I am trying to help some friends discover what is wrong with their
electrics.

The last 3 or 4 times I have visited them I have heard a thud, and the
lights blink at the same moment. This happens maybe twice per hour,
but not regularly enough to be able to predict the next event.

My friends had not attached any significance to these events until I
called them catastrophic explosions, now they are worried. They hadn't
noticed the lights flicker at all, they had heard the thuds but put it
down to their neighbours door slamming, which isn't unreasonable
having heard it.

All the circuits are affected, lights and power.

For the record, his consumer unit is an old MK type with rewireable
fuses, one lighting cct has a retrofit 5 or 6 amp MCB, one of the
later lever type.

There is no history of any fuse blowing.

The house is a semi, the meter and CU are in the hall cupboard far
away from the party wall.
The supply incomer, I imagine, enters from the street.

The bangs however seem to emanate under the floor at the back of the
house near to, or maybe even beyond the party wall. The elderly lady
next door says she hasn't noticed anything.

There is a conservatory with a solid floor at the back of the house.

I thought water would be involved, and we have had torrential rain
recently, however not a drop has fallen this week and I witnessed 3 of
these events last night.

I have an idea or two of diagnostic measures to try next time I visit,
but what does the team say?


--
Graham.
%Profound_observation%