Ring Main not 'Ring' Main

[vanillasky]

The so called 'ring' main in my house isn't actually a ring main at all. It starts at the consumer unit (obviously) and, after x amount of sockets, just finishes without going back to the consumer unit.
I only realised this when I had removed a socket for decorating and a number of other sockets (the ones 'after' the one I had removed, presumably) had no power. I twisted the two live wires together in the socket I was working on and the remaining sockets all became live again (once power was switched back on).

Is this now common building practice? This house was built in 1995. When I lived in London, the house I lived in was built in the 1930s and the ring mains were actually set out in a ring.

 

[Taylortwocities]

Well, the term is ring final

Ring main is a method of distribution of services (usually water).

There are two types of circuits in domestic situations.

Ring final, as you describe. The standard arrangement is a ring constructed of 2.5mm² twin and earth cable. The fuse in teh consumer unit is 30 or 32amp.

Or a radial. This leaves from the consumer unit and doesnt come back.
Two standard variants: a radial in 2.5mm² twin and earth cable protected by a 20amp fuse
and a radial in 4mm² twin and earth cable protected by a 32amp fuse

Which one of the above do you think you have?

 

[vanillasky]

The T&E used is definitely 2.5mm and it doesn't return to the unit. Not that I can see that it doesn't return but by the evidence given in my previous post.
The fuse at the consumer unit is 32 amp. Presumably, it's a ring final.

 

[Risteard]

The T&E used is definitely 2.5mm and it doesn't return to the unit. Not that I can see that it doesn't return but by the evidence given in my previous post.
The fuse at the consumer unit is 32 amp. Presumably, it's a ring final.

By definition it can't be a ring final circuit if it does not return to the distribution board. It is a radial final circuit which is incorrectly fused if what you have said is correct.

 

[PrenticeBoyofDerry]

A ring final circuit will start and end at the Consumer Unit/Fuse Board.
A radial circuit will start at the CU/FB and finish at the last socket of the circuit.
A ring final circuit will be of 2.5mm2 twin and earth protected by a 32A device
A radial can be either 4.00mm2 T&E on 32A device or 2.5mm2 T&E on a 20A device.

If you have a 32A device on 2.5mm2 T&E radial, this could be potentially dangerous as the cable could fail before the device was activated, so I suggest you have this circuit investigate and confirmed what it is?

A ring final would have 2 line/live conductors terminated to the live terminal of the protective device, but if they are two conductors there, this does not automatically make it a ring final circuit, you would have to confirm end to end continuity of all conductors, it could be possible you have radial circuit that is rated incorrectly with regards to the device, it could also be that the ring circuit has been damaged or broken or it is actually 4.00mm cable and the radial is correct.

 

[vanillasky]

Hope I haven't opened a can of worms here. The T&E is definitely not 4mm. I know 2.5mm when I see it. The circuit, whatever it is and called, is as it was installed when the house was built in 1995 and I would assume that electricians involved with house construction would know what they're doing (presumably). The only changes I've made (apart from replacing some of the painted over and naff white plastic sockets for posh metal ones) is to solder the live wires together and the neutral wires together at each socket so continuity remains whenever I remove a face plate.

 

[EFLImpudence]

is to solder the live wires together and the neutral wires together at each socket so continuity remains whenever I remove a face plate.

That was silly.

PBoD has given you a detailed description of the options so, whether as installed or not, it is up to you to determine if anything is wrong.

 

[vanillasky]

Nothing is wrong. I just wanted to know whether it was usual for ring circuits (or whatever it is they're called) to finish without returning to the distribution board.

 

[Risteard]

Nothing is wrong. I just wanted to know whether it was usual for ring circuits (or whatever it is they're called) to finish without returning to the distribution board.

Not only is it unusual, it is impossible.

 

[vanillasky]

Is everyone on here this pedantic? Jeez, sorry I asked a question..

 

[AndyPRK]

Usually a competition yes!!!!

Although u have been given the answer clearly a while back.

You need to find out if u have a few spurs off a ring, in which case one socket would have 3 cables.

Or maybe a radial incorrectly fused/protected.