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#100296 - 11/09/06 07:01 PM 250.96 (A)  
ShockMe77  Offline
Joined: Jun 2005
Posts: 821
Rahway, New Jersey
Would any of you consider using a chase nipple as a primary means to bonding a threaded 1-1/4" LB if the chase nipple was attached to an enclosure through an eccentric knockout?

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#100297 - 11/10/06 07:45 PM Re: 250.96 (A)  
ShockMe77  Offline
Joined: Jun 2005
Posts: 821
Rahway, New Jersey
So the chase nipple is going though an eccentric knockout in a panel and attached to a threaded LB. In your opinion, does this wiring method meet NEC requirements?



#100298 - 11/10/06 07:58 PM Re: 250.96 (A)  
George Little  Offline
Joined: Jan 2004
Posts: 1,489
Michigan USA
Ron if this is a circuit over 250v. to ground then it might be a violation. 250.97 If this is a Service raceway and this is the method of bonding then it might be a violation. 250.92 Your not giving us much information. I don't think it's a good installations but I've seen it done and can't really argue that it's not "effectively bonded" based on my understanding of the term. In technical terms it's "pig work". You only have to bond one end of a raceway sometimes, even on Service raceways. Now what brings up this question?

George Little

#100299 - 11/10/06 08:27 PM Re: 250.96 (A)  
ShockMe77  Offline
Joined: Jun 2005
Posts: 821
Rahway, New Jersey
Thanks George. I bring this up because I was on a job where this was done and I was concerned that the pipe was not properly bonded. IMO it's not. The guy who did it is one of these guys that can do no wrong no matter what you tell him and I've just given up trying. In my opinion it's a poor bond. I'm very concerned about the installation because the pipe feeds numerous pieces of commerical kitchen equipment (28 current-carrying conductors in all) and I'd hate to to later find out that someone died there because a ground fault did not clear when it should have. And because this job had no permits, there is no paper trail, and therefore no responsibility if a fatality occurs.

#100300 - 11/10/06 09:01 PM Re: 250.96 (A)  
iwire  Offline
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
Shock it may be a violation if over 250 volt but I have very little doubt it is bonded well enough if you have 28 current carrying conductors.

When you have multiple conductors you base the grounding on the single largest OCPD protecting the circuits. Not the collective total.

So what would that be.....a 20 amp breaker vs a 1 1/4" LB and chase?

One last thing is that if the fittings don't bit into the paint the paint should be removed.

Bob Badger
Construction & Maintenance Electrician

#100301 - 11/11/06 02:04 PM Re: 250.96 (A)  
HotLine1  Offline

Joined: Apr 2002
Posts: 6,811
Brick, NJ USA
OK, now let's dig a little deeper.....
1-1/4" raceway.....comm kitchen equip....28 current carrying conductors.....

45% derated, for 28ccc; ambient in comm kitchen?? site discussion for sure, or plan review reject/clarification........OH, I FORGOT, no permit, no inspection....

No paper trail??? DO NOT BET your life, or $1; you may be surprized how quick the client 'fesses' up who did the work. It's not really that hard for an AHJ, cop, insurance adjuster, etc., to get info.

That said, the chase nip debate cannot get a firm answer from me. More info needed.



#100302 - 11/12/06 10:55 AM Re: 250.96 (A)  
luckyshadow  Offline
Joined: Jan 2005
Posts: 305
Maryland USA
NEVER assume there's no paper trail.
Just wait till something goes wrong and see how fast the owner comes up with the cancelled check that the contractor deposited into his business account. Not to mention anything the contractor wrote down on company letterhead. Put somebody in a hot enough seat and they come up with all kinds of interesting paperwork in order to save their own butt.
You failed to mention whether a full size grounding conductor was installed in the conduit in question.

#100303 - 11/12/06 12:04 PM Re: 250.96 (A)  
earlydean  Offline
Joined: Dec 2003
Posts: 751
Griswold, CT, USA
Chase nipples cannot provide proper bonding, as there is no way to "bite" into the enclosure (same reason why reducing washers cannot provide a bond). The threaded connection into the LB would be sufficient (if wrenchtight) for bonding the locknut to the LB, but not to bond the nipple or the LB to the enclosure. Locknuts do "bite". Sounds like either a green wire EGC bond would be required in this installation or replace the chase nipple with a close nipple and use two locknuts (and maybe a bushing).

BTW removing paint may lead to rust problems in the future. Always repaint over the bonded connection after it's all terminated and tightened.


#100304 - 11/12/06 12:26 PM Re: 250.96 (A)  
George Little  Offline
Joined: Jan 2004
Posts: 1,489
Michigan USA
Earlydean- While I support you professionalism and if I were installing the job I would not use chase nipples as this thread discribed them being used nor would I use reducing washers except where I had to for some unknown reason. While there are code reasons to not use these items for Service raceway bonding or over 250v. to ground, etc. the use of reducing washers and chase nipples is a code compliant installation and as an inspector we usually accept them when installed correctly.

George Little

#100305 - 11/12/06 12:58 PM Re: 250.96 (A)  
Roger  Offline
Joined: May 2002
Posts: 1,716
Unfortunatly, reducing washers are suitable for grounding per UL. (not that I agree they should be)

From the White Book:

[Outlet Boxes and Fittings Outlet Bushings and Fittings

Guide Information

Metal reducing washers are considered suitable for grounding for use in circuits over and under 250 V and where installed in accordance with ANSI/NFPA 70, "National Electrical Code."


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