Just another upsized ground question

[ggonza]

Okay so in 250.122(B) it states" Where ungrounded conductors are increased in size, equipment grounding conductors, where installed, shall be increased in size proportionately according to the circular mil area of the ungrounded conductors".
So the argument that some of my co-workers and I had was this. They felt that the rule only applies when you intentionally upsize the ungrounded conductors. For example: voltage drop, or engineer spec. But I felt that it would apply no matter what. For example: you need to pull a 20 Amp circuit, it calls for # 12 Awg . And all you have left is #10 Awg. But you still had enough #12 to pull for the egc. (this was the actual setup that was being pulled in for most of the branch circuits). I feel like you would need to pull a #10 egc with #10 ungrounded conductors, even though it's a 20 A circuit. what do y'all think?

 

[bob]

The NEC says that you upsize the EGC when the phase conductors are increased for VD. Read this post.

http://forums.mikeholt.com/showthread.php?t=117577

Please give me your comments.

Thanks

 

[infinity]

If the ungrounded circuit conductors are upsized for any reason, including you only had larger wire on the truck, then 250.122(B) applies and the EGC must be upsized as well. You'll notice that this only applies when the ungrounded circuit conductors are increased in size. If you only had an over sized neutral then it wouldn't apply.

 

[chris kennedy]

The NEC says that you upsize the EGC when the phase conductors are increased for VD.

Troublemaker.:roll:

Read this post.

http://forums.mikeholt.com/showthread.php?t=117577

Please give me your comments.

Thanks

Is there a specific post in there to prove your point? I just read all 71 of them and now I don't have time to make my lunch.

OP, the current wording of 250.122(B) would force an install described in Rob's post above.

 

[ggonza]

Yes thank you, I do agree with Rob. The reason I couldn't persuade my co-workers, is because it doesn't exactly say " for any reason" in there. I just wanted to see what you guys thought in case I was missing something. Thank you.

 

[iwire]

Yes thank you, I do agree with Rob. The reason I couldn't persuade my co-workers, is because it doesn't exactly say " for any reason" in there. I just wanted to see what you guys thought in case I was missing something. Thank you.

If you go back a few code cycles you will see that it used to say 'for voltage drop' but then that was removed.

 

[M. D.]

If the ungrounded circuit conductors are upsized for any reason, including you only had larger wire on the truck, then 250.122(B) applies and the EGC must be upsized as well. You'll notice that this only applies when the ungrounded circuit conductors are increased in size. If you only had an over sized neutral then it wouldn't apply.

I dislike the language because it does not state a starting point ..

If it is the only wire on the truck then it has not been up sized ,. if the truck is the starting point . They should have said from the minimum size allowed by the applicable code articles.

 

[bob]

Troublemaker.:roll:

Is there a specific post in there to prove your point? I just read all 71 of them and now I don't have time to make my lunch.

OP, the current wording of 250.122(B) would force an install described in Rob's post above.

No. This subject was discussed in detail. I thought the question that the OP asked was covered. This is a dumb rule and is not based on any science. I would hope the rule would be removed in the new version of the NEC.

 

[charlie b]

This is a dumb rule and is not based on any science. I would hope the rule would be removed in the new version of the NEC.

It won't. Not in the 2011 at least. I tried. Actually, what I tried to get them to do was to clarify the starting point. I was later told by a member of the CMP, one who was involved with the discussions, that my proposal cost them quite a long time to debate, and they never came to a conclusion. The problem seemed to be finding words that make the intent clear.

 

[bob]

I thought an improvement would be to use table 250.122 as the minimum size EGC. If the engineer wanted to increase the circuit size then an increase in the EGC would not be required unless the calculations showed it to be necessary. Easy for the inspector to check.