Lecture 4 Requirements for Electrical Installation 2

Shop Practice with Electrical Code: Requirements for Electrical Installation Part 2 Jayson Bryan E. Mutuc, REE, RME BSEE-PUP MSEE, Major in Power Systems -MIT (candidate)

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Article 1.10 – Requirements for Electrical Installation Part 2 600V, NOMINAL, OR LESS 1.10.2.1 Spaces About Electrical Equipment (p.42) For the purpose of safe operation and maintenance of equipment, access and working space must be provided about all electrical equipment. (a) Working Space Equipment that may need examination adjustment, servicing or maintenance while energized must have working space provided in accordance with (1),(2), and (3): (1) Depth of Working Space The working space which is measured from the enclosure front must not be less than the distance contained in Table 1.10.2.1(a)(1)

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Article 1.10 – Requirements for Electrical Installation Part 2 600V, NOMINAL, OR LESS Table 1.10.2.1(a)(1) Working Spaces Nominal Voltage to Ground

Minimum Clear Distance (mm) Condition 1

Condition 2

Condition 3

0 – 150

900

900

900

151 - 600

900

1000

1200

Condition 1 – Exposed live parts on one side of the working space and no live or grounded parts on the other side of the working space, or exposed live parts on both sides of the working space that are effectively guarded by insulating material. Condition 2 – Exposed live parts on one side of the working space and grounded parts on the others side of the working space. Concrete, brick, or tile walls shall be considered as grounded Condition 3 - Exposed live parts on both sides of the working space

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Article 1.10 – Requirements for Electrical Installation Part 2 600V, NOMINAL, OR LESS a. Dead-Front Assemblies Working space shall not be required in the back or sides of assemblies, such as dead-front switchboards or motor control centers, where all connections and all renewable or adjustable parts, such as fuses or switches, are accessible from locations other than the back or sides.

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Article 1.10 – Requirements for Electrical Installation Part 2 600V, NOMINAL, OR LESS b. Low Voltage By special permission, smaller working spaces shall be permitted where all exposed live parts operate at not greater than 30 volts rms, 42 volts peak or 60 volts dc

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Article 1.10 – Requirements for Electrical Installation Part 2 600V, NOMINAL, OR LESS (2) Width of Working Space (p.44) The width of the working space in front of the electric equipment shall be the width of the equipment or 750mm, which ever is greater. In all cases, the work space shall permit at least a 90 degree opening of equipment doors or hinged panels

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Article 1.10 – Requirements for Electrical Installation Part 2 600V, NOMINAL, OR LESS

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Article 1.10 – Requirements for Electrical Installation Part 2 600V, NOMINAL, OR LESS (3) Height of Working Space (p.44) The work space shall be clear and extend from the grade, floor, or platform to the height required by 1.10.2.1(e) [2000 mm]. Within the height requirements of this section, other equipment that is associated with the electrical installation and is located above or below electrical equipment shall be permitted to extend not more than 150 mm beyond the front of the electrical equipment.

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Article 1.10 – Requirements for Electrical Installation Part 2 600V, NOMINAL, OR LESS

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Article 1.10 – Requirements for Electrical Installation Part 2 600V, NOMINAL, OR LESS (b) Clear Spaces (p.44) Working space is required by this section shall not be used for storage. When normally enclosed live parts are exposed for inspection or servicing, the working space. If in passageway or general open space, shall be suited guarded.

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Article 1.10 – Requirements for Electrical Installation Part 2 600V, NOMINAL, OR LESS (c) Entrance to Working Space (p.4445) (1) Minimum Required. At least one entrance sufficient area shall be provided to give access to working space about. (2) Large Equipment . For equipment rated 1200 amperes or more that contains overcurrent devices, switching devices, or control devices, there shall be one entrance to the required working space not less than 600 mm wide and 2000 mm high at each end of the working space. 11

Article 1.10 – Requirements for Electrical Installation Part 2 600V, NOMINAL, OR LESS a. Unobstructed Exit. (p.45) Where the location permits a continuous and unobstructed way of exit travel, a single entrance to the working shall be permitted. b. Extra Working Space. (p.45) Where the depth of the working space is twice, a single entrance shall be permitted. It shall be located so that the distance from the equipment to the nearest edge of the entrance is not less than the minimum clear distance.

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Article 1.10 – Requirements for Electrical Installation Part 2 600V, NOMINAL, OR LESS (d) Illumination (p.45) Illumination shall be provided for all working spaces about service equipment, switchboards, panelboards, or motor control centers installed doors. The illumination shall not be controlled by automatic means only.

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Article 1.10 – Requirements for Electrical Installation Part 2 600V, NOMINAL, OR LESS (f) Dedicated Equipment Space (p.45) All switch boards, panelboards, distribution boards, and motor control centers shall be located in dedicated space and protected from damage. (1) indoor (p.46) a. Dedicated Electrical Space. The space equal to the width and depth of the equipment and extending from the floor to a height of 1800 mm above the equipment or to the structural ceiling, whichever is lower, shall be dedicated to electrical installation. No piping, ducts, leak protection apparatus, or other equipment foreign to the electrical installation shall be located in this zone.

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Article 1.10 – Requirements for Electrical Installation Part 2 600V, NOMINAL, OR LESS b. Foreign Systems. (p.46) The area above the dedicated space shall be permitted to contain foreign systems, provided protection is installed to avoid damage to the electrical equipment from condensation, leaks or breaks in such foreign systems

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Article 1.10 – Requirements for Electrical Installation Part 2 600V, NOMINAL, OR LESS Locked Electrical Equipment Rooms or Enclosures. Electrical equipment rooms and enclosures housing electrical equipment can be controlled by locks because they are still considered to be accessible to qualified persons who require access

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