LED lights cause appliance failure

DanielKinnear · Oct 8, 2021

I installed 2 LED bulbs into my Genie garage door opener and it caused the microwave to lose power. They are both on the same circuit. When I tested the voltage at the microwave outlet it read 48 volts. That usually means a ground reference problem. Take the bulbs out and the microwave lights up and operates fine. I installed one LED and one incandescent, it works as well.

Any suggestions on a long life bulb preferably LED they don’t cause this issue?

James · Oct 8, 2021

I would try a rough service incandescent lamp. Should last years.

Lucien Nunes · Oct 8, 2021

This doesn't make any sense. Are you saying that a microwave oven plugged into a 120V outlet works OK until you install LED lamps in the garage door opener (powered by the same circuit), at which point the microwave stops working and you get a reading of 48V at its outlet? Measured between hot and neutral? With a multimeter? Does the garage door opener always function correctly?

Losing power at one outlet when adding load at another indicates a high-resistance connection in hot or neutral (not ground, speciifically). But the lamps are a trivial load compared to the microwave so even with a bad connection you would not get this particular effect. Reading 48V can indicate a broken connection in the neutral, because there can be enough capacitance to ground from the disconnected section of the neutral conductor to pass enough capacitive current to give a reading on the meter. The actual voltage displayed is of little significance.

Does the feed to the microwave outlet pass through the outlet serving the door mech? Is it possible that a loose connection in there was disturbed when you changed the lamps, breaking the circuit, and then disturbed again remaking the circuit when you tried different lamps? So that it was not the lamps themselves that triggered the problem but the act of changing them?

I would be looking for something like a burnt wirenut or loose backstab wiring on the neutral in the back of the outlet near the door.