I just finished tearing my office down to the studs, insulating, and then having drywall installed. The crew did the drywall install today. I have a light switch which is a dimmer that powers 4 "cans" AKA recessed lights. After the drywall install I flipped the switch and the lights came on with a loud POP noise. I turned the switch off and then on again. This time nothing happened for about 5 seconds and then the lights came on. I turned the light off and on about 50 more times and now it always works but there's a low hum that did not exist before. I suspect an electrical short situation was created during the drywall install but I'm not much of an electrician. Where should I look for problems and how should I solve this? Will my house possibly burn down?
Electrical – Possible Electrical Short After Drywall Installation
drywallelectrical
Related Solutions
There are only a few possible causes:
- The newish switch was not wired correctly. I think this is the most probable cause: anything recently changed and not working should be reviewed. Maybe there is a stray strand of wire between the switched terminal and ground, or some wiring fault in the lights. If any of these are the problem, turning on the switch will trip the breaker even if the dehumidifier and other devices are off. That is, turning on only this switch is enough to blow the breaker.
- The breaker has derated itself—that is, it is marginally defective. This happens sometimes, especially with heavily loaded circuits. Breakers get hot, or if they are tripped many times they can experience something similar to heat fatigue.
- The load has increased: more bulbs or more wattage, or the humidifier is using more power. Many electrical systems do not provide steady voltage. If it has increased recently, from say 114 to 122 volts, that might be just enough to increase the power to where the breaker should trip.
If it were me, I would
- Shut off the circuit
- Pull the "new" switch and examine it for physical problems.
- Use a DMM to check for continuity between the black wire and ground: there should be none—that is, the ohms should be infinite.
- Disconnect the white wires (should be a wire nut in the switchbox) and check for continuity between white going to the lights and ground: should be none. The ohms between the white wire going to the breaker panel and ground should be close to 0.0.
- Check the resistance of the light circuit with the DMM between black and white. For 120 watts incandescent @ 120V, should be 8–10 ohms (cold tungsten has its resistance of about one fifteenth its hot temperature).
If the problem had not been found after that, I would reconnect the white wires (undo step 4), turn on the breaker, and put a clamp-on A.C. ammeter (actually an analog meter would be better for this test) to measure the current on a black wire, and turn the switch on. It can either spike strongly or not at all. Strongly is bad and means there is a fault in the wiring or fixtures. Not at all means more tracing of wire, perhaps from the circuit breaker panel is needed.
You need one or two 3-way switches with pilot lights. These are also called 3-way switches, illuminated ON. Some have an illuminated toggle, some are decorative style and some have a separate light. These are examples (not that none of the ones shown below are actually 3 way switches)
These switches generally need a neutral wire at both switches. Conventional unlighted switches do not need a neutral. They also need three wires (other than neutral) running between the switches.
If you only want the pilot light in one location, you still need two 3-way switches, but only the lit one needs a neutral.
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Best Answer
This sounds like a rather dangerous situation. The drywall installers no doubt did not install metal straps on the studs wherever an electrical wire crossed through the stud. Most likely a drywall screw or nail has gone into the stud and entered a wire that crossed the stud in the same place.
The fix for this may require a professional electrician unless you are pretty familiar with electrical wiring work. It will be necessary to cut the power to the circuits and open all the applicable electrical boxes and disconnect the various lights, switches and power feed wires. Then shorts checks can be made using an appropriate ohm meter for all the wires in the area between the boxes.
Once the short is located it will likely be necessary to remove the drywall in that area to replace the wire.
Do not leave this problem go. It sounds like you have a medium resistance short in some wire/stud crossing. I say medium because you did not mention that it is tripping a breaker. The resistive short can produce a lot of heat and could definitely lead to a fire in your wall or ceiling.