Okay to turn off power at circuit breaker, for just a few minutes?

GreenMntnMan

We just had to have our very ancient oil furnace replaced. New one seems great, and very quiet. Hooray! We have the oil furnace just as back up for subzero weather, as we also have wood stoves and mini splits (and the oil system was in the house when we moved in 25 years ago). So now my dumb question:

There is an electrical junction box basically connected to the furnace, which has a light switch (power on/off for the furnace) and an outlet. The cover plate on the box does not fit flush (the wiring is too tight), so they attached it with only one screw. I have a box extender I want to put on, but I want to turn off the power to the furnace (and box) first at the circuit breaker. This is okay, yes? The furnace will not be running of course (nor will it have been for a long time).

Jamie Hall

No problem

pecmsg

Not an issue.

If it is off for a while do not run the heat pump for the same amount of time.

GreenMntnMan

Thank you both, though not sure what "If it is off for a while do not run the heat pump for the same amount of time" means. Only heat pumps we have are for the mini splits and on the hot water heater, all independent of the oil furnace.

Thanks again.

pecmsg

if you leave the power off for two hours, power it back up and wait two hours before you try to run the heat pump

mattmia2

what @pecmsg means is if you turn the power off to the outdoor unit for an extended period in cold temps, let it stay on a couple hours before running it to let the crankcase heater heat the compressor.

Jamie Hall

If that boiler was wired right, the circuit breaker controls the boiler, only the boiler, and nothing but the boiler… so it shouldn't affect any of the other heating units.

A further thought, though. It's just as well to assume it wasn't, and to use a non-contact voltage tester instead of your fingers to find out if the wires in that box as still alive, in spite of the breaker, before pushing on them…