On 01/04/2013 16:10, Roger Mills wrote:
On 01/04/2013 15:50, Dave Plowman (News) wrote:
In ,
Roger wrote:
Yes, several! I was thinking in terms of having to disconnect the
circuit at the consumer unit in order to trace it - but it's now obvious
that I don't need to do that.

Easiest way is just to disconnect the earth wires, then find out which
one
is connected to the spur socket, by probing a fixing screw on that. If
you
can see which TW&E it belongs to, you have your answer. But you do
need to
measure a dead short on your DVM, rather than just any old reading.

The only problem is that I don't know where the spur goes! I don't know
whether it powers a socket or something like the cooker hood, or heated
drawer.

But, as others have said, if I power down, disconnect all 3, power up
again and check which 2 wires are live, I will know which is the spur -
regardless of what it does.

The other "tool" which can be handy is the socket tester thingy which
looks like a 13A plug but has three lights in it. I've butchered one of
these to terminate in three leads with croc clips on. Particularly
useful on lighting roses but also useful here as it will reveal things
like missing live or missing neutral on one half of the ring-main.

If you don't want to butcher one you could temporarily connect each T&E
in turn to a spare single socket for testing.