# of times required to derate wires

[bradb]

I have an application where I want to run multiple circuits from an electrical panel. Panel is a 1ph 120/240v residential type. I have a 2" pvc conduit from panel to new garage requiring the following circuits. 10-20amp 1p(#12 thhn cu), 2-30amp 2p (#10 thhn cu), 2-40amp 2p (#8 thhn cu) Distance is approx. 50lf. Can all this wiring be put in this conduit....or not?

 

[wirenut1980]

Re: # of times required to derate wires

Think subpanel...I believe an electrician would be able to help you with an estimate/method.

 

[suemarkp]

Re: # of times required to derate wires

Yes you could put all those wires in a conduit, but you'll be derating heavily and will need to up the wire one or two sizes.

If this garage is a detached building from the supplying panel, then you must use a feeder. For this application, I think a feeder and subpanel may be a better solution. Or, run multiple smaller conduits so you can cut the conductor count to about 8 or 9 per conduit.

 

[celtic]

Re: # of times required to derate wires

Originally posted by bradb:


10-20amp 1p(#12 thhn cu),
2-30amp 2p (#10 thhn cu),
2-40amp 2p (#8 thhn cu)

18 CC conductors(minimum count)@ 50% capacity (Table 310.15(B)(2)(a))....

Can all this wiring be put in this conduit....or not?

Who cares if it will fit, the wires appear to be grossly undersized.

 

[infinity]

Re: # of times required to derate wires

Can all this wiring be put in this conduit....or not?

The answer is no. As mentioned above this would require derating and using larger conductors. A subpanel should be installed to simplify your installation.

 

[pierre]

Re: # of times required to derate wires

"Can all this wiring be put in this conduit....or not?"

They will physically fit in the conduit as per code, but as been mentioned there is an ampacity adjustment that will most likely require changing the size of the conductors.