Bonding that ole ground rod conduit

[lile001]

I understand that when you run a wire to a ground rod, or some other ground connection such as structural steel, that it is best to protect the wire in a conduit. Also, it is best to bond both ends of that conduit if it is metal.

Typically, I might be using this with a 3/0 bare copper wire in a commercial building, bonding some structural steel or rebar.

I have thumbed through an OZ Gedney and an Appleton catalog, but have yet to find a fitting that will accomplish bonding the end of an EMT conduit to a bare 3/0 ground wire coming out of it. Any suggestions as to the name of this gizmo and who makes one?

 

[sandsnow]

Re: Bonding that ole ground rod conduit

Go to T & B Blackburn . Page F114 should be what you are looking for. Screws onto EMT connector.

 

[macmikeman]

Re: Bonding that ole ground rod conduit

Mr. Levoir, Since they make a listed connector like the exact ones you pointed out for this use, would that make the practice of using a grounding bushing screwed onto the emt connector an incorrect practice?. I just did one like that and have not called inspection on it yet, and am now wondering if I need to change it to the specific one shown on that page you reference.

 

[sandsnow]

Re: Bonding that ole ground rod conduit

Originally posted by macmikeman:
Mr. Levoir, Since they make a listed connector like the exact ones you pointed out for this use, would that make the practice of using a grounding bushing screwed onto the emt connector an incorrect practice?. I just did one like that and have not called inspection on it yet, and am now wondering if I need to change it to the specific one shown on that page you reference.

As long as the lay in lug on the ground bushing is the one that came with it, correct size for the conductor; you should be good to go.
The mistake I see some make is using a #6 wire from the bushing when there is a 3/0 inside the conduit.
Mister is too formal, first names are better

 

[infinity]

Re: Bonding that ole ground rod conduit

The mistake I see some make is using a #6 wire from the bushing when there is a 3/0 inside the conduit.

I see this all of the time. A 3/0 or larger conductor in a metal conduit with a #10 or #8 tail from the bonding bushing to a grounding buss.

 

[macmikeman]

Re: Bonding that ole ground rod conduit

Thanks Larry, when you are an inspector it is my "learned this from my mom habit" to address by the title Mr. until invited to use your first name.

 

[lile001]

Re: Bonding that ole ground rod conduit

Originally posted by infinity:

The mistake I see some make is using a #6 wire from the bushing when there is a 3/0 inside the conduit.

I see this all of the time. A 3/0 or larger conductor in a metal conduit with a #10 or #8 tail from the bonding bushing to a grounding buss.

I am trying to understand what the issue would be with this pigtail arrangement. What if the pigtail was short, and bonded right to the 3/0 wire with a tap connector? It seems like this would accomplish the purpose. Any thoughts?

 

[lile001]

Re: Bonding that ole ground rod conduit

Originally posted by sandsnow:
Go to T & B Blackburn . Page F114 should be what you are looking for. Screws onto EMT connector.

Thanks for the reference! Just what I was looking for!

 

[sandsnow]

Re: Bonding that ole ground rod conduit

Originally posted by lile001:
I am trying to understand what the issue would be with this pigtail arrangement. What if the pigtail was short, and bonded right to the 3/0 wire with a tap connector? It seems like this would accomplish the purpose. Any thoughts?

The code requires the conduit to be bonded to the conductor. The 'pigtail" in this case has to be the same size as the conductor inside. Sorry no code reference. I am short on time here.

 

[augie47]

Re: Bonding that ole ground rod conduit

250.64 (E) "the bonding jumper ...shall be the same size as,or larger than, the required enclosed grounding electrode conductor". no allowance for reducing the "pigtail"

 

[lile001]

Re: Bonding that ole ground rod conduit

Originally posted by augie47:
250.64 (E) "the bonding jumper ...shall be the same size as,or larger than, the required enclosed grounding electrode conductor". no allowance for reducing the "pigtail"

Thanks, Augie, you nailed it!

 

[eprice]

Re: Bonding that ole ground rod conduit

Originally posted by augie47:
250.64 (E) "the bonding jumper ...shall be the same size as,or larger than, the required enclosed grounding electrode conductor". no allowance for reducing the "pigtail"

That is an addition to the 2005 NEC. Prior to the 2005, I can't find a specific requirement for the size of these bonding jumpers, but other bonding jumpers associated with the grounding electrode system and/or on the supply side of the service are required to be sized by section 250.66 in sections 250.53(C) and 250.102(C).