4 cables in one socket

[ntws]

I went to change an old socket with something newer in the kitchen. I noticed it has 4 cables going in, from the wiring colour I can see the original wiring red and black live and neutrals must be the ring and then there are two newer cables blue and brown live and neutrals.
Looking at it the new cables feed new above counter sockets on one side of the kitchen and one under the stairs socket, they are in trunking above the wall cabinets and then drop down behind the plaster to the sockets. By the looks of it they have tried to extend the ring but made a figure of 8.
I was wondering if I tested the all the live, neutral and cpcs for continuity and providing it was the main ring and another attempted ring if I could connect one leg of the actual ring and one of the attempted ring together in wagos and then the the other two into the socket if this would be ok to do?

 

[jurassic sparkk]

You say four cables feeding it. That seems strange.
Could the old ones be the ring and the other two spurs going to other sockets? You cannot verify without testing.
It would be worth finding out where each cable runs to, or from, then decide how to proceed.

More suspicious when you mention it being in the kitchen.

 

[ericmark]

Yes you can test for a ring final, if a ring and all cables put in block connectors to test, both ends of ring final should show power. Then power off and continuity to show if a fig of 8 or two spurs.

The fig of 8 in centre of a ring not really a problem, only when near the origin can it cause an overload in one leg. However three wires in a terminal is easy enough to ensure good connection to all three wires, but with four one wire may not be firmly clamped, so it is to be avoided.

To extend a ring either a twin back box or grid sockets are the way to go, grid socket shown actually allowed it to be made into a fused spur, within the same back box that was once a double socket, the other way is a double cooker connection unit so you limit the wires in each terminal to no more than three. But either way allows you to have two sockets so one can extend the ring.

To extend a ring final in theroy one needs to test the loop impedance or potential short circuit current or R1 + R2 to ensure the ring is within limits for volt drop and fault disconnection time. A ring needs to have 1.38Ω or less to ensure a type B 32 amp MCB will trip on the magnetic part of the trip. Easy for an electrician with all the test equipment, not so easy for the DIY guy, even the plug in testers with loop, pass at 1.8Ω so only good for a 24 amp circuit.

So the easy method with DIY is the fused connection unit (FCU) of course one should always test, but we all know with DIY testing is likely not to regulations limits, so easier to play safe and use a FCU.

Do be aware a B32 MCB does not always mean a ring final, with 4 mm² it could be a radial, so you do need to test, with imperial sizes hard to tell if 2.5 mm² or 4 mm² equivalent cable is used.