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Wiring two baseboard heaters

Hello all, so I was wondering if this is possible. I have one wall thermostat that I want to wire to two baseboard heaters in two seperate rooms. The second heater would have it's own built-in thermostat. Would they work seperate of each other or would the main thermostat control both heaters? Thanks in advance


  • mattmia2
    mattmia2 Member Posts: 8,866
    What kind of baseboards are these? Are they electric baseboard heaters or some sort of hydronic baseboard controlled by a zone valve or pump relay? I assume electric but you did not state what they are.
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,377
    edited October 2019
    Depends on how you wire it, assuming electric also.
    Seems like you want 2 different things at the same time.
    If they both have thermostats why do you want one to control both, and when do you want them to be controlled individually.

    If room A is always colder than room B, then wire them in series-Room A thermostat, Room A baseboard, Room B thermostat Room B baseboard. That would turn off room B when it comes up to temperature and allow Room A to keep heating.
    However Room B never runs without Room A.
    Of course you need to make sure you have the proper size wiring and circuit breaker.
  • Jamie Hall
    Jamie Hall Member Posts: 22,147
    There's more here than is immediately obvious. First question: are these heaters electric, and, if so, are they 120 volt or 240 volt (I'm assuming you are on the North American side of the pond here; UK/Europe is all 240 anyway). If they are 240 volt, your thermostat must, according to code, interrupt both hot wires (if there is a neutral, it must NOT interrupt that wire).

    Now that said... the heaters themselves are loads. They cannot be wired in series. If you want either thermostat to control both heaters, then wire the two thermostats in series and take the hot feeds from the second thermostat to both heaters in parallel. If you want one thermostat to control only its own heater, but the other to control both, then take the hot feeds from the control both thermostat to the heater which you want to control from it and, in parallel again, to the thermostat which you want to control only its own heater and thence to that heater. If you want the two heaters to run independently -- which it almost sounds as though you do -- then take your hot supply to each thermostat independently.

    Obviously if these heaters are 120 volt, then you have only one hot, but the principle is the same.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England