Cabinet bonding

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RichB

RichB

Senior Member
Location
Tacoma, Wa
Occupation
Electrician/Electrical Inspector
Morning everybody,

I need you to help me out again,,,

We have several cabinets that have a gasketed, removable panel that our contractor brought his conduits thru.

He did not use a grounding bushing on the conduit, the bolts that hold the panel on do not cut through the paint and the lock nuts do not cut the paint to what we ( myself andf the other inspectors) would consider enough to be used as a bond.

So, we feel that there is NOT a bond between the conduit, panel and the rest of the system. We are asking for a bonding bushing and a jumper, and the contractor is saying no.

I know I have seen something, either in the Bonding/Grounding class or read it in the NEC but casn't find it and I don't have enough hair left to keep tearing out!!LOL

My question is--do any of you have a reference for requireing how the removable panel and conduit are to be bonded?

Thanks again folks!!

Rich
 
A little more detail on exactly what is meant by removable may be necessary.

Is this something that is frequently installed and removed, as in completely taken out and not part of the operation when it is out though the equipment still can operate without it in some capacity?

Is it something that normally would be installed and left in place but is still able to be removed on a rare occasion?

Is it something that is hinged and gets moved but not exactly "removed" regularly?
 
RichB said:
Morning everybody,

We have several cabinets that have a gasketed, removable panel that our contractor brought his conduits thru.

Rich
Click to expand...

Is he bringing it through the cover or the cab? Got a picture by any chance?
 
DOn't have a picture yet--

Picture a cabinet 4 feet wide and 3 feet deep-- there are "covers or panels" with a neoprene seal screwed to the top with # 10 machine screws--These are not normally removed after installation-and the conduits are brought down and run through the "cover" and not the solid part of the top.

I should have pics in a day or so--hopefully today

Thanks!!
 
here are the pics--I think it needs a bonding jumper
 

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I would agree with your concerns. The screws could possibly bond around the gasket but that does not address your other concerns.

Tell him to buy a split bonding bushing. This isn't that hard.
 
I think one can make an argument that it is an inadequate bond due to lack of thread engagement. However, if he were to remove one screw and grind the paint off on both sides, and then reinstall it, I think it would be hard to argue that would be inadequate.
 
RichB said:
here are the pics--I think it needs a bonding jumper
Click to expand...
I myself would be ok with bonding bushings on the raceways. The filler panel may or may not be sufficiently bonded via the mounting screws, but I don't want to make that determination. I do think it is better bonded then what you sometimes see with reducing washers.
 
petersonra said:
what difference does it make if continuity is provided by the screws?
Click to expand...
If continuity is provided only by the screws then those screws may be subject to thread engagement rules that sheet metal screws (or any screws into thin metal) might not meet.
If the bond is sheet to sheet, any screws will do.
 
GoldDigger said:
If continuity is provided only by the screws then those screws may be subject to thread engagement rules that sheet metal screws (or any screws into thin metal) might not meet.
If the bond is sheet to sheet, any screws will do.
Click to expand...

What I had previously suggested was removing a screw and grinding the paint off on both sides and reinstalling it, likely with a nut so there is definite contact.

They don't look like sheet metal screws to me.
 
Looks like it’s not just a problem here in the UK.

I’ve lost count of the arguments I’ve had with contractors for not installing bonding between a removable gland plate and the cabinet. The retaining screws can’t be relied on the give continuity.
 
Simple...yes. There is no continuous bond to the cabinet....it needs a bonding jumper.

If that really is a NEMA rated enclosure, there must be a kit available.

Judging by the busy-ness in that photo, one kit isn't going to break the bank on that contract...unless this is one of multiple panels. Then, the estimator is in trouble.

Of course, whoever bought that panel with the inspection cover should have instead bought a panel where the inspection cover wouldn't have been made useless...like that one is now.
 
That is a very typical design, and I would expect that the screws that hold the cover to the main part of the equipment have been evaluated for bonding by the listing agency.
 
Ok thanks guys!!

Yes there is a gasket and yes there is an EGC in the conduit.

Yes they have a letter stating that the screws provide continuity.

This has a supply OCPD of 400 A

the way I read it all they need to do is show continuity and it is good as it is not the EGC bnut just bonding all the parts together.

The EOR has determined that a bond bushing and bond wire is required.

Thanks for all the input!!
 
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