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#92417 - 03/16/05 04:43 PM bond bushings
gserve Offline
Member

Registered: 03/11/03
Posts: 92
Is a bond bushing required by code to be installed on an offset nipple where one end is screwed into a myers hub mounted on the main disconnect enclosure and the other end installed into the bottom of a meter socket? These are service entrance conductors from the bottom of the meter to the top of the main disconnect(line side). Code reference please. Thanks

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#92418 - 03/16/05 04:59 PM Re: bond bushings
mustangelectric Offline
Member

Registered: 02/08/04
Posts: 496
Loc: Bentonville, AR
Hi,
Only if it is a concentric knockout..article 250 something..i will see if i can dig it up..

ok 250.92 (B)..the offset nipple is irrelevant..it doesnt matter what the raceway is ..if it is METALLIC...EXCEPT PVC of course.

That is because when the larger knockouts break the continuity is lost..

I re-read your post...you do not need a bonding bushing at the disco only the meterbase.

regards

greg



[This message has been edited by mustangelectric (edited 03-16-2005).]
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#92419 - 03/16/05 05:03 PM Re: bond bushings
Gregtaylor Offline
Member

Registered: 03/02/05
Posts: 212
Loc: Boise, Idaho, USA
Inspectors in my area do not feel that a Meyers hub meets the requirements of
250.92(B)(1) thru (4), because of the neoprene gasket, and would require a bonding bushing in the case you describe. Meyers hubs with bonding means are available.

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#92420 - 03/16/05 05:16 PM Re: bond bushings
mustangelectric Offline
Member

Registered: 02/08/04
Posts: 496
Loc: Bentonville, AR
Hi,
Myers hubs are desinged to BITE into the surface or the encloisure..the gasket is insterted in groove and does not impair the bearing of the locknut, it only keeps out water, dust etc.

As mentioned you can get myers hubs with a ground screw on the locknut..

I dont see why an inspector would not allow a meyers hub as a means of grounding!

In my opinion there is NO BETTER HUB! There are only 10 billion or more of them in use!

I have put hundreds of them in nuclear plants, refineries and oil fields with and without grounding busings...

if a 1/2 locknut is good enough there is twice the material getting a bite with a meyers hub.

Very funny though!

-regards

greg
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#92421 - 03/16/05 05:57 PM Re: bond bushings
stamcon Offline
Member

Registered: 03/24/01
Posts: 322
Loc: So San Francisco CA

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#92422 - 03/16/05 06:05 PM Re: bond bushings
gserve Offline
Member

Registered: 03/11/03
Posts: 92
If all the concentric knockouts are removed to the largest size then is it still required to have a bond bushing?

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#92423 - 03/16/05 06:07 PM Re: bond bushings
mustangelectric Offline
Member

Registered: 02/08/04
Posts: 496
Loc: Bentonville, AR
Hi,
Well what do you know!

Never heard of this before now.

I guess there will be a lot of retrofitting if there is a recall!

From now on I guess be sure to use the ones with the ground screw!

Not so funny after all!

-regards

greg
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#92424 - 03/16/05 06:09 PM Re: bond bushings
mustangelectric Offline
Member

Registered: 02/08/04
Posts: 496
Loc: Bentonville, AR
Hi,
I would say NO to that but better check it with the man..he is the one with the green sticker!

I dont see why it would be then considered concentric.

-regards

greg
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#92425 - 03/16/05 07:26 PM Re: bond bushings
caselec Offline
Member

Registered: 04/14/02
Posts: 557
Loc: San Jose, CA
I have had discussion with inspectors in my area and they feel that standard Myers hubs are acceptable. I haven’t spent much time looking through the UL directors but did look up the UL file number (E-27258) for the Basic hubs in Steve’s link. There is a note at the bottom of the UL page that says “suitable for use with service entrance conduit”.

Curt
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Curt Swartz

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#92426 - 03/17/05 12:34 AM Re: bond bushings
e57 Offline
Member

Registered: 05/27/03
Posts: 2837
Loc: S.F.,CA USA
Speaking of “suitable for use with service entrance conduit”. Is an off-set nipple “suitable for use with service entrance conduit”? NEC doesn't seem to touch on it in 230.43, but does UL list these thin die cast parts as “suitable for use with service entrance conduit”? I wouldn't use them as I don't think they have the physical strength to protect service conductors. As far as die cast parts go, a bolt on hub is made a lot stronger, like four or more times as strong as an off-set nipple. The area I work in will only accept IMC or RMC. And, I have never seen an off-set nipple used for any part of a service, other than on this forum a while back.
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