I am installing electric floor heat in my bathroom. It will be on a dedicated 120V/20amp circuit. The breaker has a GFCI. I am using same manufacturer for thermostat as floor heat. The thermostat is a 120 Volt stat that is connected to the line and load. . The thermostat includes a integral GFCI. The thermostat's GFCI has a end-of-life feature to isolate the heating cable load. Question: Should I keep the system with 2 GFCI's or should I replace the breaker GFCI with a regular breaker? I can't disable the thermostats GFCI.

  • Basic answer is just use one gfci. But hang on a bit and Harper will add his tripping picture. Commented Nov 1, 2020 at 22:16
  • 2
    What do the manufacturer’s instructions say?
    – nobody
    Commented Nov 1, 2020 at 23:42
  • Note that you may need an AFCI breaker for this, depending on what NEC edition your AHJ uses Commented Nov 2, 2020 at 0:03
  • 1
    mana' is referring to this :) which might also answer your question. Commented Nov 2, 2020 at 1:43

1 Answer 1


I would not put a GFCI breaker on this device. Code requires it to be GFCI protected and 2 GFCI devices can cause trouble in resetting.

I ran into a issue with one of the floor style that ran a self test that would trip the breaker so we could never reset it (the home owner called me I megged the heater and it was good so then I pulled 1 lead to the heater still tripped the panel breaker, called the mfg and they told me it was in there GFCI test that was tripping the circuit. I believe this test was the end of life test where it basically megged the circuit prior to energizing looking for leakage that may not show up on a standard test until wet.

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