Bond Bushing requirements help

[Strombea]

I have a greenhouse where I will be putting a gutter in between the 480v panel and the grow control Panel. I usually would do this using a 3" rigid coupler and 2 chase nipples. So No way to put a bond bushing on it. I will be using my own KOs so no concentric. From what I see in 250.97, I can do this as the chase nipple will seat flush to the Panel can (No Paint).

Also im confused if you ever need bond bushings if I run a Bond jumper from the 480v panels ground bar to the grow panel ground lug. I would also think that length would play a role, less than 24"? A chase nipple is only like a 4" raceway.

I have to do it in 12 greenhouses so I want to get it right.

Thanks for any help!

 

[tank728]

Many have a concern that the chase nipple was made with straight threads and the threaded coupling was designed (and listed) to have taper threads installed into it via conduit. This creates a violation. Others feel as long as the chase nipple assembly is wrench tight you are good to go.

Personally I feel the latter. I understand the appeal of using a chase nipple from a wiring stand point, it's very flush to the cabinet you are entering. But seeing that you have concerns, maybe consider using a close nipple and 4 lock nuts

 

[Fred B]

Issue 1 to consider. Is the chase nipple "listed" for use in combination with the rigid nipple? If not that would be a violation.
Issue 2 is chase nipple listed to serve as a mechanical grounding bond? If not might be a violation.
If you can meet #1 you might consider a bonding wedge like this:

T&B 3657 3IN WEDGE | Gordon Electric Supply, Inc.

T&B 3657 3" GROUNDING WEDGE

www.gordonelectricsupply.com

 

[Fred B]

Just a side note as to use of field made combinations.
Was just at a codes training that had a Rep from UL as a presenter that addressed mixing usage of various connectors. He stated listings come about by testing various connectors in combination and exposing them to various extremes. If they pass the tests, the combination become "listed to use together. Majority of the "field made" combinations are not a listed combination and are a violation of the "listing" and be extension a violation of code. He showed many examples of such violations, some of which have been suggested and virulently defended here on this forum. But ARE a violation of code as stated by the UL rep who is also called on as an expert witness in court cases involving electrical installation safety.

OP suggestion that he wants to use a rigid Chase nipple to rigid coupling appears would be a listed combination. And use of the Bonding wedge is listed to be used with the rigid conduit fittings.

 

[infinity]

IMO the two chase nipple and coupling routine is not code compliant (I do see this all of the time). Just use a rigid nipples instead. If there are no concentric or eccentric KO's a bonding bushing is not required.

 

[Fred B]

IMO the two chase nipple and coupling routine is not code compliant (I do see this all of the time). Just use a rigid nipples instead. If there are no concentric or eccentric KO's a bonding bushing is not required.

You have a code reference that prohibits? Please.

 

[infinity]

You have a code reference that prohibits? Please.

UlL has decided that this is an issue.

Fittings into Hubs

Recently, i witnessed an electrical inspector and a group of electricians discussing the effectiveness of the bonding and grounding path where raceway fittings are used to connect raceways to threaded hubs, threaded bosses or conduit bodies. Although this is a fairly common practice in the...

www.ecmag.com

 

[Strombea]

Thank you guys for all the info it does suck that the rigid Chase nipples aren't listed to be used like that yet hopefully someday they will be because it makes it much easier IMO.