikel 100 definition of aproved and section 350.18 and 351.8
