On Fri, 07 Sep 2012 22:51:06 +0100 (BST), "Dave Liquorice"
wrote:

On Fri, 07 Sep 2012 22:17:50 +0100, The Natural Philosopher wrote:

Might be a damaged incoming underground.

Aye, I don't like the description of the sound as a "dull thud" that is
too much like a muffled explosion for my likeing.

Think I'd be getting onto the local REC, even on Saturday. If it is an
underground cable fault it could make considerably more than a dull thud
and a little flicker of the lights.

This is my thinking too.
40 years ago I encountered something very similar the lights dimmed
and there was a thud, but only after heavy rain. In that case the thud
came from across the road under the pavement beneath a street light.

My friends house is on an ordinary suburban street with underground
distribution. Is it likely his incomer cable will enter from other
than the front of the house? If it does enter at the front there is no
chance the supply main runs where I can hear the noise, but it's still
a worry.

I am wondering about the power to the conservatory. If the cable(s)
were undersized and the loop impendence high enough could you think of
some momentary short circuit scenario that would cause these symptoms
but not blow a 30A wire fuse?

It could well be that the problem is next doors, I just cannot tell.


--
Graham.
%Profound_observation%