baseboard tripping breaker

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jemsvcs

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A four-foot electric baseboard heater wired to 240 VAC is tripping the circuit breaker after heating for approx. one half hour. Line voltage is ok, the unit is only drawing 4 amps when the heat first comes on, and there are no shorts in the circuit.

Any ideas? I'm thinking it's the thermostat, but why would the circuit breaker keep tripping?
 
Re: baseboard tripping breaker

Has it worked properly before? Has anything changed recently (e.g., new breaker, new thermostat, new heater)?
 
Re: baseboard tripping breaker

The homeowner says the unit was installed about six years ago and is rarely used. The last year or so it has been tripping the breaker after approx. one-half hour of use.
 
Re: baseboard tripping breaker

I also noticed the thermostat was possible wired incorrectly (i.e., one line (red) and one load (blk) wire of the stat were connected to the line side of the circuit...and similarly to the load). The unit still operates when over it's set point.

At least that's the way most are set up...it's a Fasco unit and they aren't manufactured any longer.
 
Re: baseboard tripping breaker

This may seem a little out there but here goes.
What is the possibility that when the heater heats up and the metals expand, a short-circuit doesn't present itself? Have you checked the wires entering the heater unit for cracks in the insulation that could be shorting to the baseboard itself when things move due to thermal expansion?

We've experienced similar situations with heaters on our machinery.

Bob
 
Re: baseboard tripping breaker

Bob,

No apparent insulation damage for the second case you mentioned. I agree it is possible for the short to occur after expansion...never thought of that.
 
Re: baseboard tripping breaker

If there's nothing else on the circuit I'd change the breaker as a test and potentialy solution.
 
Re: baseboard tripping breaker

Something is Arching somewhere.Is this a line voltage thermostat ?
 
Re: baseboard tripping breaker

Originally posted by jemsvcs:
I also noticed the thermostat was possible wired incorrectly (i.e., one line (red) and one load (blk) wire of the stat were connected to the line side of the circuit...and similarly to the load). The unit still operates when over it's set point.

At least that's the way most are set up...it's a Fasco unit and they aren't manufactured any longer.
Click to expand...
I can't remember which is which,, but the REDS are a pair(I think Load), and the BLACKS are a pair(I think Line). I could have it backwards though as some use REDS as Line and BLACKS as Load.
 
Re: baseboard tripping breaker

Just wanted to update and thank everyone for their responses.

Turns out it was the limit switch in the heating element itself. I managed to find someone who used to work for Fasco and they confirmed that the limit switches would trip the circuit breaker when they were going bad.

In fact, it appears that Fasco had alot of similar problems with other products and when they went out of business they were bought up by other companies...with the exception of their baseboard line. Go Figure.

Thanks.
 
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