What type of damage can power surges do?

Question

I've lived in this apartment for a couple of years and electricity have always been bad (a demand in power from a device systematically causes others to fade off).

I know that a power surge can cause serious/fatal damage to appliances but I'm seeking about the nature and mechanism of those effects.

Specifically, I'd like to know if those events are correlated together and to the electrical variability of the apartment:

1) Micro-wave and fridge recently stopped working (same beaker) at about the same time (fridge compressor didn't die though).
2) Now the PSU of the desktop is making extreme noise and I'm getting pretty convinced that I should stop using it.

So is it possible for power surges to inflict partial damage on electrical devices and if yes, is it likely?

Answer 1

[I]s it possible for power surges to inflict partial damage on electrical devices?

What you refer to as a power surge will most likely be a voltage spike, i.e. short but significant increase in the line voltage. This increased voltage will in the most general case lead to increased electrical currents in your devices, and this may kill them.

Simplest example: a light bulb that is specified for 230V will generate more light at higher voltages (because higher voltage -> higher current -> higher temperature of the filament -> more light), but due to the higher temperature, the filament will break earlier (as early as "instantly" if enough voltage is applied). Other simple examples might be motors which might run faster at higher voltages but will also suffer from the increased currents.

Any devices involving semiconductor circuits (so, almost all nowadays, I guess) are also affected in the same way. Too much current -> too much heat -> broken device. It is quite possible that only a part of a device is affected and the consequences might vary from fancy noises to complete failures.

So yes, it is possible

and if yes, is it likely?

That totally depends on the nature of the voltage spike and the device.

I'd like to know if those events are correlated together and to the electrical variability of the apartment

There's no way of telling this for sure. It might be the case that the dying fridge was causing yet another voltage spike that further damaged the microwave oven, or the events might be completely unrelated.

Answer 2

Yes, it is extremely likely for surges to inflict partial damage. The circuit board is the most sensitive component on most appliances, therefore it is the first to go out in a surge. The compressor on a fridge would be much more robust, therefore requiring a much larger surge to destroy it. Desktop power supplies are known to receive some damage from surges and still work to varying degrees. I've heard of PSUs working intermittently after surges and PSUs that lose some of their voltage regulation accuracy. With that in mind, using a PSU that has gone through a surge could be risky. If it started to give off-voltage to the motherboard and everything else, it could lead to premature failure of other components.

It may be worth it to invest in a good surge arrester, a few surge suppressors, and maybe even a ups for you computer. They can be expensive but not as expensive as the appliances, computers, and data that they can save.