Metal to metal to metal

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tonype

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Warehouse - crude mezzanine. Switch boxes secured to metal bracket secured to shelving. Light fixtures also secured with metal bolts to floor the metal mezzanine. I just do not have a warm and fuzzy feeling about this with respect to bonding and grounding. Any thoughts would be appreciated.
 

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IMO the issue is the lack of support and fastening of the boxes, raceways, and cables.
 
As long as anything attached that is likely to energize the metal is properly grounded, so is the metal itself.
 
I would be leaning more towards the "Subject to physical Damage" concern.


JAP>
 
The box in the bottom of the picture left of the post has attachment issues too. Is that EMT in a offset nipple in the top opening?
 
tonype said:
Warehouse - crude mezzanine. Switch boxes secured to metal bracket secured to shelving. Light fixtures also secured with metal bolts to floor the metal mezzanine. I just do not have a warm and fuzzy feeling about this with respect to bonding and grounding. Any thoughts would be appreciated.
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Others have pointed out some other issues, but when it comes to metal to metal to metal - that just increase EGC effectiveness. Your wiring methods should still have a stand alone EGC, even if it is a metal raceway itself as the EGC. All that extra metal framing just gives alternate paths for ground faults should you have a failure in an EGC. You do not in any case want improper bonds to a "grounded" current carrying conductor - that leads to stray currents in non desired current carrying paths during normal operation.
 
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