EBCS-10 Ethiopian Building Code Standard Electrical Installation of Buildings

EBCS-10

Ethiopian Building Code Standard

ELECTRICAL INSTALLATION OF BUILDINGS

FOREWORD The Proclamation to define the powers and duties of the Central and Regional Executive Organs of the Transitional Government of Ethiopia No. 41/1993 empowers the Ministry of Works and Urban Development to prepare the Country's Building Code, issue Standards for design and construction works, and follow up and supervise the implementation of same. In exercise of these powers and in discharge of its responsibility, the Ministry is issuing a series of Building Code Standards of general application. The purpose of these standards is to serve as nationally recognized documents, the application of which is deemed to ensure compliance of buildings with the minimum requirements for design, construction and quality of materials set down by the National Building Code. The major benefits to be gained in applying these standards are the harmonization of professional practice and the ensuring of appropriate levels of safety, health and economy with due consideration of the objective conditions and needs of the country. As these standards are technical docum~nts which, by their very nature, require periodic updating, revised editions will be issued by the Ministry from time to time as.appropriate. The Ministry welcomes comments and suggestions on all aspect of the Ethiopian Building Code Standards. All feedback received will be carefully reviewed by professional experts in the field of building construction with a view to possible incorporation of amendments in future editions.

Haile Assegidie Minister Ministry of Works and Urban Development 1995

INTRODUCTION This Code Standard for the Electrical Installation of Buildings is part of the Building Code of Ethiopia: This Code Standard for the Electrical Instaijation of Buildings is mairily adopted from lEE Regulations for Electrical Installations and Canadian Electrical Code, Part 1, to suit the Ethiopian conditions. Other publications quoted are shown in the respective sections of the Code and the Ethiopian Authority for Standardization maintains registers of a number of foreign national and international standards. The Code embr~ces several aspects of electrical installation work and sets standards and provisions for safe utilization of electricity. The Technical Committee for Code Standards for the Electrical Installation of Buildings comprises of the following Institutions representing balanced interest of all segments of the public concerned with the subject matter: • Ministry of Works & Urban Development (MWUD) • Building Design Enterprise ·(BDE) • Ethiopian Electric Light & Power Authority (EELP A) • Addis Ababa University, Faculty of Technology (AAU) • Ethiopian Authority for Standardization (BAS).

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ETHIOPIAN BUILDING CODE STANDARD

EBCS-10 ELECTRICAL INSTALLATION OF BUilDINGS

TABLE OF CONTENTS Section 1 1.1 1.2 1J

Section 2 2.1

2.2

Scope And Definitions Scope Nonnative references Defmitions

1 1 2

Gen~ral Requirements Administrative

20

2.1.1 2.1.2

Authority for rules Pennit

2.1.3 2.1.4 2.1.5 2.1.6 2.1.7

Application for inspection Posting of penn it ', Notification re-inspection Plans and specifications Connection authorization

2.1.8 2.1.9 2.1.10 2.1.11 2.1.12 2.1.13 2.1.14

Re-inspection Renovation of existing installation Use of approved equipment Deviation or postponement Powers of rejection Installation of electrical equipment Damage and interfer•••.• ~e

i ••••••••••••••.••••••••••

i •••

,

20 20 20 20 20 21 21 21 21 22 22 22 22 22

Technical

23

2.2.1 2.2.2

Conventional symbols Co-ordination

'.'

2.2.3 2.2.4 2.2.5 2.2.6

Location and requirement of substation Rooms (spaces) required Location and requirements of distribution boards Location and requirements of PBX/PABX rooms

23 23 23 23 24 24

2.3

2.4

Section 3

Planning and designing 2.3:1 General

25 25

2.3.2 2.3.3

25 25

Marking of equipment 2.4.1 General

" ,

26 26

,

2.4.2

Workmanship and materials

27

2.4.3 2.4.4 2.4.5 2.4.6

Material for anchoring Protection of persons and property Maintainability , Enclosures

27 27 27 28

,. ,.

