Electrical – Is it possible for a microwave to damage outlets and after a while cause a breaker to pop under load

appliancescircuit breakerelectricalreceptacle

I tried searching for an answer but couldn't come up with what I was looking for, so sorry if this has been asked before!

My wife and I recently moved into a new place which had been recently flipped. We are in a mother-in-law suite so it has definitely had some wiring added and that could be the issue if my question is not possible.

Everything worked great when we first moved in, we were there for about 4 months when we woke up one morning and the fridge was off. Reset the breaker and was off by the time we finished errands. Tried a different plug right next to it and that kept the fridge on.

The microwave is plugged into the same plug so we switched where it was plugged into (now where the fridge is) and it eventually starts popping the breaker. Whenever we needed to use the microwave I just ran an extension cord to the bathroom and left the fridge unplugged since we have an outside fridge (wanted to try and determine what the cause was, guessed the fridge was going bad at first).

Ever since I started using the bathroom plug for the microwave, my wife's hair dryer and sometimes straightener will pop the plug..

The breakers are all brand new Arc-Fault breakers, tried replacing it and that did not resolve anything.

The kitchen plugs all run on one 20 amp breaker, two plugs and one with GFCI. Nothing else runs on those plugs

The bathroom is a single plug with GFCI and is also on a 20 amp arc fault breaker, the bathroom lights also run on that breaker.

I am guessing the microwave is toasting the outlets which is causing possible arc faults? When the breaker is reset it shows the indicator for an arc fault. Currently I am trying out running the fridge on the third plug in the kitchen to see if it will stay on since the microwave has never been plugged into that. I did have the fridge plugged in to another plug in the house for an extended period and never had an issue which is why I am assuming microwave.

Is that even a possible situation?

Thanks in advanced!

EDIT#1:

Well, my experiment failed and the breaker popped.. Only after the fridge had gotten down to temp and was maintaining. The compressor went to kick on again and pop! Will be calling an electrician but advice would be helpful!

Best Answer

It’s funny, when a safety device like an AFCI trips, people are really reluctant to consider that it might be exactly what it says on the tin.

An AFCI breaker detects arc faults - that’s where a wire is either making poor contact and normal current is causing arcing across that poor contact; or; where a wire is partially shorting with another wire (but not flowing enough current to trip the breaker).

A wide variety of wire and device problems can cause arc faults, but top of the hit-list is Backstab connections. And since your house was done hit-and-miss, and very much NOT up to Code, I bet that’s exactly what is going on here. The person used backstabs on the receptacles, and they are failing either because they are backstabs, or that + poor workmanship.

Since circuits are generally wired daisy-chain (breaker to point-of-use 1 to point-of-use 2 etc.), the core problem can be at any point in the daisy chain. When the breaker in question trips, survey which sockets lose power - they all need to be checked. Inspect where the wire attaches. Obviously you can’t inspect where a backstab attaches (and you don’t want to use them anyway), so firmly twist and pull the wire out of the backstab and look for arcing marks/spots. Then put them back on a side screw.

Lastly, if the work had been done by the seller of the house, and is substandard (and it certainly sounds substandard for reasons I’ll describe), then the seller owes you a pile of money. Because the shoddy, obviously non-permitted non-inspected work definitely should have been on the disclosure statements, and was not. I haven’t done enough real estate to know which of the various insurers covers this (title insurance???) but one of them should; they in turn will go after the seller. If none do, then you go after the seller. Shame on them!

Why it seems substandard: Code requires a bunch of dedicated circuits your house doesn’t seem to have.

  • A dedicated 20A circuit for bathroom receptacles, that serves no other loads (except if it serves 1 bathroom it can serve other loads in that bathroom).
  • Two, count em two, circuits dedicated to kitchen countertops, which can power nothing else but a gas range, a clock, or other kitchen/dining area receps.
  • Dedicated circuits for dishwasher, disposal, built in microwave, and electric range obviously.
  • There is no requirement for a dedicated circuit for a fridge, but it’s a pretty good idea. Fridges should never be on GFCI/AFCI, for the same reason fire alarms shouldn’t.
  • Dedicated circuit for laundry room.
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