I am remodelling my apartment and purchased some new baseboard heaters to install. Before installing the new ones I thought I should check out the existing wiring. It is only a small unit and the total of six existing heaters are fed by two separate circuits. One circuit acts as it is supposed to do (120V to Ground, 240V between Red and Black, or in this case White and Black, being old wiring). However, with the other circuit there is no voltage differential between ground and black and the heater casings are all live. Heaven only knows how long it has been like and thankfully no one has been shocked.

I then started going through each terminal box in the circuit to look for faulty connection but could not find any. Then I began disconnecting each leg from each other and eventually found that the first heater (in the circuit) is good if disconnected from the others but the ground becomes hot once the next leg (in fact, a junction box that serves a thermostat for the second heater) becomes live. In the absence of any faulty connections, I am thinking that there must be something like a nail through the wiring (behind the drywall) that has caused this fault. Does anyone have any other suggestions as to what I might test? Also, do I have many otpions other than to start ripping out drywall and pulling through new wires?


Of course, no circuit breaker has tripped, despite this fault. Presumbably because the panel is just seeing normal current flows?

All suggestions welcome.

Where is this located and do you own the unit?

Yes, I own the unit and it is in British Columbia, Canada.

the heater casings are all live.

What does that mean and how do you know?

It means that when I put the neon tester to the housing and or the ground termnal it is indicating that it is live (hot). This is confirmed by the fact that a multimeter is confirming no voltage differential between positive and ground.

Not trying to be difficult here but;

By neon tester do you mean a neon test light or a no contact voltage sensor?

There is no negative or positive in ac current. There is a hot and a neutral. In a 240 volt circuit there is no neutral. Both conductors are hot.

There should course be 240 volts between conductors. That is if the thermostat is not satisfied. If the thermostat is double pole there will be not voltage between the conductors or between either conductor and the ground if the thermostat is satisfied. If the thermostat is not satisfied there will be 240 between conductors and 120 between each conductor and the ground.
If the thermostat is single pole, there will always be voltage between one conductor and the ground. If the thermostat is satisfied there will be no voltage between the two conductors and there will be not voltage between one conductor and the ground.

Thank-you for correcting me - in fact I seem to have a two pole thermostat (and not a four pole thermstat), with the three white wires tied together and the black switched, which made me think of neutral and live (the british terminology). You are quite correct, both the white and the black are live (hot). Anyway, the good news is that I took apart every single connection on the circuit and rewired them one by one and the problem seems to be resolved... 240V between white and black, 110V between ground and each line, and no neon tester telling me that the ground was live (hot). There must have been a faulty connection there somewhere but I never did figure out which one it was. I am just happy then I do not need to start pulling the drywall apart...