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Thread: Troubleshooting Heat Trace

  1. #1
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    Troubleshooting Heat Trace

    While troubleshooting a heat trace circuit, I checked continuity between the two conductors. There was continuity, but is this because of the semi conductor or is it likely that there is a short in the wiring? The circuit was not working, but the breaker did not trip as if there was a dead short in the circuit.

  2. #2
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    Quote Originally Posted by jmc24 View Post
    While troubleshooting a heat trace circuit, I checked continuity between the two conductors. There was continuity, but is this because of the semi conductor or is it likely that there is a short in the wiring? The circuit was not working, but the breaker did not trip as if there was a dead short in the circuit.
    Use an ohm meter, you need to know the resistance of the circuit. Continuity checks are just that, continuity.

    Is there power applied to the cable?
    Tom
    TBLO

  3. #3
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    Check specs

    Heat trace has a ohms per foot rating I think. .And yes self limiting does use a semi conductor.
    A cowboy may get thrown , but they always get up and walk forward.

  4. #4
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    Quote Originally Posted by ptonsparky View Post
    Use an ohm meter, you need to know the resistance of the circuit. Continuity checks are just that, continuity.

    Is there power applied to the cable?

    No, there was no power applied to the cable. Both ends of the cable were unhooked and open, so my assumption was that there should be no continuity between the 2 conductors. Is that correct?

  5. #5
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    Quote Originally Posted by jmc24 View Post
    No, there was no power applied to the cable. Both ends of the cable were unhooked and open, so my assumption was that there should be no continuity between the 2 conductors. Is that correct?
    The heat trace cable is the load. Think of it as a bunch of small heater elements, one end connected to each conductor repeat many times.
    A cowboy may get thrown , but they always get up and walk forward.

  6. #6
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    Quote Originally Posted by jmc24 View Post
    No, there was no power applied to the cable. Both ends of the cable were unhooked and open, so my assumption was that there should be no continuity between the 2 conductors. Is that correct?
    Incorrect. The heat tape is conductive throughout its entire length. The two conductors have to stay clear of each other or else you'll get a short circuit.
    Once in a while you get shown the light
    In the strangest of places if you look at it right. Robert Hunter

  7. #7
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    Quote Originally Posted by jmc24 View Post
    While troubleshooting a heat trace circuit, I checked continuity between the two conductors. There was continuity, but is this because of the semi conductor or is it likely that there is a short in the wiring? The circuit was not working, but the breaker did not trip as if there was a dead short in the circuit.
    If it uses termination boxes at the end of the run, I would just put my meter on the terminals and very I had line voltage.

    If it doesn't use termination boxes at the end, I would instead test power at the starter box and verify line voltage and then ohm the cable as Ptonsparky suggested.

  8. #8
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    Heat cable has a negative temp coefficient, the colder the temp, the lower the resistance, hence more heat.
    Check mfgs literature, get the ohms per foot/deg F
    Moderator-Washington State
    Ancora Imparo

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