# ground bushings



## looneyr6 (Nov 15, 2011)

Art.250.97 states, for circuits over 250 volts to ground, electrical continuity of metal raceways that contain any conductor other then service conductor shall be insured by 1 or more of the mthods specified for services in 250.92(b). In my case I am using 2" emt it does not have service conductors which would require ground bushing. except for the exception number 3 states fittings with shoulders that seat firmly against the box or cabinet, such as emt connectors etc. shell be permitted. my inspector called me on this. I would like some input before I take him to the book. thanks


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## RIVETER (Sep 26, 2009)

looneyr6 said:


> Art.250.97 states, for circuits over 250 volts to ground, electrical continuity of metal raceways that contain any conductor other then service conductor shall be insured by 1 or more of the mthods specified for services in 250.92(b). In my case I am using 2" emt it does not have service conductors which would require ground bushing. except for the exception number 3 states fittings with shoulders that seat firmly against the box or cabinet, such as emt connectors etc. shell be permitted. my inspector called me on this. I would like some input before I take him to the book. thanks


The NEC is supposed to be the "LAW", but when it also allows for interpretation a can of worms is opened. First off, why would there be any conductors in the raceway other than service conductors? Secondly, ANY metallic raceway must be electrically continuous from start to finish with the appropriate means, such as bonding bushings and the like that are UL approved. Maybe I am missing something.


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## HARRY304E (Sep 15, 2010)

looneyr6 said:


> Art.250.97 states, for circuits over 250 volts to ground, electrical continuity of metal raceways that contain any conductor other then service conductor shall be insured by 1 or more of the mthods specified for services in 250.92(b). In my case I am using 2" emt it does not have service conductors which would require ground bushing. except for the exception number 3 states fittings with shoulders that seat firmly against the box or cabinet, such as emt connectors etc. shell be permitted. my inspector called me on this. I would like some input before I take him to the book. thanks


Make sure your complying with the California Electrical code as well it could be something local.

Welcome to the forum...:thumbup::thumbup:


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## ralph (Apr 6, 2008)

UL approved . lock nut and plastic bushing ?


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## nitro71 (Sep 17, 2009)

Why don't you explain your install to us? Bonding bushings are a PIA to add later. If I know I'm right I'd push back hard on that one.


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## looneyr6 (Nov 15, 2011)

Maybe I wasnt clear, 400a. panel. Feeder has ground bushing as per nec. Inspector is asking for ground bushings on branch conduit.


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## looneyr6 (Nov 15, 2011)

Here's the install. 400A. 480v. panel with parallel 3/0. Both 2" feeder conduits have ground bushings per nec. Inspector is asking for ground bushings on the branch conduit which is feeding RTU's. I would just do it but some of the units are for refrigeration.


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## looneyr6 (Nov 15, 2011)

Thats what I did....He wants more????


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## Dennis Alwon (May 9, 2009)

Is the ko concentric or eccentric?


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## raider1 (Jan 22, 2007)

Did you read the Exception to 250.97?

If you don't have concentric or eccentric KO's then the exception permits standard locknuts on emt connectors to bond the raceway.

Also if you are using concentric or eccentric KOs then check the listing of the equipment you may find that they are listed for grounding and bonding above 250 volts.

Chris


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## jmsmith (Sep 10, 2011)

Dennis Alwon said:


> Is the ko concentric or eccentric?


Dennis-
Just my thot... Did the OP say whether or not it was a government job? Every one I have personally been on required grounding bushings on ALL pipe, regardless of opening type. It was speced that way, and God help if you missed one on a cable tray drop!
:blink:


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## McClary’s Electrical (Feb 21, 2009)

RIVETER said:


> The NEC is supposed to be the "LAW", but when it also allows for interpretation a can of worms is opened. First off, why would there be any conductors in the raceway other than service conductors? Secondly, ANY metallic raceway must be electrically continuous from start to finish with the appropriate means, such as bonding bushings and the like that are UL approved. Maybe I am missing something.


Sometimes I think you're smart, other times I think you're really goofy


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## looneyr6 (Nov 15, 2011)

No concentric Ko's. Not a government job. He is a city combo inspector. Sounds to me like he is wrong. Thanks for the input guys.


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## RIVETER (Sep 26, 2009)

mcclary's electrical said:


> Sometimes I think you're smart, other times I think you're really goofy


How say you...this time?


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## McClary’s Electrical (Feb 21, 2009)

RIVETER said:


> > First off, why would there be any conductors in the raceway other than service conductors?
> 
> 
> Wrong
> ...


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## knowshorts (Jan 9, 2009)

HARRY304E said:


> Make sure your complying with the California Electrical code as well it could be something local.
> 
> Welcome to the forum...:thumbup::thumbup:


There isn't much difference between the NEC and CEC as far as Articles 100-400 go, but it could be a local amendment or a spec. Not that I've ever needed it, but I keep a copy of the local code just for cases like this. At least you got a code article from the AHU, but I would have opened the book up in front of him and made sure both of you were on the same page as far as interpretation goes.


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## Carultch (May 14, 2013)

nitro71 said:


> Why don't you explain your install to us? Bonding bushings are a PIA to add later. If I know I'm right I'd push back hard on that one.


Good thing McMaster sells a good "whoops, I forgot" bonding bushing. Just remove the plastic bushing, cut it away with bolt cutters, replace with one of these, and you are good to go.


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