I am converting a large bedroom into 2 smaller rooms by adding a dividing wall and hallway (see diagram).

The large room had a 2500 Watt electric baseboard heater (240V). I would like to use that same 240V line to run 2 smaller heaters:

  • 1100 Watt heater, using the existing thermostat.
  • 750 Watt heater, using a new thermostat I will install.

I am in the US. At the box, the line is connected to a 20 Amp 2-pole breaker.

I assume this is fine as the total load of the 2 new heaters is less than that of the old heater, but wanted to check. Is there anything I'm missing here? Thanks in advance.

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  • Yes, you can put up to 3840W of heaters on that 20A circuit. May 4, 2022 at 20:38
  • What is the voltage of the new smaller heaters all the ones under 1500w that I have installed have been 120v that’s how I answered. But 3840 is correct if it is 240v
    – Ed Beal
    May 4, 2022 at 21:28
  • The voltage of the new smaller heaters are both 240v
    – shackleton
    May 4, 2022 at 23:23

2 Answers 2


Your plan will work. You'll need to pigtail to the first heater and continue the 240V run to the next heater. NB cable can be run in the walls and individual wires in conduit. Check codes to see if you can run NM cable. Many different thermostats are available, many just switch the feed to the heater but they need the same type of wiring as the feed. There are also smart ones and wireless ones so check them out.

  • Thanks very much. Since I have 2 thermostats, my plan was to pigtail from thermostat 1 to thermostat 2. Good call on the wireless though, I will look into that option as well.
    – shackleton
    May 4, 2022 at 20:17

The answer should be yes NEC 220.51 in this case there is not enough diversity in the load electric heat in this case so it is continuous and 1920w max on a 20 a 120v circuit.

fixed space heating is one area that i normally will upsize this is close to the max, or run 10awg from the panel and break down to 12 after the thermostat.

The original thermostat should also be large enough to handle the load but check it’s rating as some ratings really swing with a voltage change some do not it’s all on how it was listed.

I would question 1 thermostat with 2 rooms it is not that much difference to run a feeder from the first room to a thermostat then the 2nd heater.

  • OP said 220V, which should be 240V, but it looks like you may have misread it as 120V. 220V (but likely 240V) @ 15A (and likely it is a 20A circuit) @ 80% = 2,640W. Plus downsizing from 2,500 to 1,850. May 4, 2022 at 22:01
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    I did not say they don’t exist I said I had not installed any small ones that were 240, as I said it is more common to have a 10 awg feeder run 2 units off of 1 thermostat, the thermostat being double pole and each unit only breaking 1 leg because thermostats were not large enough to handle 24 amps but a double pole can break 12 on each leg separately, very common here. Small ones in bathrooms folks don’t realize that 240 is only 120 to ground but 120 sounds safer in a bathroom some cities even have this in there local amendments.
    – Ed Beal
    May 5, 2022 at 13:13
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    Thank you @EdBeal and @ manassehkatz-Moving for the clarification on 240V (I had written 220V). I've updated it above in the original question.
    – shackleton
    May 5, 2022 at 14:23
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    @manassehkatz, but the funny thing is these are hard wired by code and no GFCI is required.
    – Ed Beal
    May 5, 2022 at 19:33

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