While it might appear that derating is required, I don't think so.
There are other wire combinations that after derating produce more heat than this wire combination before derating.
The total breaker amperage at 220v of these wires appears to be over 200amps. So the current is limited by the mains not by the actual breakers.
Load diversity/actual usage would place the actual heat production at a fraction of what is allowed.
Too much attention is paid to derating in a residence.
[This message has been edited by George (edited 06-02-2004).]
