ECN Forum Forums General Topics of the Trade General Discussion Area Derating wire plus voltage drop

If you already upsized the wire for voltage drop would you have to further derate the wire if you have more than 4 current carrying conductors? Do the calculations compound?

Here's something that might help you:
https://www.electrical-contractor.net/ubb/Forum1/HTML/001967.html

First caculate the load.
Size the wire for the load.
Derate per the table 80%. This will give you a larger conductor. Caculate the VD using this conductor.
If you have to go larger you do not derate again.