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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 and Circuits.

If high voltage systems are grounded, they shall comply with all applicable provisions of other sections of this Article as supplemented and modified by the following requirements:
(a) Systems supplying portable or mobile high voltage equipment, other than substations installed on a temporary basis, shall comply with the following:
(1) The system shall have its neutral grounded through an impedance.
Where a delta-connected high-voltage system is used to supply the equipment, a system neutral shall be derived.
(2) Exposed non-current-carrying metal parts of portable and mobile equipment shall be connected by an equipment grounding conductor to the point at which the system neutral impedance is grounded.
(3) 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 grounding 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 equipment grounding conductor.
(4) 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 (6.1 m) 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.
(b) All Noncurrent-carrying metal parts of all portable and fixed equipment including their associated fences, housings, enclosures, and supporting structures, shall be grounded.
Exception: Equipment that is guarded by location and isolated from ground need not be grounded.Equipment that is guarded by location and isolated from ground need not be grounded.
(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) 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).
2. Amendment of section heading, section and Note filed 4-1-2009; operative 4-1-2009. Submitted to OAL for printing only pursuant to Labor Code section 142.3 (Register 2009, No. 14).

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