down size wire

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Larry Everett

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We have 6-70watt MH 120 volt outside lights on 5 different 10 plex apartments. The home run was 235' so we ran 10/2 with ground romex, after the first two lights we dropped down to 12/2 with ground. The total amps on this circuit is less than 4 amps. Now we are told the wire must be the same through out the circuit. He said he was reffering to nec code 210.23. Is this correct.
 
We have 6-70watt MH 120 volt outside lights on 5 different 10 plex apartments. The home run was 235' so we ran 10/2 with ground romex, after the first two lights we dropped down to 12/2 with ground. The total amps on this circuit is less than 4 amps. Now we are told the wire must be the same through out the circuit. He said he was reffering to nec code 210.23. Is this correct.

As long as the breaker is 20 amps or less you are fine. I don't see anything in 210.23 that supports his contention.
 
I wonder if the moderator's privileges include the ability to change the date/time stamp on a post, to make it look like I posted my answer first, and that Dennis was simply agreeing with me? :wink::D
 
EC's always upsize for voltage drop. As long as the circuit is protected for the smallest conductors the circuit is safe. The only problem with upsizing is 250.122(b) or perhaps the wire being too large for the breaker. IMO, neither of these affect you anyway
 
I wonder if the moderator's privileges include the ability to change the date/time stamp on a post, to make it look like I posted my answer first, and that Dennis was simply agreeing with me? :wink::D

You have my blessings since I usually do agree with you-- except for that loft railing not being a wall. :D
 
The only problem with upsizing is 250.122(b) . . . .
There is an opportunity for controversy here, I perceive. Since the proposed installation has clearly increased the conductor size beyond that required for ampacity purposes, from a #12 (or perhaps from #14) to #10, for part of the run, do you need to upsize the EGC for the ENTIRE run, or only for the part of the run that has the #10? My view is that 250.122(B) does not contain an answer to this question.
 
Has the person who fed you this misinformation ever heard of voltage drop compensation?
 
My view is that 250.122(B) does not contain an answer to this question.

My view is your stretching very hard to find more controversy. :smile:

'Where the ungrounded conductors are increased in size'

To me that 'where' provides the answer your looking for.
 
I guess, since we are playing this game, we can site 250.122(A)
in no case shall the egc be required to be larger than the circuit conductors supplying the equipment
. I take this to mean that a #12 EGC is all that is needed on the part that is supplied with #12.
 
I also believe it's only where the circuit conductcors are larger. Besides the low-EGC-impedance reason, I can think of another: if someone ever decided to use the larger conductors nearer their rated ampacity, the existing EGC will be ready.
 
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