On 2 Nov, 01:32, John Rumm wrote:
BigWallop wrote:
No. *What I mean is. *You should have two cables supplying the double
socket. *These two cables connect from one socket to the other right round
the house.

*snip

But be aware of the limitations of the safe loading on your new spur.

There are no limitations of loading on a spur that you need to keep in
mind really. If the spur is unfused then it can supply at most one
single socket. That in itself limits the maximum load. (for more than
one double socket you would require a fused spur - an hence a total load
limit of 13A imposed by the fused connection unit).

This maybe needs clarification.

The rules SFAIUI are that a single spur - normally in 2.5mmsq cable,
unless its route etc dictates a larger size - can feed only one
fitting, but that fitting can contain either a single 13 A outlet or a
pair (ie double) of outlets.

This is because a double 13A socket is counted as a single 13A fitting
for assessing circuit loading (or at least was in the 16th IEE regs).

To feed more than one fitting on a spur, a fused connection unit must
be wired into the spur. This may be placed anywhere along the spur
before the first fitting. The fuse rating may be up to 20A, (but is
often only 13A) as 20 A is the limit current for 2.5mmsq cable.

Two tentative suggestions which came to mind when I read the OP:

(a) dig out the old metal backing box & replace it with a 45mm deep
one to give more room for a cable connector (which needs wrapping
insulation tape or some other isolation from the other contents of the
metal box & socket)

(b) replace the existing socket from which the spur is being taken by
2 separate sockets (both could be either single or double) in line
with the ring cable to provide spare connection cable from the ring.
Make sure the spur cable is aligned in one of the safe vertical/
horizontal zones of the new sockets & connect up, joining the 2 new
sockets with a short extra length of 2.5mm sq cable.

If it were my problem I would probably have used (b) as the end result
doesn't look botched & it gives more socket outlets of which I find I
never have enough.

HTH