Illumination

3.1 3.2

Scope Normative references

3.3

Definitions

3.4

Lighting requirements 3.4.1 IllumiQance 3.4.2 Luminance 3.4.3 Glare' 3.4.4 3.4.5

29 29 ,

30 35 35 35 36

" '.. " '

Light direction and modelling Colour rendering

36 , .. , 36

3.5

Emergency lighting requirements 3 .5.1 Escape lighting 3.5.2 Safety lighting for particular hazardous workplaces 3.5.3 Standby lighting

37 37 37 38

3.6

Lighting requirements for various types of buildings 3.6.1 General 3.6.2 Industrial 3'.6.3 Offices.,., 3.6.4 Hotels and restaurants,

38 38 39 39 39

3.7

II

Layout and installation drawing Design

3.6.5

Educational establishments

3.6.6

Hospitals

. ""

'

40

,

Outdoor lighting requirements 3.7.1 Illuminance

'

40

,

,

3.7.2

Colour r~ndering group

3,7.3 3.7.4

Limitation of glare : ' .' Lighting of outdoor fixed location work spaces

42 42 42 , 43 43

Se~tion 4

Conductors

4.1

Scope

4.2

Nonnative references

66

4.3

Definitions

67

4.4

Size of conductors

69

4.5

',' "

66.

4.4.1

Ph~e conductors in a.c. Circuits and live conductors in d.c. circuits ..

69

4.4.2

Neutral conductors

69

,

Ampacity of wires, cables and flexible cords

70

4.5.1

70

Conductor operating temperature

4.5.2 . Cables connected iri parallel

70

4.5.3

Cables connected to bare conductors or busbars

70

'4.5.4

Voltage drop

70

~

4.6

Flexible cords

4.7

Colour of conductors

"

4.8

Maximum permissible temperll,ture

'.'

:

70 71 71

Annex (preface)

74

Annex A (Normative) - Correction factors

85

Annex B (Normative) - Type of cable and ampacity

90

Section 5

Service And Service Equipment

5.i

Scope

5.2

Normative references

5.3

Definitions

5.4

General requirements

5.5

"

141

'.'

141 141

'

"

142

5.4.1

Number of services permitted

142

5.4.2 5.4.3 5.4.4

Consumer's installation not to be supplied through another building .conductors considered outside of a building Other' conductors in raceway or cable·

143 143 144

5.4.5

Clearance from building openings

144

Service equipment 5.5.1 General 5.5.2

Control

144 144 ·.. 145

III

5.6

5.7

Section 6

Wiring methods

148

5.6.1 5.6.2

148 148

Underground consumer's service conductors Overhead consumer's service conductors

Metering equipment 5.7.1 Connection

149 149

Circuit Loading and Demand Factor

6.1 6.2

Scope Normative references

150 150

6.3

Defmitions

150

6.4

General

151

6.5

Section 7

6.4.1

Current calculation

151

6.4.2 6.4.3 6.4.4

Voltage drop Maximum circuit loading Use of demand factor

151 151 151

Services and feeders

151

6.5.1

Single-family dwellings

151

6.5.2 6.5.3

Apartment and similar multi-family buildings Schools

6.5.4

Hospitals

153

6.5.5

Hotels, motels, dormitories, and buildings of similar occupancy

154

6.5.6 6.5.7

Other types of occupancy Branch circuits

155 155

6.5.8

Feeder demand factors for lifts

155

,

152 153

Earthing, Bonding, and Lightning Protection Part I - Earthing, and Bonding

IV

7.1 7.2

Scope Normative references

157 157

7.3

System and circuits earthing

158

7.3.1

Direct current. systems

158

7.3.2

Alternating - current systems

158

7.4

Location of system earthing connections 7.4.1 D.C. systems 7.4.2 A.C. systems 7.4.3 Isolated systems , , , '.' 7.4.4 Single service supply to two or more buildings or structures ., 7.4,5 Conductors to be earthed , , 7.4.6

