Mike Tomlinson wrote:
En el artículo , Roger Mills
escribió:

The current socket has 3 x 2.5mm T&E cables connected to it - which
I assume to be two for the ring main plus a spur. The cables all
disappear behind the cabinets (I didn't install them!) and there's
no easy way of knowing which is the spur - other than separating
the 3 and finding out what doesn't then work, etc.

Given that you would have to take the existing socket off to add
another anyway, testing is easy. Power off, take existing socket
off, separate wires, power on, test (carefully!) with a meter to see
which two are live - that'll be the ring. Power off, bit of tape
round them to identify them. The dead wire will be the spur. You can
then add the extra socket into the ring.

I was thinking power off and a continuity test!

--
Adam