Equipment GFCI for heat trace

[Michael Moran]

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]

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]

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?

 

[Michael Moran]

unfortunatley I did not do the install....just the termination

 

[cornbread]

We have a ton of heat trace here and usually we find there is a Jbox or fitting that is full of water.

 

[mxslick]

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.

 

[Michael Moran]

This is a brand new install.

 

[cornbread]

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]

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]

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]

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.