7,6

7.8

,,

,

, .. 160

Bonding 7.5.1 Non-current carrying metal parts , , , 1.5.2 Exposed non-current-carrying metal parts of equipment •....... 7.5.3 Non-metallic wiring systems 7.5.4 Non-electrical services 7.5.5 Extraneous fixed metalwork

161 161 161 161 161 164

Method of earthing

164

7.6.1 7.6.2 7.6.3 7.6.4 7.6.5 7.6.6 7.7

Current over earthing conductor

159 159 159 1·59 160 160

,

,

Effective earthing Common earthing conductor Common earthing electrode Underground service Short section of raceway Fixed equipment

Bonding methods

,

_ , '. ,

, .. ", \. ,

166

7.7.1

Clean sUifaee

7.7.2 7.7.3 7.7.4

Bonding at service equipment ...........•.............. Means of assuring continuity at service equipment Metal annour or tape of service cable,

7.7.5 7.7.6 7.7.7

Bonding at other than service equipment Loosely jointed metal raceways Bonding jumpers

,

Earthing electrodes .. , 7.8.1 7.8.2 7.8.3

General, , Service pipe electrode, Artificial earthing electrodes

,,.,

164 164 164 165 165 ,. 165

166 166 167

, ,

,.,

, ,

,

166

167 167 167 168 168 168 169

v

7.9

7.10

Section 7

Earthing and bonding conduc;tors

171

7.9.1

General

171

7.9.2 7.9.3 7.9.4 7.9.5 7.9.6

Installation of system earthing conductors Installation of equipment bonding conductors Earthing conductor size for d.c. circuits Earthing conductor size for a.c. system Bonding conductor size

172 173 174 174 174

Earthing and bonding conductor connections

175

7.10.1 7.10.2 7.10.3 7.10.4 7.10.5

175 175 175 176 176

Bonding. conductor connection to raceways Earthing conductor connection to water pipe electrodes Earthing conductor connections to other than water pipe electrodes Bonding conductor connection to circuits and equipment Earthing conductor cQJ111Cction to electrodes

Earthing, Bonding and LightninlZProtection Part n- pghtning Protection

7.11 Scope 7.12 Normative references 7.13 Definitions 7.14 Materials 7.14.1 General 7.14.2 7.14.3 7.14.4 7.14.5 7.15 Form 7.15.1 7.15.2 7.15

J

7.16

..

Galvanic compatibility Corrosion protection Mechanical protection Use of aluminium

.'

178 178 179 180 180 180 181 181 181

,

and size Air termination Conductors Earth termination

184 184 185 185

7.15.4 Minimum dimension

185

Air termination 7.16.1 General

185 185

7.16.2 Support 7.16.3 Metallic projections 7.16.4 Metallic materials

185 185 186

7.16.5 Structure within zone .of protection ' 7.16.6 Air termination on roof 7.16.7 Air termination on reinforced concrete structure

186 186 186

VI

!

7.17

Down conductor

,

7,17.1 General

,

"

,

7.17.2 Routing 7,17.3 Recommended number

186

'

186 ,

187 187

,.,

7.17.4 Mechanical protection 7.17.5 Corrosive soil .....•............................... 7.17.6 External routes not available

187 187

,

7.17 .7 Lift shafts

, .. ,

,

,,. ,

7.17.8 Re-entrant loops . , Bonding to prevent side flashing Bonds

7.17.12

Testpoints

Earth termination

188 188 188

'

,

:

189

..........................•............

