Derating Question

[Jimmy7]

Throw away that chart and use the proper values from the NEC.

In all seriousness, can I?

 

[infinity]

In all seriousness, can I?

Did you happen to see the note that I posted from that chart in post #15? The values in this chart are no help for what you're asking. When derating a 90° C, #12 conductor you use the ampacity of the 30 amps in the NEC Article 310, T310.16.

 

[qcroanoke]

Would you leave the installation I mentioned earlier, or rip it out?

I'd leave it and sleep well tonight.

 

[Fordean]

The cable gets sleeved into the EMT and then enters into the box. I believe that a minimum of 1/4" of jacket is required in the box. Not being allowed to remove the jacket is stupid but unless the conductors are marked you're not supposed to remove it.

I

 

[Fordean]

Yes You cant strip romex U must sleeve in its entirety And have 1/4 inch viewable in box Romex has stamped/ printed info on jacket Wires inside are un rated

 

[tortuga]

Back in the old 'snake skin' days you used to see romex with "type TW" printed on the conductors.
I don't know how much the romex manufacturers are saving by not running the wire thru a printing machine but its more than $0 so they skip it, just like we skip things were not required to do, but thats all they'd need to do is just print 'THHN' on the conductors then it'd be legal.
I suspect the heat dissipation of the conduit portion is far better with the sheath stripped off.