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I have a weird electrical fault in my house and I have a feeling it’s a super simple solution, so wanted to check here before calling an electrician.

About a month ago for no obvious reason all lights in all three of my bathrooms stopped working. All plugs in bathrooms continued to work. I reset all the breakers in the panel, all the GFCI plugs around the house and nothing worked. So I called an electrician. The day before his visit all the lights came back on and all was normal so I cancelled the electrician visit. I didn’t do anything to have the light back on, they just came on. Now it has happened again. They are off I did all my basic troubleshooting and found no apparent issue. It it was a breaker that needed to be reset manually, the lights wouldn’t have come on on their own... the electrical system is pretty new (house built in 2015), I am located in North America (California). Can anyone help me diy this one out?!

Thank you in advance!

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    clear indication of loose contact, probably on the switch. Did you check it ? does it still gets power,
    – Traveler
    Oct 25, 2022 at 19:44
  • Type and number of breakers and switches that controls the lights? It sounds like like a loose connection.
    – crip659
    Oct 25, 2022 at 19:45
  • next time it happens, unscrew the switch from the wall, and check if it gets power. The process is, Turn off the breaker, unscrew the switch and pull it out some. Now turn on the breaker and check for power. Since it is 2015, they probably used the "Back Stab" method, which is known to make problems. Back stab is where the wires are not screwed with the screws but inserted in the back of the switch
    – Traveler
    Oct 25, 2022 at 19:48
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    Since it's all three bathrooms and all three switches, look for a connection problem at the breaker and where the wires pigtail off the main run and to the bathrooms, assuming the lights or on the same breaker.
    – JACK
    Oct 25, 2022 at 20:13

1 Answer 1

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If you've changed GFCIs, you know that power is typically wired in a string - one outlet to the next, to the next. Technically it's a Tree topology and you can have as many branches as you want (just no loops), but most people just wire it as a "Vine" topology. That's a kind of tree, so whatever.

Safety ground is very important but we disregard it for these discussions.

Most outlets in our vine have 4 active connections: Hot + neutral "in" and 0 or more sets of hot + neutral "out" (usually 1). That is 2, 4, 6 etc. potential points of failure.

Neutrals fail too.

98% of the time, these failures are at those terminal connections. Here's the trick: if the outbound wires fail, the outlet/switch will work (even though the problem is there). The failure is at the last good outlet or the first bad outlet in the string.

Don't miss the hot and neutral connections inside the service panel.

So the answer is try to guess the "last good outlet" and "first bad outlet" and inspect the wires at both. Backstab style connections are notorious for failing and they are also non-inspectable. I wrest them out by twisting and pulling hard, and then visually inspect them for spalling and pitting, which is caused by arcing failures.

Backstab connections cannot be reused (once you release/remove the wire, "the spring has lost its sprung"). How do you avoid a previously used backstab? Easy: never use backstabs ever. Put the wire back on the side screw (or pigtail if there's already a wire there.)

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