self regulating heat trace circuit

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wmthompson90

Member
Location
ky
Occupation
electrician
How are you determining the length of self regulating heat trace you can have on a circuit? learned the hard way you can not use the watts per foot to determine ampacity.
 
200’ of 120v 8 watt self regulating heat trace will not hold on. 20 amp circuit when ambient temperature drops to a certain level. Ohms law will tell us it should only draw 13 amps. With self regulating cable and pipe not yet insulated it starts off at around 70 amps and slowly drops before tripping
 
I believe the watts per foot rating is at some reference temperature. If the temp drops below that, it will be more. Do you have the detailed specs?
 
wmthompson90 said:
200’ of 120v 8 watt self regulating heat trace will not hold on. 20 amp circuit when ambient temperature drops to a certain level. Ohms law will tell us it should only draw 13 amps. With self regulating cable and pipe not yet insulated it starts off at around 70 amps and slowly drops before tripping
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It is doing what it should do. Installation instructions list the length and breaker size recommended. The one brand I looked at shows 180' on a 20 amp. Of course, YMMV.
 
ptonsparky said:
It is doing what it should do. Installation instructions list the length and breaker size recommended. The one brand I looked at shows 180' on a 20 amp. Of course, YMMV
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did not come with instructions but a quick search on there website with mode number found it. thanks.
 
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