In article , RB wrote:
It's unlikely from you description that the power company is
instantaneously increasing the voltage to your house. What may be
happening is that someone else is loading down the transformer that
supplies your house and when the unload it the voltage increases. If
this load were on just one side (120 volts) that would explain why only
some circuits are not affected.

The best solution is to get a recording voltmeter and put it on each
side of the line for a day or so each to see exactly what is happening.
SNIP
Cheryl wrote:
Hello. It's possible I can't give enough information here for a
diffinitive answer, but I'm asking anyway. My lights and other
electrical appliances have recently been experiencing surges of
power; lights go brighter, refridgerator goes louder, etc. I'm afraid
this is going to damage something, or cause a fire. I've called the
power company and their annoying automated messages state that
flickering lights (etc) are usually caused by interier wiring, yet
others I've spoken to say that nothing can cause EXTRA power to be
supplied to the affected appliances, diminished yes, extra (surges)
no. It also doesn't effect one or two circuits, either, but pretty
much the whole house. Should I contact an electrician, or have the
power company come out and inspect? They say they'll charge me $80
for the visit if the problem isn't in their wiring, and they might
not be able to resolve it for that price.

I would have an electrician check for a bad neutral connection in the
breaker box or further upstream. If it is upstream of the electric meter,
depending on your jurisdiction you may get the electric company to fix
this or pay for fixing it.

Symptoms of a bad neutral connection or an open neutral are some lights
and appliances receiving excessive voltage, often others getting low
voltage, and voltage changing noticeably when some heavier loads or
sometimes even lights are turned on or off.
If you mix loads of different power factors in a house with an open
neutral, it is possible to have all circuits have excessive voltage or the
two sides of your incoming power line to have voltages adding up to more
than 240 volts. But I think usually you will find some loads
undervoltaged and some loads overvoltaged if you have an open neutral.

If you have an open neutral, it is a fire hazard because overvoltaged
appliances may catch fire.

If the breaker box has lose screws that are not holding wires properly,
you can tighten them. Be careful and use a screwdriver with a good
plastic handle and don't touch the metal part, and you increase your
safety from electric shock if you stand on a plastic plastic milk crate or
a piece of known good very dry non-decayed wood. Do not stand on
anything unstable - you may grab something live if you start to fall! The
incoming wires are not shut off by the main breaker, and one of these may
be loose. The neutral bus may have voltage on it if the incoming neutral
wire is loose or not connected.
Call an electrician if you do not feel up to checking that screws in
your breaker box are tight.

- Don Klipstein )