Twofold question here:
First, can i splice THHN copper to an existing run of aluminum SE cable in order to extend a feeder to a subpanel? I find nothing in the NEC disallowing this, as long as I use an approved copper-to-aluminum device and some No-Alox. Still, it seems weird.
Then, if i CAN do this, how would I calculate the voltage drop? would i first calculate the aluminum for just the length of the run that is a SE, and then calculate the copper for just the length that is THHN? Or would i calculate both the copper and the aluminum for the entire length of the run?
I appreciate any and all feedback. thanks.
