ring main
- Thread starter leepy
- Start date
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B
breezer
if you know that only half the ring is live and you know this is not right, you should also be able to figure that the ring is broken, but where is anyones guess.
I would suggest at the most recent socket.
as for your fcu question yes you can, but obviously the max load is 13A
I would suggest at the most recent socket.
as for your fcu question yes you can, but obviously the max load is 13A
B
breezer
switch mains off check all sockets, use a meter for continuity test between sockets, if not rip up floor and have a look 
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It might be that you did not break into the ring, but into an existing spur with a further spur coming off it.
I take it you have dissconnected the cables at one socket and found that one is live, and a second is not. I would take suitable precautions to prevent these live wires from shorting on anything, and then go round all sockets on this circuit and see which ones are live and which not. You could use a table lamp if you do not have anything more sophisticated.
A broken wire or loose connection might explain this. If so it is most likely where there is a connection, so behind a socket or if not then a junction box.
I take it you have dissconnected the cables at one socket and found that one is live, and a second is not. I would take suitable precautions to prevent these live wires from shorting on anything, and then go round all sockets on this circuit and see which ones are live and which not. You could use a table lamp if you do not have anything more sophisticated.
A broken wire or loose connection might explain this. If so it is most likely where there is a connection, so behind a socket or if not then a junction box.
You had best check the other dead sockets and see if each has two wires coming in to it.
It should not be a radial wired on 30 Amp rewireable. But it is not out of the question that someone has installed a long multiple unfused spur starting from the ring. If so, one of the dead sockets should now be on the end of the chain with only one wire going into it.
Alternatively the ring has broken. This might be a bad connection at the last dead socket, or at the first still working socket past it. Or somewhere between them.
If you have the knowhow you could test ring continuity from the ring cables in the CU. This would tell you if there is a ring. If live is broken somewhere you would find no connection from live in one cable to the other, but earth and neutral should most likely connect. If all three are ok from the consumer unit end, then you know you have found a spur, or some other strange arrangement.
It should not be a radial wired on 30 Amp rewireable. But it is not out of the question that someone has installed a long multiple unfused spur starting from the ring. If so, one of the dead sockets should now be on the end of the chain with only one wire going into it.
Alternatively the ring has broken. This might be a bad connection at the last dead socket, or at the first still working socket past it. Or somewhere between them.
If you have the knowhow you could test ring continuity from the ring cables in the CU. This would tell you if there is a ring. If live is broken somewhere you would find no connection from live in one cable to the other, but earth and neutral should most likely connect. If all three are ok from the consumer unit end, then you know you have found a spur, or some other strange arrangement.
We getting into exam questions here?
Most probably, nothing.
The cable rating depends upon exactly where it is run....how much it can dissipate heat. As long as it does not actually run through insulation it is probably ok to carry 20-25 A. Above this it will heat and the insulation will slowly degrade.
What you (may) have is a ring divided in half, each half rated to carry 20 or more amps. There is only 32 A available altogether, so there is a reasonable chance that:
1) the circuit never actually got near its 32A limit so never overloaded anything
2) Even if it ever got seriously going, the load was divided between the two parts so neither exceeded its rating.
3) even if it did, circuits are designed for occasional overloads.
The most likely place for a problem would be the kitchen, if everything was on the same half of the ring.
However, If the ring is only broken in one conductor, then return current would still be using a ring. Which would increase the effective cable capacity to around the full 32A mark.
Oh, and you are planning to add another 13A load. Guess that means you reckon there is spare capacity out of the 32A . Most probably a good bet, but I would recomend a separate kitchen ring when someone has the choice.
Most probably, nothing.
The cable rating depends upon exactly where it is run....how much it can dissipate heat. As long as it does not actually run through insulation it is probably ok to carry 20-25 A. Above this it will heat and the insulation will slowly degrade.
What you (may) have is a ring divided in half, each half rated to carry 20 or more amps. There is only 32 A available altogether, so there is a reasonable chance that:
1) the circuit never actually got near its 32A limit so never overloaded anything
2) Even if it ever got seriously going, the load was divided between the two parts so neither exceeded its rating.
3) even if it did, circuits are designed for occasional overloads.
The most likely place for a problem would be the kitchen, if everything was on the same half of the ring.
However, If the ring is only broken in one conductor, then return current would still be using a ring. Which would increase the effective cable capacity to around the full 32A mark.
Oh, and you are planning to add another 13A load. Guess that means you reckon there is spare capacity out of the 32A . Most probably a good bet, but I would recomend a separate kitchen ring when someone has the choice.
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