7.18.1 Termination, 7.18,2 Resistance to earth

7.19

188

,

7.17.10 7.1 7.11

190 , '

,

7.18.3 Earth electrodes.

,

7.18.4 Connection point

.. ,.".',

Common earthing

,

,

190 , . 190

,

, . , .. ,

, . , .. , ,

,

190 ,

:.,

190

,

7.19.1 Common earth potential

192

,

192

7.19.2 Common earth bonding

, . , . 192

7.20 Use of reinforcement for earthing in concrete Structures .. , .. : .. , 7.20.1 General, , , ,', . , . , , ,, 7.20.2 Electrical continuity . , . , -7.20.3 Prestressed concrete members 7.20.4 Precast concrete members 7.21

,, '

,

".,. 194 " . , . 194 194 194

'

, ,

,.,

193 193

, .. , , , .. , .. 193 193 "" .. , .. 193

,

Structural ~teel framing for lightning protection 7.21.1 General '.' 7.21.2 Air termination ,.,., 7.21.3 Connection ' , 7.21.4 Earthing .. , 7.21.5 Interconnection

187 188

'.'

7.17,9 Sharp bends

7.18

"

'

, 194 194

Annex (Informative) Annex A - System design Annex B - Consultation

, .. ,

219 220

VII

Section 8

Wiring Methods

8.1 8.2

Scope Normative reference

8.3

General requirements 8.3.1 Methods of-installatiOns 8.3.2 Wiring in ducts and plenum chambers 8.3.3 Underground installations 8.3.4 Conductors in hoistways

8.4

8.5

8.6

Conductors

8.9

223

223 224 224 225

,

······················

226

Types of conductors Radii of bends in conductors Conductor joints and splices

226 226 227

8.4.4

Supporting of conductors

228

Open wiring

228

8.5.1 Open and clipped direct 8.5.2 Spacing of conductors 8.5.3 Conductor supports

228 228 229

8.5.4

22?

Spacing of supports

Exposed wiring on exterior of buildings and between Buildings on the same premises

Location of conductors Clearance of conductors Power supply conductors

Bare bus bars and risers Installation of boxes, cabinets, outlets and terminal fittings 8.8.1 Number of outlets per circuit 8.8.2 Outlet boxes 8.8.3 Conductors in boxes 8.8.4 Terminal fittings Cables, conductors and wiring methods

Annex A (Normative): Schedule of methods of installation of cables

VIII

223 223

8.4.1 8.4.2 8.4.3

8.6.1 8.6.2 8.6.3 8.7 8.8

······················

,

229 229 229 229 230 230 230 231 231 ·231 232 233

Section

® 9.1 9.2

9.3

; 9.4

./I

Protection

and Control

Scope Normative references

'

237 237

General requirements 9.3.1 Protective and control devices

237 237

9.3.2

238

Types and ratings of protective and control devices

Protective devices

238

9.4.1

Overcu.rrent devices

238

9.4.2

Earth fault protection

239

9.5

Fuses

240

9.6

Circuit breakers

240

9.7

Control devices

240

9.8

Switches

241

9.9

Protection and control of miscellaneous apparatus

241

Section 10

Class 1 and Class 2 Circuits

10.1 Scope 10.2 Normative references 10.3 Classification

245 245' .10.

•••••••••••••••••••••

\

245

••••••••

10.3.1 General 10.3.2 Class 1 extra-low-voltage

245 power circuits

246

10.3.3 Class 2 low-energy power circuits 10.3.4 Hazardous location

246 246

10.3.5 Circuits to safety control devices 10.3.6 Circuits in communication cables

246 246

\

10.4 Class 1 circuits

247

10.4.1 Limitation of Class 1 circuits

247

10.4.2 Methods of installation for Class 1 circuits

247

10.4.3 Overcurrent protection of Class 1 circuits 10.4.4 Location of overcurrent devices in Class 1 circuits .;

247 247

10.4.5 Class I extra-low-voltage power circuit ~ources including Transfonners 10.4.6 Conductor material and sizes

. 248

248

10.4.7 Insulated conductors for Class 1 wiring "

248

10.4.8 Conductors of different circuits in the ,same enclosure, cable, or Raceway 10.4.9 Mechanical protection of remote-control circuits

