Dearate conductor..EGC also?

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Twoskinsoneman

Twoskinsoneman

Senior Member
Location
West Virginia, USA NEC: 2020
Occupation
Facility Senior Electrician
Got a situation where have to use 12awg single conductors in EMT for 15 amp circuit because of derate due to more the three current carrying conductors. I don't have to pull 12awg EGS do I? I can still pull 14awg right?
 
How many CCC's do you have in the raceway? You need to have more than 9 for derating to have an impact on using a larger conductor.
 
infinity said:
How many CCC's do you have in the raceway? You need to have more than 9 for derating to have an impact on using a larger conductor.
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yeah..got 12 conductors have to derate 50%

To be honest I am taking this job over and am a little baffled at what was done. I've got 4 circuits in EMT. He ran 14awg EGCs for each circuit 12awg for the grounded and ungrounded conductors...
 
You have 12 conductors for 4 circuits? Are these 120 volt circuits? 4-hots, 4-grounded conductors and 4-egc?s? If so then you only have 8 current carrying conductors not 12.
 
Twoskinsoneman said:
yeah..got 12 conductors have to derate 50%

To be honest I am taking this job over and am a little baffled at what was done. I've got 4 circuits in EMT. He ran 14awg EGCs for each circuit 12awg for the grounded and ungrounded conductors...
Click to expand...

Perhaps I'm mistaken...this sounds like you only have 8 current carrying conductors [? 4 ckts of line & ground + 4 EGC for your 12 conductors?]....if this is in fact the case you do not have to derate 50%....only 70%....derating applies to current carrying conductors only.
 
yeah sorry about that. There is a fith circuit (I keep forgetting it because it isn't labelled) The entire contents of the single conduit is 5 circuits each with individual EGCs (2 12awg and 1 14awg) and there is also a circuit for low voltage lights in the same conduit! So I've got 10 ccc for the 5 circuits and 2 ccc for the low voltage lighting.
 
infinity said:
I guess in my head that was implied since he mentioned #14 and #12 conductors in the OP.
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No problem. I was just clarifying that the 9-conductor 'short-cut' only applies to 12 and 14.
 
Twoskinsoneman said:
yeah sorry about that. There is a fith circuit (I keep forgetting it because it isn't labelled) The entire contents of the single conduit is 5 circuits each with individual EGCs (2 12awg and 1 14awg) and there is also a circuit for low voltage lights in the same conduit! So I've got 10 ccc for the 5 circuits and 2 ccc for the low voltage lighting.
Click to expand...
If individual branch circuits are not spec'd, consider making some mwbc's and capping off the unused whites... i.e. reduce the number of ccc's.

Any way you go about it, though, the #14 egc's need reworked in some manner, if the circuits are to remain at 20A. Right now what's going through my mind is... Is there a code prohibiting the paralleling of egc conductors? I know there is for ungrounded and grounded, but what about groundING conductors? Tie 'em all together perhaps :), but probably doesn't solve the problem downstream where they split out of the home run as singles :-(
 
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