On Wed, 5 May 2004 20:58:32 +0100, Can2002 wrote:

We moved into a new place last December and our surveyor warned us to get an
electrical inspection done.

The outcome of the report showed a number of areas that needed attention,
but one thing that did not come up on the report is that if any high power
device is switched on (e.g. electric shower, drill, oven, etc.) the lights
dim slightly. The dimming is not huge, but definitely noticeable.

I've done a quick survey of each of the MCB's off the consumer unit and
confirmed that the lights (with one exception) run off dedicated fuses.

Am I right to worry about this,

Probably not; If you had an inspection carried out, it would be worth
asking the electrician who did the work if he checked that there weren't
any loose connections on the meter tails.

and if so, can anyone suggest what is
happenning?

Are you in a rural location? Do you have overhead cables to feed you or
is everything underground? Do you notice the dip in the lights when
you're not switching on something in your house? Are there perhaps any
light industrial units nearby?

It could be a loose connection on the mains. If it is noticeable, then
give your local electricity company a call - the ones who maintain the
system - they may not necessarily be your energy supplier and tell them.
There are limits for acceptable step variations in voltage on the
distribution system. They will investigate, usually by installing a
recording voltmeter for a few days. That will show if there's a problem
on the incoming mains and whether it's in acceptable limits.