"Ade" wrote in message
...
did gone and wrote:

"Ade" wrote in message
...
t'other day, I changed an ancient bakalite single socket, for a new
plastic dual socket. The socket is in a garage, and is the only socket
attached to a mumblety amp breaker (I forget the rating).

Prior to me doing the swap, the user has reported that a couple of
times, testing the lawn mower RCD has also tripped the main house RCD,
which must obviously be re-set before anything works. I managed to
replicate this behaviour once, but subsequent tests seemed fine. I also
noticed, after I had switched the socket off at the breaker, that I
still had 10v AC reading on the multimeter.

Since the wiring is literally meter - breaker box - this socket, I
don't understand where the 10v could be coming from...

Anyone got any ideas?


I would not worry about the 10V showing on a DMM.


I am no longer worried. I wasn't that worried anyway, I didn't get any
shocks or see any sparking while working on the wires, which would
normally be a giveaway...

However something is missing here.

What RCD is on the lawnmower?

Dunno, it's one of those plug in ones, I didn't get the brand. So you
have socket - RCD - extension lead - mower; personally, I don't see
the need for it (as the house wiring now has an RCD, it didn't before
the consumer unit was fitted).

If the garage is now protectected with a 30mA RCD supply then there is no
need for the plug in lawnmower RCD.

The lawnmower RCD will trip at the same time as the one in the house and
take out the house RCD.

Cheers

Adam