In article .com,
Andrew Thelwell wrote:
Note: This post is talking about UK (220-240V mains supply)

My girlfriend and I recently moved into our newly-purchased house. We
wanted to get the electric meter changed but when the guy came out to
do so, he reported a live reading on the neutral block in our meter
box. This was potentially dangerous, he said, and he called out the
mains engineers. They investigated and couldn't replicate the problem.
They asked if we'd experienced any problems in the house and we hadn't.

My feeling is to trust the engineers over a meter swapper. Those are
simply 'trained' for the one job and usually not even employees of the
electricity supplier.

Since then we've had three occurrences of the RCDs in our fuse box
tripping.

First, can you be clear about this? Most houses only have the one RCD in
the 'fuse box'. So do you mean MCBs (circuit breakers)? An RCD is easy to
spot - it has a test button on it.

I today bought a standard socket tester and tested every
socket in the house. I've found the culprit to be the mains outlet in
our spare bedroom, which appears to be incorrectly wired, showing a
live/neutral reverse on the tester.

I'm afraid that isn't the 'culprit' for anything.

My questions, then...

1) Would this explain both the apparent live neutral reading in our
main meter box and the tripping of the RCDs? I always thought RCDs were
only concerned with earthing faults, not live/neutral reverse polarity
type problems

No and no. RCDs aren't concerned with earth faults - they work by looking
for imbalance in the line and neutral current flow.

2) I've been using the sockets in that room with no real probles apart
from the trips. All equipment (TV, XBox, amplifier, phone charger) have
worked OK thus far. Is the socket likely to be causing any harm?

Unlikely.

3) Is this potentially dangerous?

Yes. A 13 amp lug fuse is in the line for a good reason. With this socket
it is effectively in the neutral.

4) Is getting this fixed a big (and ergo, expensive) job?

It *should* be merely a matter of swapping the wires to the socket.

Your help would be much appreciated as I've had surprising difficult
finding any info about this on the web.

Like all things you have to ask the right questions to get sensible
answers.

--
*The e-mail of the species is more deadly than the mail *

Dave Plowman London SW
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