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For the past three months we had voltage drops in the house and eventually found out that negligence of the power company caused it. It was finally fixed, but my question is, should I or an electrician check for any issues or damage that the thousands of severe drops we experienced may have caused? Could our wiring have been compromised?

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Yes, low voltage can cause damage. Since voltage and current tend to be inversely related, lower voltage results in a device drawing more current. I've seen an air conditioner compressor destroyed that way.

I would take a look at the plugs on any appliances that were running that the time, especially higher current ones like refrigerators. If you see evidence of scorching or melting, have an expert do a more thorough inspection.

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  • Most loads - including air conditioner compressors - are not constant-power loads. (The exception is computer equipment) Commented Nov 1, 2022 at 16:03
  • @user253751 it's not clear to me how that's relevant.
    – isherwood
    Commented Nov 1, 2022 at 16:13
  • Currently and voltage tend to be proportionally, not inversely related, because most loads are (closer to) constant-resistance. A load where they are inversely related is constant-power. Commented Nov 1, 2022 at 16:15
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Well, there are generally 2 reasons why you have power drops from the power company. Both are really on you to detect and report.

A Lost Pole/Hot means that all your 240V loads die, and half your panel goes dead. Except, weirdly, the dead side "comes back to half-life as a zombie" everytime a 240V load is switched on. The classic sign of this is when the homeowner reports that they turn their oven on whenever they want things to work. This is because power is leaking from the live side to the dead side through the resistance of the heating elements in oven, dryer or water heater. In series with the loads on that phase, the water heater will very feebly work, and may be able to reach target temperature by running almost continuously.

However, such problems are usually very apparent and too ungainly to suffer, so people tend to work those problems and fix them PDQ.

The other is a Lost Neutral. This is where the two phases/legs continue to add up to 240V, but neutral is no longer pegged in the middle, so the midpoint "wanders" - 105V/135V, 90V/150V, 80/160V, etc. It usually doesn't go too terribly far because there is a high-resistance back door available: via the neutral-ground equipotential bond to grounds, to the ground rods, to the dirt, to the ground rod and N-G bond and neutral of neighbors and/or the utility transformer.

The upshot is that some circuits see higher than intended voltage while others see lower - and it moves around based on the loads on the circuits. And this can be subtle enough - especially with certain quality LED lights which dynamically adapt to varying voltages - that it can go on for days or weeks without people really realizing there is a problem. And then when they do know there's a problem, the vagueness of it makes them reluctant to fork out money for an electrician.

The power company fixes either one for free.

The Lost Hot is unlikely to fry any appliances, since it only lowers voltage. However a Lost Neutral can rise voltage on the high side sufficiently to burn things out - that's what happened in our complex when we got hit with it, and it took a week for anyone to realize there was a problem, and it was me who found it. (a spoiled Crock Pot batch, and then, "Sorry dear, the toaster IS SLOW today". I immediately grabbed a DVM and sure enough.)

If you are making a case to the power company for fried appliances, most power companies consider that valid. However if they haven't fried yet, they have probably ridden through it just fine. I don't see how it could damage the house wiring, which is rated for up to 0 through 600V. However you might want to replace surge suppressors, as absorbing surges does wear them out.

The newest Eaton GFCI/AFCI breakers trip on abnormally high circuit voltage, to protect equipment from Lost Neutrals. However these can only be put in Eaton, Cutler-Hammer and other panels which state "Type BR" breakrs on their panel labeling.

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