equipment ground

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rbarbrey

Member
Are device boxes grounded back to service through the metal conduit or equipment ground conductor, and the device itself.(Receptacle, switch)?
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Re: equipment ground

If an equipment grounding conductor is present in a metal box and is spliced or connected to a device within the box, than it must be connected to the box even if the box were fed with a grounded metallic raceway. (This wouldn't apply to an IG conductor). You couldn't feed a metal box with NM cable and simply terminate the ground wire on the device. You would be required to connect the equipment grounding conductor to the box as well as to the device as in 250.146.
See also 250.148
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Re: equipment ground

250-146(A) allows metal-to-metal contact between the device yoke and the box for surface-mounted boxes, and even for cover-mounted devices if the parts are listed for such.

250-146(B) allows for the device-mounting screws to provide the continuity if designed and listed for such, even in flush-mounted (in-wall) boxes.
 
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