Diagnosing a ring main installation

[mike004]

Double socket, modern construction with single L-N-E terminals. 2 red wires going to L, 2 black wires going to N, 2 green wires going to E.
All correct and working OK.

But if I remove the 2 red wires from L, and separate them, *both wires* are still live when checked with a neon screwdriver.
What gives? Does this mean the socket is not on a ring main?
I expected one wire to be live, the other not.

Thanks
Mike

 

[dannyboi2003]

See attached link for a better understanding of how a ring circuit works. What you have found is perfectly normal for a ring circuit, a radial circuit would only have one live red/brown cable.

//www.diynot.com/wiki/electrics:socket_circuits:a1_ring_final_circuit

All the best
Dan

 

[Softus]

But if I remove the 2 red wires from L, and separate them, *both wires* are still live when checked with a neon screwdriver.
What gives?

A neon is all very well, but you should also check with a reliable voltmeter.

Does this mean the socket is not on a ring main?

Quite the reverse - it means, usually, that the socket is on a ring.

I expected one wire to be live, the other not.

Why?

 

[SparkyMarky]

If it is on a ring main then both wires should be live when they are disconnected! Both ends of the ring are connected at the consumer unit. If one wire was dead when they were seperated it would indicate either a radial circuit, or a problem (break) somewhere else in the ring circuit.

I wouldn't rely on a neon screwdriver to give you reliable results either, particularly if you're using it to prove a wire dead before touching it...

 

[bananaspark]

a neon once reliably informed me that a ring main cable was not live, however the blinding flash and firecracker bang that ensued as i applied my pliers to the cable made me wonder if the pliers, cable and cu were all conspiring unfairly to disagree with the neon...

find a solid metal hammer and smash the damn thing to pieces, u can then be certain it wont lie anymore

b/

 

[Click-Sure]

They lie, and can be dangerous anyway.

Treated myself to a new CK sensoplus driver set, really nice set of tools, apart from the neon screwdriver which looked like something out of an xmas cracker.

I use my voltage/continuity tester at the very least to check for dead, ideally I use the megger.

 

[ban-all-sheds]

I expected one wire to be live, the other not.

I can't help wondering, if you expected that, whether you're at the stage where you should be taking sockets off...

 

[DESL]

Oh the efficacy of using neon screwdrivers using your body to complete the circuit to test for live lol!!

 

[Softus]

If you have rubbery enough shoes on then you don't need the neon screwdriver.