250.122c and inspector question

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kbrandt

Member
Location
arizona
Trying to get this clear in my head. I know that 250.122c says you can run one eq. ground for multiple circuits in the same conduit as long as it is sized for the largest overcurrent device, my question is:

Question 1--Is there a limit to the number of circuits, as I'am putting in a new service at a home and I have to move it to the end of the house.So I have 7-20 amp sp 120 volt circuits and 2- 30 amp 2 pole circuits is it o.k. to run just one #10 for the eq. ground? And just tie them all together under one split bolt or ground bar at the junction box that is located where the old service was?
I read it as yes,but need some backup to make sure this is right.

Question 2-- I have an inspector who does not know the code well and he always falls back on ("Well we like to see it that way") When I know that it is legal. Should he have to show me it in writing or should I just not bother and do what he says, sometimes I end up making another trip because of him. By the way he is my neighbor and we've know each other for 15 years before he was an inspector and I was a contractor. This ties into 250.122c because I know he will question me on this eq. ground for the service change.

Thank you in advance for any input.
 

gndrod

Senior Member
Location
Ca and Wa
kbrandt said:
Trying to get this clear in my head. I know that 250.122c says you can run one eq. ground for multiple circuits in the same conduit as long as it is sized for the largest overcurrent device, my question is:

Question 1--Is there a limit to the number of circuits, as I'am putting in a new service at a home and I have to move it to the end of the house.So I have 7-20 amp sp 120 volt circuits and 2- 30 amp 2 pole circuits is it o.k. to run just one #10 for the eq. ground? And just tie them all together under one split bolt or ground bar at the junction box that is located where the old service was?
I read it as yes,but need some backup to make sure this is right.

Question 2-- I have an inspector who does not know the code well and he always falls back on ("Well we like to see it that way") When I know that it is legal. Should he have to show me it in writing or should I just not bother and do what he says, sometimes I end up making another trip because of him. By the way he is my neighbor and we've know each other for 15 years before he was an inspector and I was a contractor. This ties into 250.122c because I know he will question me on this eq. ground for the service change.

Thank you in advance for any input.

Hi kbrandt,

Not quite clear on what kind of J-box or is it truely a sub-panel? Is this an adobe brick type structure that will require conduit? Sounds like running a feeder with SER would be a better alternate if stick frame structure. Just curious. rbj
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
"common" equipment ground

"common" equipment ground

The method you describe is very common here.
IMHO a ground bar would be best as a split bolt is not rated for multiple conductors (there were earlier threads on this subject)

As far as question #2, I suggest you review the code and, if questioned, show him the allowance. Hopefully you won't have to take it any further.
 

kbrandt

Member
Location
arizona
grndrod

grndrod

grndrod,
This is a brick house and it is not a sub panel.
Moving new service to end of house and running emt to nema 3 j-box (which will be at old service location) to tie in circuits to new service.

It has to be moved, it is to close to the gas meter,built in the 50's poco will not allow anymore.

Thanks guys
 
augie47 said:
The method you describe is very common here.
IMHO a ground bar would be best as a split bolt is not rated for multiple conductors (there were earlier threads on this subject)

As far as question #2, I suggest you review the code and, if questioned, show him the allowance. Hopefully you won't have to take it any further.


Augie is "spot-on". Follow his advice and just keep your code book handy for the inspection.
I love it when the guys are on the job, ready for me with markers in their book to explain to me what and why they have done the job. :grin:
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
mistermudd said:
Sounds okay to me, I count more than 10 CCC so you need to derate per table 310(B)(2)(a) & upsize the EGC to comply with 250.122(B).


I think that you meant 310.15(B)(2)(a).


As others have said, forget the split bolt due to it not being listed for 10 conductors. And as mistermudd said you will need to consider derating since you'll have at least 12 CCC's within the conduit.
 
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