I have an old house and want to make sure that the wiring for all of the 240 baseboard heating units are still up for the job and not likely to overheat or have any conductance issues. No obvious problems, but just wanted to check. The wiring is from the 60's and the ground wire is fairly thin relative to modern day Romex wiring.

In theory it seems I could hook up a 120v receptacle to one hot wire and use the ground as the neutral and then load test, thought the narrow gage ground wire may cause issues. Alternatively, I could attach one hot wire to the neutral bar and load test and then vice versa. Does this make sense?

Looking to avoid having to buy a very expensive 240V load tester

  • 3
    What is the actual "load test" that you propose? A certain amount of current and check for temperature at...???? Oct 24, 2023 at 2:31
  • You are correct. You have two 120 Volt that combined deliver 240 Volt but also give 120 Volt to the ground each.
    – Traveler
    Oct 24, 2023 at 3:00
  • For Load testing you would use a Watt meter, that will actually tell you the health of the circuit. For that you would turn on the heater and measure using a clamp type (No contact) watt meter.
    – Traveler
    Oct 24, 2023 at 3:08
  • There's a far simpler way to test for problems under load: run it for a while, turn it off at the breaker, then quickly go around and feel all the wires, splices, and connectors; if any of them are hot you have a problem, if they are room-temp or body-temp, you're fine.
    – dandavis
    Oct 24, 2023 at 4:04

1 Answer 1


I see two glaring problems here:

  1. You say ground wire is thin. How thin? If it is visibly smaller than the "load" wire, you risk overheating/burning the ground.
  2. The heating elements are most likely 240V, with no middle tap. That means a coil of wire between two hots, and there is no neutral connected (because there is no need to have it). You can only test and measure them as 240V units to have sense.

For this kind of safety measurements I suggest you contact electrician, who will have proper load measuring tools, and a meter to check insulation resistance. In old house insulation breakdown may be a thing - a professional will check for possible arcing and such.

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