No ground wire in panel feeder(s)

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bnbowen@uiuc.edu

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We are in the early design stage for replacing an elevator in 1960's school. We have a 277/480 volt panel in the elevator machine room fed from a 400 amp distribution panel. The 400 amp distribution panel is fed from a larger panel at the service entrance. The elevator requires a ground wire. The problem is, there is no ground wire in the conduit to either panel. Just RGS. Is it permissible to install ground bushings and jumpers inside the panels to properly ground the panels per 517.19(D) and have a compliant design? Thanks for your help once again.
 
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bnbowen@uiuc.edu

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I feed so dumb.

I feed so dumb.

I feel sooooo stupid! I looked up "Panelboards", "Grounding" in the index and one entry was 517.19(D). I didn't notice the "Health Care Facilities" at the top of the page. I checked "Feeders", "Grounding" and went to section 214.6 which sent me to 250.134. 250.134 (A) sent me to 250.118. Does 250.118 mean I can just use the RGS as a ground and not have to pull a wire all the way back? I think I'm missing something here. Please explain. Thanks again!
 
augie47

augie47

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Location
Tennessee
Occupation
State Electrical Inspector (Retired)
In our State, elevator installations are inspected by specialized folks so I have limited inspection experience on them, however, I see nothing in Article 620 that requires grounding of your feeder beyond the normal Code rules and
250.117 recognizes your RGS conduit as an equipment grounding conductor.
When you say "the elevator requires a ground", it appears the NEC finds the conduit acceptable. If you have engineered drawings or other specs requiring an individual conductor that would need to be addressed with the agency requiring it.
I would take into consideration the age and condition of the conduit.
 
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