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. So all the sockets are literally connect together to form what
is called a ring mains supply.

"Ring final circuit" is the proper name really. (ring mains are not used
in domestic wiring)

Connecting them together in 30 amp rated block is fine, but then taking a 4
or 6 mm cable to the double socket, would be the proper way to do it. Then
you can safely take a spur off to the new single outlet.

Extending both existing sets of wires to allow them to reach the
existing socket is the way to go. The spur can then be safely taken from
the socket terminals.

But an alternative is to connect the first supply cable (grey cover with red
and black inside) in a lower rated 15 amp block and take new 2.5 mm cable to

15A connectors are not suitable. The current in any single cable in a
ring circuit can exceed that.

the new single spur outlet. From the new single spur outlet, take another
piece of 2.5 mm cable back to the double socket. Also from the double
socket, take another piece of 2.5 mm cable and connect it with a separate
block to the second supply cable.

What you are doing is keeping the whole ring mains supply connecting with
all the sockets again, but now including your new spur off. So your spur
will not be a spur, but part of the actual ring mains supply.

Generally its usually simpler to crimp a connection to one of the
existing cables when joining new socket(s) into an existing ring in this
way since the connectors are physically much smaller. Otherwise you can
run out of box space with four cables to terminate.

http://wiki.diyfaq.org.uk/index.php?...Cable_crimping

If you don't understand any of this explanation, then do it your own way.
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).

--
Cheers,

John.

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