On Tue, 08 Mar 2011 09:09:02 +0000, MM wrote:

I believe someone was recently talking about voltage spikes, though I
can't find the thread in Google Groups to hang this on. I happened to
be watching my consumption thingy this morning and noticed that it was
constant at 249 volts. Then it went up to 250 for 30 seconds, back
down to 249, then back up to 250 again. For a good five minutes it
hovered around 249-250. Then it came down to 248, then 247.

So only 3v change, depending on the quality of you supply you may
well get a bigger fluctuantion when you drop a decent load on, say
5kW or more.

Aren't these spikes damaging to sensitive equipment? (TVs, DVD Players
etc) I don't worry about the PC because I have a UPS on it. The
voltage is ~supposed~ to be 240 in the UK.

They aren't spikes just norm fluctuation caused by local load
variations, either in your imdeiate vicinty or in your home. The
nominal UK voltage hasn't been 240v for years. See other post. Note
that the "harmonised" range covers the old 240v spec so nothing had
to change. The only comment I'd make about the voltage sitting at 250
odd is that incandescent light bulbs will have a much shorter life.

We used to get through 40W candles in the living room (6 in use
18hrs/day) at about one per month and other odd 60W bulbs at several
a year. Bought a UPS plugged it in and it went straight into "voltage
trim" mode I thought it was faulty! Measured the volts up at 250 or
so, reported it, men arrived in a couple of hours confirmed the
reading and came back a day or two later to adjust the tapping on our
transformer. Voltage now sits between 235 and 245 (was 245 to 255)
and incandescent light bulbs last "forever".

The post about voltage variation was probably mine from the 3rd March
wondering if the grid had had a problem as our volts had risen to 253
for quite long periods overnight 2nd/3rd. Since then things have been
with the normal 235 to 245 range.

--
Cheers
Dave.