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Subchapter 5. Electrical Safety Orders
Group 2. High-Voltage Electrical Safety Orders
Article 6. Grounding

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§2742.1. Grounding of Supports, Enclosures and Equipment.

(a) The following shall be permanently and effectively grounded before the associated high-voltage equipment is energized.

 (1) Metal conduit, cable armor, metal cable trays, metal raceways, and other metal raceways or enclosures for conductors. 

 EXCEPTION for Section 2742.1(a)(1): 

 Metal enclosures such as sleeves that are used to protect cable assemblies from physical damage need not be grounded. 

 (2) Lightning arrester ground terminals and such other equipment. 

(b) Exposed noncurrent-carrying metal parts of fixed equipment that may become energized shall be grounded under any of the following conditions:

 (1) If within 8 ft. (2.44 m) vertically or 5 ft. (1.52 m) horizontally of ground or grounded metal objects and subject to employee contact; 

 (2) If located in a wet or damp location and not isolated; 

 (3) If in electrical contact with metal; 

 (4) If in a hazardous (classified) location; 

 (5) If supplied by a metal-clad, metal-sheathed, or grounded metal raceway wiring method; or 

 (6) If equipment operates with any terminal at over 150 volts to ground. 

 EXCEPTIONS for Section 2742.1(b): 

 Exposed noncurrent-carrying metal parts of the following types of fixed equipment need not be grounded: 

 1. Enclosures for switches or circuit breakers used for other than service equipment and accessible to qualified persons only. 

 2. Distribution apparatus, such as transformer and capacitor cases, mounted on wooden poles, at a height exceeding 8.0 ft. (2.44 m) above ground or grade level. 

 NOTE: Clearances prescribed by the California Public Utilities Commission shall apply where applicable if more protective. 

(c) Effective grounding of all equipment shall be assured by the use of an equipment grounding conductor, where feasible, such that the path to ground will:

 (1) Be permanent, and continuous. 

 (2) Have ample ampacity to conduct safely any currents liable to be imposed upon it. 

 (3) Have impedance sufficiently low to limit the potential above ground, and to facilitate the operation of the overcurrent or ground fault detecting devices in the system. Where the conduit is intended to function as the equipment grounding conductor, approved threaded couplings, hubs, and joints, or double locknuts and bushings with bonding jumpers are required. 

(d) Where high-voltage equipment and associated metal enclosures or structures are intentionally isolated from ground, provision shall be made to prevent any person who can make contact with ground from contacting the isolated equipment and associated metal enclosures or structures when such equipment is energized. Intentional grounds shall be applied after such equipment is de-energized and before access is permitted, in accordance with Work Procedures, Article 36.

<General Materials (GM) - References, Annotations, or Tables>

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

1. New section filed 4-1-2009; operative 4-1-2009. Submitted to OAL for
printing only pursuant to Labor Code section 142.3 (Register 2009, No.

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