Equipment GFCI for heat trace

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I have a 120V 20 Amp GFCI feeding heat trace. This is for equipment not personnel so it has a 30 milliamp trip setting. Within a few seconds after turning on the breaker...it trips. When connected to a non-GFCI it's fine and stays on. Any idea why this is happening??
 

mcclary's electrical

Senior Member
Location
VA
I have a 120V 20 Amp GFCI feeding heat trace. This is for equipment not personnel so it has a 30 milliamp trip setting. Within a few seconds after turning on the breaker...it trips. When connected to a non-GFCI it's fine and stays on. Any idea why this is happening??



welcome to the forum. Where is the heat trace? Can you visually inspect for damage? Have you tested the heat trace?
 

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
I have a 120V 20 Amp GFCI feeding heat trace. This is for equipment not personnel so it has a 30 milliamp trip setting. Within a few seconds after turning on the breaker...it trips. When connected to a non-GFCI it's fine and stays on. Any idea why this is happening??

The GFEP is probably doing it's job, Have you megged it? Though it's rarely done, most manufactures require it to be megged before and after installation. Does it have factory or field terminations?
 

mxslick

Senior Member
Location
SE Idaho
Or a bad spot or damage to the sheath of the heat trace..the slight lag before tripping tells me that as the trace warms up it faults.
 

cornbread

Senior Member
Check the length of the circuit, I've seen in the past where the cable was too long and it would trip on inrush.
 

mxslick

Senior Member
Location
SE Idaho
This is a brand new install.

Doesn't mean squat. There can still be damage to the cable or it can still have a defect.

Check the length of the circuit, I've seen in the past where the cable was too long and it would trip on inrush.

Good point.

If this install can be "divided" (couplings between cable lengths perhaps?) that would help rule out either a bad section or excess cable length.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Doesn't mean squat. There can still be damage to the cable or it can still have a defect.
...
Very true. I am aware of a case where freeze protection heat trace was installed and the piping insulated, and then they decided to steam clean the inside of the traced pipe. The steam temperature exceed the maximum permitted exposure temperature of the trace and about 10,000' feet of trace had to be replaced.
 

sgunsel

Senior Member
It is pretty easy to damage heat tracing during installation, especially at the terminations. Unfortunately, the final step (potting and sleeving) usually hides any visible damage.
 
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