derating conductors

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warriorelectrician

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Anacortes Washington
I am doing a job that I am going to add 12 20 amp circuits, 1 40 amp, and 1 30 amp circuit It all needs to be ran in conduit. I am going to run thhn in the conduit and I'm not sure the best way to do this. I tried talking the homeowner into a sub-panel to make it easier but it is for an addition and he does not want to see the panel. I am thinking I need to run multiple conduits but not sure the best way. Also I was told I only need to run one ground per conduit???
 
Taking derating into account, you probably want to use multiple conduits.
With the new requirements for simultaneous disconnect on multiwire branch circuits (210.4) many folks prefer separate neutrals so that will add to your derating situation in such a manner that you probably would want only four circuits (each with a grounded conductor) per pipe.
Only one EGC need be installed per conduit (with metallic conduit 0 may be required)
 
I guess not!!

I based my question on this question:
Also I was told I only need to run one ground per conduit???
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I guess I can't get over being told to get lost (Go else where to ask simple questions--that may be DIY work) when I asked a question about grounding about 6 years ago. :D


Any way, I agree with augie.
 
warriorelectrician said:
As far as the one grounding conductor if I had 4 20amp circuits in a pipe I would only need one #12 ground.
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I once had an inspector tell me if I had more than once conductor on one phase I would need to add an EGC for each conductor on the same phase. It did not impact my work or the inspection that was being performed (it just came up in conversation) so I just let it pass.
 
hardworkingstiff said:
I once had an inspector tell me if I had more than once conductor on one phase I would need to add an EGC for each conductor on the same phase. It did not impact my work or the inspection that was being performed (it just came up in conversation) so I just let it pass.
Click to expand...

Sounds like he needs a code refresher course.
 
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