Power panel as means of grounding path.

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jimej4

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Need your help,
We recently opened up an old 3 phase panel all the grounds coming into it are on individual set screw lugs bolted to the back of the panel
and there is no grounding bar.
I've seen it in the NEC where you can't use the Panel as a grounding path but I just can't find it.
I would be grateful for your help.
Thanks
 
Are you thinking the neutral conductor? ..408.41

In either case the lug is probably not suitable for more than 2 conductors.
 
What code provison says you can use the panel enclosure, or any other enclosure for that matter, as an EGC?
 
don_resqcapt19 said:
250.118 lists the things are may be used as EGCs...I don't see enclosures on that list.
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I agree with you but lets not confuse the OP, it is an accepted trade practice to use the enclosure as an EGC.

It happens at each box in a system that uses the raceway as the EGC.
 
I don't think that an enclosure would be on the list, because it is not a conductor, it is an enclosure.

Enclosures have been used to connect between EGC's since day one.

Anytime you use conduits as a EGC and it connects to the enclosure, the enclosure becomes part of the EGC.
 
don_resqcapt19 said:
I don't see anything in either of those sections that says the panel enclosure is permitted to be used as an EGC.
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I think 250.4(A)(3) is clear about it.

3) Bonding of Electrical Equipment. Normally non–current-carrying conductive materials enclosing electrical conductors or equipment, or forming part of such equipment, shall be connected together and to the electrical supply source in a manner that establishes an effective ground-fault current path.
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408.40 Grounding of Panelboards.
Panelboard cabinets and panelboard frames, if of metal, shall be in physical contact with each other and shall be connected to an equipment grounding conductor. Where the panelboard is used with nonmetallic raceway or cable

or where separate equipment grounding conductors are provided, a terminal bar for the equipment grounding conductors shall be secured inside the cabinet.



The terminal bar shall be bonded to the cabinet and panelboard frame, if of metal; otherwise it shall be connected to the equipment grounding conductor that is run with the conductors feeding the panelboard.
 
tkb said:
I think 250.4(A)(3) is clear about it.
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I don't see how telling me to bond it is the same as telling me that I can can use it as an EGC.
I agree that it is done every day and even the design of the equipment grounding bar that is used with enclosures uses the enclosure as the conductor. I just don't see anything in the code that actually says we can do it that way. I see no hazard or safety issue in using the enclosure as an EGC assuming a proper connection has been made to the enclosure.
 
I was always told that the NEC is a permissive code and if the action is not restricted by the code, it is allowed.
 
tkb said:
I was always told that the NEC is a permissive code and if the action is not restricted by the code, it is allowed.
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I agree, but it remains my opinion that the list of permitted EGC in 250.118 is such a restriction.
 
I may be wrong but I think the OP is talking/thinking about when the grounded conductor is landed in the wrong place and using the bonding screw or cabinet to complete the path. Don't have my book handy for the code reference.
 
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