248 249

10.4.10

249

Class 1 circuits extending aerially beyond a building

IX

10.5 Class 2 circuits 10.5.1 Limitations of Class 2 circuits

,

249 249

10.5.2 Methods of installation on supply side of overcurrent Transformers or other devices for Class 2 circuits

protection

10.5.3 Marking 10.5.4 Overcurrent protection for Class 2 circuits 10.5.5 Location of over current devices

or 250 250 250 251

'"

10.5.6 Conductors for Class 2 circuit wiring 251 10.5.7 Separation of Class 2 circuit conductors from other circuits 251 10.5.8 Conductors of different Class 2 circuits in the same cable, enclosure, or raceway 252 10.5.9 Penetration ofa fire separation 252 10.5.10 Conductors in vertical shafts and hoistways ; . 252 10.5.11 10.5.12

Class 2 conductors and equipment in ducts and plenum chambers .. 252 Equipment located on the load side of overcurrent protection, transformers, or current-limiting devices for Class 2 circuits , , , 252

10.5.13 10.5.14

Class 2 circuits extending beyond a building Underground installations ,

253 253

,

Section 11 Installation of Electrical Equipment 11.1 Scope 11.2 Normative references 11.3 General

254 254 , 254

, .. ,

11.3.1 Fusible equipment 11.3.2 Connection to identified terminals or leads 11.3.3 Equipment over combustible surfaces 11.3.4 Installation of ventilated enclosures 11.3.5 Outdoor installations 11.4 Electric heating and cooking appliances 11.4.1 Location of non-portable appliances 11.4.2 Rating of portable appliances 11.4.3 Appliance exceeding 1500w 11.5 Heatingequipment ; 11.6 Submersible pumps 11.7 Motors and associated ,circuits 11.7.1 11.7.2 11.7.3 11.7.4 11.7.5

Wiring methods and conductors Overcurrent protection Overload and overheating protection Undervoltage protection ~ Control

11.7.6 Disconnecting means

x

'

,

254 25~ ".

255 255 255 255 255 255 256 , 256 256 257 257 260 262 265 266 267

11.8 Air conditioning and refrigerating equipment 11.8.1 General

'.'

268 268

11.82 Branch circuit

268

11.8.3 Disconnecting means

269

11.8.4 Supply cords

,

269

11.9 Storage batteries

','

269

11.9.1 Location of storage batteries

269

11.9.2 Ventilation of battery rooms or areas

269

11.9.3 Battery vents

269

11.9.4 Battery instillatio~

'

269

11.9.5 Wiring

; .......•...

270

Section 12 Hazardous Locations 12.1 Scope 12.2 Nonnative reference 12.3 Classification

,

12.3.1 Division of Class I locations

;

279 279 279

...............•............

279

12.3.2 Division of Class II locations

280

12.3.3 Division of Class III locations

281

12.4 General requirements

281

12.4.1 Electrical equipment 12,.4.2 Marking .. "

281 282

12.4.J Non-essential electrical equipment

283

12.4.4 Equipment rooms

'

12.4.5 Cable trays

283 ; 284

12.5 Class I locations

284

12.5.1 Installations in Class I, Division 1 locations

284

. 12.5.2 Installat~ons in Class I, Division 2 locations

286

12.6 Class II locations

'.'

12.6.1 Installations in Class II, Division 1 locations 12.6.2 Installation in Class II, Division 2 locations ...............• 12.7 Class III locations

287 287 ~ 289 290

12.7.1 Installations in Class III, Division 1 locations

290

12.7.2 Installations in Class III; Division 2 locations

293

XI

Section 13 Fhimmable Liquid Dispensing and Service Stations, Garages, Bulk Storage Plants, Finishing Processes and Aircraft Hangars 13.1 Scope 13.2 Nonnative references 13.3 Gasoline dispensing and service stations 13.3.1 Hazardous areas

294 295 295 295

13.3.2 Wiring and equipment within hazardous areas

296

13.3.3 Wiring and equipment above hazardous areas

297

13.4 Commercial garages, repairs and storage 13.4.1 Hazardous areas 13.4.2 Wiring and equipmentin

297 297

hazardous areas

298

13.4.3 Wiring above hazardous areas

298

13.4.4 EqUIpment above hazarqous areas

298

13.5 Residential storage garages 13.5.1 Non-hazardous location.

0

0

298 298

••••••••••••••••••••••••••••

13.5.2 Hazardous location . ;

299

13.5.3 Wiring

:

13.6 Bulk storage plants

299

'

299

13.6.1 , Hazardous areas

:

.

