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Subchapter 5. Electrical Safety Orders
Group 1. Low-Voltage Electrical Safety Orders
Article 70. Theaters and Similar Locations

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§2552.53. Construction.

Portable switchboards for use on stages shall comply with (a) through (j) below:

(a) Enclosure. Portable switchboards shall be placed within an enclosure of substantial construction, which shall be permitted to be so arranged that the enclosure is open during operation. Enclosures of wood shall be completely lined with sheet metal of not less than No. 24 MSG and shall be well galvanized, enameled, or otherwise properly coated to prevent corrosion or be of a corrosion-resistant material.

(b) Live Parts. There shall be no exposed live parts within the enclosure.

EXCEPTION: For dimmer faceplates as provided in (e) below.

(c) Switches and Circuit Breakers. All switches and circuit breakers shall be of the externally operable, enclosed-type.

(d) Circuit Protection. Overcurrent devices shall be provided in each ungrounded conductor of every circuit supplied through the switchboard. Enclosures shall be provided for all overcurrent devices in addition to the switchboard enclosure.

(e) Dimmers. The terminals of dimmers shall be provided with enclosures, and dimmer faceplates shall be so arranged that accidental contact cannot be readily made with the faceplate contacts.

(f) Interior Conductors. All conductors within the switchboard enclosure shall be stranded and approved for an operating temperature of 200oC (392oF).

Each conductor shall have an ampacity at least equal to the rating of the circuit breaker, switch, or fuse which it supplies.

EXCEPTION: Conductors for incandescent lamp circuits having overcurrent protection of not over 20 amperes.

Conductors shall be enclosed in metal wireways or be securely fastened in position and shall be bushed where they pass through metal.

(g) Pilot Light. A pilot light shall be provided within the enclosure and shall be so connected to the circuit supplying the board that the opening of the master switch will not cut off the supply to the lamp. This lamp shall be on an independent circuit having overcurrent protection rated or set at not over 15 amperes.

(h) Supply Connections. The supply to a portable switchboard shall be by means of Type S, SO, ST, or STO flexible cord terminating within the switchboard enclosure or in an externally operable fused master switch or circuit breaker. The supply cable shall have sufficient ampacity to carry the total load connected to the switchboard and shall be protected by overcurrent devices.

EXCEPTION: No. 1: Supply Conductors Not Over 10 Feet Long. In cases where supply conductors do not exceed 10 feet in length between supply and switchboard or supply and a subsequent overcurrent device, the ampacity of the supply conductors shall be at least one-quarter of the ampacity of the supply overcurrent protection device where all of the following conditions are met:

a. The supply conductors shall terminate in a single overcurrent protection device that will limit the load to the ampacity of the supply conductors. This single overcurrent device shall be permitted to supply additional overcurrent devices on its load side.

b. The supply conductors shall not penetrate walls, floors, or ceilings, or be run through doors or traffic areas. The supply conductors shall be adequately protected from physical damage.

c. The supply conductors shall be suitably terminated in an approved manner.

d. Conductors shall be continuous without splices or connectors.

e. Conductors shall not be bundled.

f. Conductors shall be supported above the floor in an approved manner.

EXCEPTION: No. 2: Supply Conductors Not Over 20 Feet Long. In cases where supply conductors do not exceed 20 feet in length between supply and switchboard or supply and a subsequent overcurrent protection device, the ampacity of the supply conductors shall be at least one-half the rating of the supply overcurrent protection device where all of the following conditions are met:

a. The supply conductors shall terminate in a single overcurrent protection device that will limit the load to the ampacity of the supply conductors. This single overcurrent device shall be permitted to supply additional overcurrent devices on its load side.

b. The supply conductors shall not penetrate walls, floors, or ceilings, or be run through doors or traffic areas. The supply conductors shall be adequately protected from physical damage.

c. The supply conductors shall be suitably terminated in an approved manner.

d. The supply conductors shall be supported in an approved manner at least 7 feet above the floor except at terminations.

e. The supply conductors shall not be bundled.

f. Tap conductors shall be in unbroken lengths.

(i) Cable Arrangement. Cables shall be protected by bushings where they pass through enclosures and shall be so arranged that tension on the cable will not be transmitted to the connections.

(j) Terminals. Terminals to which stage cables are connected shall be so located as to permit convenient access to the terminals.

(Title 24, Part 3, Section 520-53.)

NOTE: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.

HISTORY

1. Editorial correction filed 11-2-83 (Register 83, No. 45).

2. Amendment filed 8-27-86; effective thirtieth day thereafter (Register 86, No. 37).

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