heat trace cable..... a question....

[kwired]

Based on a fixed resistance:
Double the voltage is double the current.
Double the current is four times the power.
Therefore double the voltage is also four times the power.

There I went again, saying things that I do know but somehow don't get it right.

Correct it is power that is four times not the current.

 

[weressl]

No but you said
My point was doubling the voltage raises the temp. so it is a problem for the insulation breakdown. NO?

Original point I was responding to: " it will have to be able to withstand the higher voltage or it will break down." The insulation is able to withstand the higher voltage. The failure will not be instantaneous and will be direct result of the additional heat produced.

 

[Fulthrotl]

ok... after four days of bringing the run up to temperature, the
24 amp draw is fluctuating between 9~10 amps...... stuff
meggers ok, everything seems ok, and the self regulation is
evident.... and some of the process piping went down and back
up, so that 100' +- moved up to close to 200'.

the variance i got was more than a 60% current increase between
ambient and 110 degrees F that some of the reading i was doing
led me to believe.

an interesting pamphlet on the stuff..... well, maybe not interesting,
but helpful....

http://www.appliedproducts.com/_asset/2jxg12/SelfReg-PwrLimit_IOM.pdf