I was wondering about the correct way to wire a 240V sauna heater/thermostat in a sauna I have built.

From the heater I have a black, white, and bare wire. The black and white connect to separate terminals on the thermostat switch, the bare goes to the ground nut.

Under the house is a 120V/240V GFCI. From that I have a Black(hot), Red(hot), White(neutral), and bare wire. I figured I will connect one of each hot wires to the heater's black/white wires via the thermostat switch. The bare wire will go to the ground nut. I was wondering what happens with the white wire in this case?

I've read it is bad practice to tie the neutral to the ground so what do I do with it?

1 Answer 1


If your sauna heater is a 240 volt heater, you don't need the grounded (neutral) conductor. You can simply cap it off using a twist-on wire connector, or other approved means.

  • Ok I guessed this was the solution. Can I add onto my question then, I also want to pull 120V from one of the legs to power a lamp in the sauna. Can I just wire the lamp between one of the hot legs and neutral? And I'm assuming my GFCI is configured for 120V and 240V loads, if not I'll cross that bridge later
    – JoshNZ
    May 12, 2015 at 1:32
  • Yes, if you also need to power 120 volt loads, you can connect them between one of the ungrounded (hot) conductors and the grounded (neutral) conductor. Just keep in mind though, you'll have to use conductors that are sized appropriately based on the over-current protection.
    – Tester101
    May 12, 2015 at 1:58
  • If you're using a double pole GFCI breaker, it will protect both 240 and 120 volt circuits.
    – Tester101
    May 12, 2015 at 2:02
  • Great thanks. And out of interest, if you have a minute lol... Under what circumstances would cause a danger if the neutral and ground were connected together at the thermostat?
    – JoshNZ
    May 12, 2015 at 2:10
  • 1
    This is why it is dangerous... electricity will take the easiest path to ground. By connecting the neutral to ground, you are adding a potential shortcut for the electricity to reach ground through anyone touching a grounded object. When the neutral and ground are connected at the service panel, they are only a quick trip to ground.
    – diceless
    May 12, 2015 at 3:43

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