On Thu, 13 Dec 2007 04:40:28 -0800 (PST),
wrote:

We have just moved into a new 1960s house and the upstairs ring main
has been extended into the loft by drilling a hole through the wall of
the back of a socket in one of the bedrooms into the airing cupboard.

2 X 2.5mm T+E then loops round the loft and back to the socket. So..
in the back of my socket I have 4 pairs of wires attached.

When you say "2 x 2.5mm " I presume you mean one piece of cable so the
"2 x " refers to both ends ?

Dunno about the "technicalities" of imbalance etc but it's not the way
to do it IMHO...If possible they should have gone to the socket next
to the one you speak of and removed the connecting cable and replaced
it with a piece long enough to go round the loft and back to the
socket in the airing cupboard,thereby extending the ring .

If that wasn't possible then using a junction box as you suggest would
be my next option and doing that now is presumably your easiest way
unless you can get to the socket next in line and do as I suggested
should have been done in the first place ..