, ..

0

.'

299

•••••••••••••••••••••

13.6.2 Wiring and' eq~ipment in hazardol,ls areas 13.6.3 Wiring and equipment above hazardous areas 13.7 Finishing processes 13.7:1 Hazardous locations

302 302 302 302

0' ••••••••••••••••••••••••••••••••

,0

•••

·•..••

; •••••••.••.••••......

13.7.2 Wiring and' equipment in hazardous areas

304

13.7.3 Wiring and equipment aqove .hazardous areas 13.8 Aircraft; hangars .:. 13.8.1 Hazardous areas.. .. ... . 13.8.2 Wiring .and equipment in ,hazardous 'areas ... 13.8.3 Wiring not within' hazardous area. " '.' 13.8.4 Equipment-not within hazardous' areas 0

••••

0

0

••••••••••

.'

.'

o'

•••••

0

0

•••••

•••

0

'.

0

0

••

0

•••••••••

•••••••••••••••••

••

0.'

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••••

0

•••••••••••••••••••

0

•

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,

'0'

' •••••••••••••

o.

0

:

0 ••••••••••

•••••••••••••

305 305 305 306 306 307

Section 14' Patient Care' Areas 14.1 Scope· , 14.2 Nonnative references 0

XII

•••

' •••••

,;

'

••••••••••

:

,

••••

0

,

•••••••••••••

308 308

14.3 Definitions

308'

14.4 Circuits in basic care areas

31

14.4.1 Branch circuits

'...•..

14.4.2 Bonding to earth in basic-care areas '

'.' .:

'

14.5 Circuits in intermediate and critical-care areas

313

14.5.2 Bonding to earth in intermediate and critical-care areas 14.5.3 Receptacles in intermediate-and critical-care areas 14.6 Isolated systems

'.'

'

14.6.1 Sources of supply 14.6.2 Single-phase isolated circuits

14.7 Essential electrical systems

313 313 314

"

, ,

14.6.3 Three-phase isolated systems

314 314

:

\

315

'

315

14.7.1 Circuits in essential electrical systems .. ,\

Section

312 313

14.5.1 Branch circuits

14.9 Emergency supply

311 ,311

14.4.3 Socket outlets in basic-care areas

14.8 Transfer switches

~

315

,'

316 ,

316

15 Installation of Lighting Equipment 15.1 Scope

:

15.2 Normative references 15.3 Interior lighting :quipment : 15.3.1 General '

"

3 18

, . :.' .. '.' . "

'.'

318

, . '.. ~.~.. ,

318 318

..........•..............

320

'

15.3.2 Location of lighting equipment· 15.3.3 Installation. of ligpting equipment 15.3.4 Wirin~ of lighting. equipment

' .'

323

~

323

15.3.5 Earthing of-lighting equipment :." 15.3.6 Electric-discharge lighting systems operating at 1000V or less ·15.4 q~tdoor lighting equipment 15..4.1 General,

'.' .,

,

:

15.4.2: Permanent outdoor floodlighting installation 1,5.4.3 'Exposedwirin~ for permanent outdoor lighting Annex A (Normative) .'

i

; .. ,

;

326 326 327 327 328 331 334

XIII

Section 16 Fire Alarm System and Fire. Pumps 16.1 Scope , , 16.2 Normative references 16.3 Definitions

'

",.,

16.4 Design consideration , 16.4.1 General ,

,:,.

~ ,

, -,'

.. , ,

,, ., ~

.

16.4.2·