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Subchapter 5. Electrical Safety Orders
Group 2. High-Voltage Electrical Safety Orders
Article 6. Grounding (Formerly Article 55)

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§2743. Grounding of Systems Supplying Portable High-Voltage Equipment.

(a) Portable high-voltage equipment shall be supplied from a system having its neutral grounded through an impedance.

Where a delta-connected high-voltage system is used to supply portable equipment, a system neutral shall be derived.

(b) Exposed non-energized metal parts of portable equipment shall be connected by a continuous ground return conductor to the point at which the system neutral impedance is connected to earth.

(c) The product of the maximum ground fault current and the impedance of the ground return conductor shall be such as to limit the voltage developed between the portable equipment frame and ground (by the flow of ground fault current) to not more than 100 volts.

(d) Ground fault detection and relaying shall be provided to automatically de-energize any high-voltage system component which has developed a ground fault. The continuity of the equipment ground return conductor shall be continuously monitored so as to de-energize automatically the high-voltage feeder to the portable equipment upon loss of continuity of the ground return conductor.

(e) The grounding electrode to which the portable equipment system neutral impedance is connected shall be isolated from and separated in the ground by at least 20 feet from any other system or equipment grounding electrode, and there shall be no direct connection between the grounding electrodes, such as buried pipe, fence, etc.

(f) High-voltage trailing cables and couplers for interconnection of portable equipment shall be the type approved for the purpose. See Article 14.

NOTE: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.


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

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