for the four dedicated 120 volt circuits I'm confused as how you only have 18 amps after deration?
110.14(C) Temperature Limitations.
The temperature rating associated
with the ampacity of a conductor shall be selected
and coordinated so as not to exceed the lowest temperature
rating of any connected termination, conductor, or device. Conductors with temperature ratings higher than specified for terminations shall be permitted to be used for ampacity
If the wire in question is THHN then you can, by virtue of the section I put up in post#2, start out at the 90 degree rating (30 amps for 12 awg).
Then referencing 310.15(B)(3)(a) you would derate to 70%. This results in 21 amps. The adjusted current does not exceed the temperature rating of your terminations so a 20 amp OCPD could still be utilized.
Or, as you said, you could use 15 amp OCPD's. You have a choice.
FWIW... the ultimate outcome, using your logic, would still be code compliant but it would typically result in larger wire which equals additional cost.
I wasn't trying to say you did anything wrong. I was just showing the allowances in the NEC.
I hear ya, I moved recently and not sure where my 05 book is at, going by what my app (elec pro) shows.
I don't do much conduit work so some things are a little fuzzy.
Everything on the 50 amp circuits look alright then? I don't have a 1" bender so I'm going to fudge some premade and get it close. According to the calcs I have to upsize to #6 and I can't put 4 of those in 3/4 (with a #10 ground) otherwise I'd run two 3/4" with #8 but it derates to 42a with 4 conductors.
Everything on the 50 amp circuits look alright then? I don't have a 1" bender so I'm going to fudge some premade and get it close. According to the calcs I have to upsize to #6 and I can't put 4 of those in 3/4 (with a #10 ground) otherwise I'd run two 3/4" with #8 but it derates to 42a with 4 conductors.
Can't really say... what are the "50 amp" loads? If you are talking about a 440 or 430 application your MOCP may be larger than the wire you actually need.
Also, you can put four - 6 awg conductors in the 3/4 conduit (assuming EMT) and use the conduit as the EGC.
Lol, yeah, I know, most of my stuff is lv so I get away with smurf tube. With this cat6 though it's thicker and 3/4" doesn't always cut it anymore.
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