mixing wire types in conduit

[chrisd]

I was under the understanding that a 75 degree wire in a conduit would force you to derate the 90 degree wires in the same conduit. Fair enough, but an inspector uttered to me that mixing wire types is just not allowed at all. Is this true? If so where is it written?

[bigrockk]

Hmmm Looks to me like Rule 4-004(4)(11) would contradict that inspector:

4-004(4)(11) States:
The ampacity of conductors of different temperature ratings installed in the same raceway shall be determined on the basis of the conductor having the lowest temperature rating.

The only rule I could find close to what he indicated refers to single conductor cables but I don't believe this applies.

Rule 12-106(3)States:
Where single-conductor cables are used, all single-conductor cables of a circuit shall be of the same type and temperature rating and, if run in parallel, shall be in accordance with Rule 12-108.