I have a subpanel with two circuits on it, A and B, with 4 wires leaving the panel, two blue, one red, one white. The red wire was on circuit A, 20A single pole, and the two blue wires were on a circuit B, a 20A double-pole circuit, with the white going to neutral.

The red wire/circuit A is feeding outlets, while the two blue wires/cicuit B were feeding two 240v baseboard heaters.

I want to disconnect the baseboard heaters to place a different circuit there, can I disconnect the two blue wires and cap them and leave the neutral/red wire running circuit A alone? Essentially the neutral must have been servicing circuit B, so wondering if safe to leave in place when the hots have been disconnected.


  • 1
    A picture of the panel would help a lot. Why are you assuming the neutral was serving circuit B? A 240V only circuit is quite common for heaters. HVAC, clothes dryers and ranges/ovens typically (but not always) use both 120V and 240V and therefore need 2 hots + neutral. Jun 30, 2022 at 18:57
  • Neutral is NOT "common". Each circuit must have its own dedicated neutral. Neutrals cannot be shared. Since the red wire is alone otherwise, the neutral must therefore be with the red wire only. It is not used by the blue circuit. This wasn't clearly marked because it's completely obvious to a pro, but I myself would have put red tape on the white to indicate its association. Jul 1, 2022 at 5:54

1 Answer 1


Circuit A is completely separate from circuit B. The neutral/white must remain for the red circuit to work.

Circuit B does not use a neutral wire for the heaters. One would need to be added if a new device/circuit needed one.

  • So disconnecting just circuit B should be fine then? I assumed for a 240 heater the circuit would have had a neutral wire but if not, then seems this would be ok.
    – Azulith
    Jun 30, 2022 at 19:11
  • 240 volt devices, like heaters, usually do not need neutral. Neutral for 240 volt devices is usually only needed when part of the device needs 120 volt circuit, like a stove with an 120 volt outlet on it.
    – crip659
    Jun 30, 2022 at 19:40
  • If the neutral went to the baseboards it should have been separate and could have been for a temp controller / electronic thermostat in any case the baseboards are being removed so no neutral is needed if it was for control.
    – Ed Beal
    Jun 30, 2022 at 23:32

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