The overhead light went out in my laundry room, my wife replaced the bulb and it still did not work. Then she plugged in the vacum cleaner further down the hall, (away from the breaker box) and the dining room and kitchen lights also went out. I've had this problem before but only with outlets. with outlets I could trace the problem back to the last hot Outlet and replace/attatch ground. This would solve the problem. THIS problem involves several switches and a three-way switch. In theory, can I open up all the wiring, checking each feed until I find a hot feed and replace that switch?
It may not be a bad Switch but it could be just a wire loose in a wirenut. You have the right idea, to open up each box on that circuit and check for loose connections. A bad switch would only affect the light attached to it while a loose wirenut/wire would affect down the line on the same circuit.
If you try this and need more ideas come back and ask away. I'll walk you thru troubleshooting until we find it.
I've already replaced all the switches and the light fixtures. I tested the connections to the switch/fixture, but I get no reading on either a circuit tester or multimeter. I have not yet dragged all the wiring out of the box and tested individual cables. The wiring for a threeway switch is kind of throwing me off. I have opened up the Panel and get power there.
Assuming you don't have any buried junction boxes concealing wires the problem should be in a box somewhere. We know it starts at the panel and goes to the lights. Now we have to find the bad connection.
Is there any power in the switch boxes at all? Have you tested the wire connected to the breaker that feeds this circuit? For part of this a multimeter is good to use and for other parts of this a non contact tester is good. I have one pictured here.......
This tester beeps or ticks when it is put near an energized wire and it is very handy just for that reason.
I tested the black wire at the breaker to the white wire at the top left of my split-bus box. I got 118.8Vac on my digital multimeter set to 200Vac. Did I bypass the breaker by doing this? I don't believe so but am not sure.
There may or may not be power in the 1st switchbox from the panel. The 1st switchbox is a threeway switch for a hallway light. There are no wirenuts in my house and most of the grounds are tied together and crimped.
Ok, you know your breaker is working OK, that's good. All of the grounds should be tied together and crimped, this is good as well. You can test from the black terminal on a 3 way switch to the white or the ground, either should tell you 118 volts. The first switch in the 3 way circuit should be hot all the time, the last switch in the circuit is only hot when the circuit is completed. One or the other of the travelers, the other 2 wires on copper screws, is going to be hot all of the time. Switching a 3 way switch simply swaps the copper screw connected to the black screw inside the switch.
If there are no junctions, wirenuts, in these boxes I'm wondering how joints are made to join hot wires to feed multiple boxes. Are by chance the stab connections and screw connections both used on the switches? Stab connections can fail in these devices and be the cause for an outage like this. There could be Voltage with no load turned on but no voltage when the switch is turned on. Check these black wires for electricity to either the white wire or ground wire. It's tedious but it has to be done one step at a time.
Electrical contractor and electrical inspector for over 23 years with phone and networking expertise
Okay that helps I'll start pulling things apart and checking individual wires this weekend. Most of the switches and outlets are the stab in type, whoever wired my house (back in the 50's I think) didn't use wirenuts in the box, instead he used a brown tape that is similar to e-tape. I've had several problems with the stab in outlets, and have been replacing them as I go.
Brown tape does not give the mechanical connection required by the code and just good electrical practices. Use wirenuts and I'm sure your results will be better. Feel free to come back with more on this topic if you need to do so. I'll be here to help you.
FIXED IT!! Pulled apart both of the three-way switch wiring. All of the brown tape connections had a copper crimp ring under them. I spent 1/2 hour in the attic with a pencil-tester checking everything from the 3-way back. All dead. Swam through blown-in insulation for 10 minutes REALLY expecting to find the problem.
NO such luck.
Pulled apart the furthest box that did not work. 4 white wires crimped and taped. 3 black wires wire-nutted. a bare black wire right next to the wire nut. I knew as soon as I saw the bare black wire I had found the problem. What I don't understand is how the last thing from the panel can make everything before it not work. As soon as I saw the bare black I knew I had solved the problem, I pulled the wirenut off the other three blacks and had my wife flip the breaker, the one that was no longer connected was the hot one. When I put a wire nut on I tighten it until the wires twist. On inspection this wire had marks for the wire nut it was next to, but it wasn't hooked up.
Great. That's good to hear. Congratulations!