On Sun, 27 Dec 2020 09:57:54 -0500, Ralph Mowery
wrote:

In article ,
says...

The magnetic field of the hot and neutral cancel each other. Otherwise
steel conduit wouldn't be usefull.

I agree with Ralph, high current with wire wrapped can overheat the cord.
You are correct with a pure resistive load but with a capacitive or
inductive load (high power factor) if I remeber correctly there is a
reluctance issue



I doubt that the metal would be much of a factor if any. I worked in a
plant that had miles and miles of wiring in conduit. Much of it
powering large motors.

Some installer did make a major mistake on one wiring job. On a 3 phase
circuit he ran two wires in one piece of conduit that was about 5 feet
long and the third wire in another piece. Did not take long for those
wires to over heat and melt out some plastic terminal strips.

There is a big difference between one pair carrying 30 amps and 75
turns of that pair wrapped around a soft iron core carrying 30 amps
too.