I am installing a D/pole thermostat to a 5000w 240v Garage heater using 10/3 wire and a 30amp d/pole breaker.. question is.. where do hook up the neutral (white) wire too in the thermostat box

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  • Does your heater require a neutral wire? Feb 21, 2018 at 16:23
  • Not sure.. the heater has a black red and green.. all # 10... if I track the green. It is bolted to the frame of the heater.. there is no wire diagram or manual for the heater but a YouTube demo advises it’s a neutral.. this is where I’m confused as I don’t know the difference between Ground vs neutral.. I know the white has to fasten too the neutral bar in the panel but I don’t understand why it will just end up fastened to the frame of the heater if I could just use the bare ground for that.
    – Jason
    Feb 21, 2018 at 16:53
  • Neutral is not ground. Ground is strictly an equipment safety earthing and never flows current (unless someting is failing, in which case it helps circuit protection operate). Neutral is one of 3 possible current-carrying conductors; 2 are required for electricity to work. Your particular heater does not need neutral. The youtube guy is wrong. Neutral should never be connected to ground except at the main panel, which is the official location where they are bonded. Sometimes this is seen a both neutrals and grounds going to the same bar, which is super confusing. Feb 21, 2018 at 17:55

2 Answers 2


A standard 240v heater with no electronics dosent require a neutral the load is pure 240v. All you need are the red, blacks (hots) and the equipment ground. If you had 120v controls you would need the neutral but your thermostat dosent require the neutral so I would cap it at both ends and label it in the panel in case you want to add a fancy controller in the future.

  • Ok.. soooo scrap the neutral (white) and use the ground on the green wire coming out of the heater, that is bolted the the frame.. also ground the boxes and main panel and I should be ok right? I mean my hair won’t stand up.. right?
    – Jason
    Feb 21, 2018 at 19:02
  • Yes that would be the correct way to hook it up.
    – Ed Beal
    Feb 21, 2018 at 19:42
  • @Jason you must cap off the neutral wire at all ends, don't scrap it, don't cut it short because then you can't cap it. If you ever want more power in the garage you could reuse that 10/3 to feed a subpanel (and still feed the heater) but you would need neutral for that. Feb 22, 2018 at 1:31

That type of heater rarely requires a neutral. Double pole thermostats do not provide the capability to control the neutral wire. In the event your heater does actually need a neutral, there is no need to break it. It would not provide a service hazard at the unit. Just pass it through the stat box.

  • You might consider a few more cubic inches to house the wiring for your thermostat.
    – Paul Logan
    Feb 21, 2018 at 17:55
  • 1
    Ironically there wouldn't be a cubic inch issue if neutral hadn't been used. A "surface conduit adapter plate" would buy some cubic inches. I would not pass neutral through, I would unland it from the neutral bar, cap each end, and shove them into the back of the box out of the way. Feb 21, 2018 at 17:57

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