On 10 Jan, 14:30, Chris wrote:
I've witnessed a couple of strange things in our domestic electrical
circuits recently.

1. Flickering light. I checked behind the switch and found that the
earth wire had come loose. Reconnecting it solved the problem. I'm not
an electrician, but this doesn't sound right to me - I could
understand it it was a loose live or neutral...

a) Did you check _all_ the screws in the switch? Maybe two were loose.
Alternatively you may have a switch on the way out or a break inside
the insulation of one of the other wires and moving things has
temporarily fixed it.

b) Are you sure it was an earth wire? What was it connected to? The
back of the box or the switch itself? If the latter, is this a two-way
switch, i.e. you can operate the light from switches in two places? If
so, the wire you tightened, probably yellow rather than yellow/green,
is actually a live.

2. We have two lighting circuits in the house (upstairs and
downstairs). The fuse blew on the downstairs circuit. All the lights
in the house stopped working, even though the fuse for the upstairs
circuit was fine. Replacing the blown fuse brought all the lights back
to life. Subsequently, removing the fuse for each of the circuits
individually gave the exepect result - only the lights on that circuit
stopped working.

I've known the *bang* of a blowing fuse to jiggle a loose neighbour,
giving the effect you describe. Also, you could have a loose screw in
the fusebox.

Whilst as TNF says, in principle it would be a good idea to have the
installation checked out, you need to find an honest tradesman to do
it, not one angling for a complete rewire, or at least replacement of
the consumer unit. A standard ploy is to say (incorrectly) that the
regs require you to change to MCBs etc., with the scare line that
rewirable fuses (whict it sounds as if you have you have) are "likely
to cause sparks and fire".

I would suggest you either get a knowledgeable DIYer who isn't angling
for a job to look it over for you (does Part P still allow you to
check someone else's installation?) or do some basic checks yourself:-

(a) Get one of the cheap tester plugs that make sure you haven't got
any reversed live/neutral/earth connections in any sockets, and

(b) Go round with a screwdriver tightening all the screws. It's not
unknown for them to work loose with time or maybe the sparks who did
the job had a weak wrist that day. (Chris's rule: If you haven't just
stripped the thread it wasn't tight enough.)

Chris