EMT as Ground

[scubadu1]

Trying to find where I can read about using the EMT as the ground. Artical 250.118(4) says you can, but is that for equipment grounding only? I was going to use the EMT as ground with bond bushings. Local inspector said I have to have a seperate ground wire in all my conduits. I went ahead and put ground wires in all conduits including the 2" sub panel feed. Just looking for some clarity for future. This is not any kind of health care facility.

 

[Dennis Alwon]

Art. 358.60

 

[scubadu1]

Thank you for the reply. Does that also cover my service sub feed conduit?

 

[roger]

but is that for equipment grounding only?

Yes that is what 250.118 is saying, it can be used for an EGC

I was going to use the EMT as ground with bond bushings. Local inspector said I have to have a seperate ground wire in all my conduits.

The inspector is wrong if he/she is saying this is an NEC requirement, if there is local rule he/she may be correct.

Roger

 

[scubadu1]

Thanx again. I thought I knew what I was talking about, but questioned my thinking when the Inspector said what he said. Our local jurisdiction does not have any clue about this. He said he has never seen a electrical system ever done like that. Thank you for the clarification for my own piece of mind.

 

[suemarkp]

I think the separate wire is "better", because if one of your EMT couplings comes apart then you've lost your fault path. But code doesn't require "better', only "minimum". I'm not sure how often screw type or compression couplers come apart. If things are well secured, it should be pretty robust even with all the screws loose.

 

[kwired]

Our local jurisdiction does not have any clue about this. He said he has never seen a electrical system ever done like that.

This inspector has not been inspecting or been in the trade very long, this has been a common practice for probably as long as metal raceways existed. The ones that you see that do come apart and interrupt continuity were usually poorly installed in the first place.

Bonding bushings may be required where there is concentric or eccentric knockouts or other reasons where continuity is questionable at times, but this is to ensure a good bond to the raceway which can still be used without a separate equipment grounding conductor within the raceway.