[Shockdoc]

I have a 2" run under the slab from one side of the home to the other to serve as a wireway for a 20kw generac and central AC compressors built on the same pedestal . As it stands 4#8s for ACs , 2#2s,1#6and a #8 and a #12 for generac. I will tap #6 generator neutral for service receptacle. Does this require derating since generator is only for emergency back up?

 

[CADPoint]

We doing homework questions now! ?

You didn't say the length... and exact pipe , PVC 40"?

Oh course you have to derate!

Oh yeah wire types...

 

[Shockdoc]

We doing homework questions now! ?

You didn't say the length... and exact pipe , PVC 40"?

Oh course you have to derate!

Oh yeah wire types...

Well 100' , type thwn but here's where it gets interesting, I am installing a relay to cut off to disengage 1st floor AC comp in the event of generator so I am limited to four current carrying conductors at all times in this conduit.

 

[CADPoint]

http://www.southwire.com/support/mobile-applications.htm

 

[Magnettica]

Just run some doorbell wire and a couple pieces of leftover scrap of the 14/3 from the last job and don't worry about it.

 

[wildleg]

if they are truly non-coincident loads (which you seem to imply), then you only need to derate according to the number of CCC that are on at the same time IMO