tinned copper strands

[Steve]

When was this last used? I heard 70's mentioned on here before, just wondering as our house was "rewired" 15 years ago, but I found tinned copper behind a socket in our dining room, when it was being plastered. And some of the strands have broken off. Should the whole length be replaced? Or will I be ok just stripping to a fresh bit?

Plasterer took the sockets off, all the wires were loose, and this created a break in the ring. Now hardly any of the sockets work, so there must be at least one more break in the ring, which i've gotta find today.

 

[Steve]

I have stripped the cores concerned back to reveal new core, and terminated these in the socket, but i'm still interested in an age for this cable. And after a bit of searching, I found an FCU, on the ring, whose terminals were totally loose. And I bet its been like that for a long time too, though it was only fitted 3 years ago.

This is one of the bad points of a ring main, you dont know if any cables have come loose, since all sockets (usually) still work, until another break becomes apparent. AND when this happens, it obviously creates a dangerous situation.

With a radial, you always know if a wire has come loose, but it isn't dangerous anyway. I'm beginning to see the advantages of radials now.

I havent tested ring continuity, but after I fixed the FCU above, I tested for voltage on both sets of wires to the socket in the dining room, and both were live at 230 volts. Sorted.

 

[RF Lighting]

I havent tested ring continuity, but after I fixed the FCU above, I tested for voltage on both sets of wires to the socket in the dining room, and both were live at 230 volts. Sorted.

I would suggest that you still carry out a ring continuity tets as soon as you can, as you may still have no continuity on the neutrals or earths, or a high resistance joint somewhere along the line.

 

[JohnD]

You can easily test ring continuity (and conductor resistance) every time you take off a socket or FCU; at any point on the ring, there should be continuity between the LHS and RHS conductor of the same colour. If you make a note of the resistance found you will spot in future if it has changed significantly.

You can't rely on the Earth being continuous like this though as it might be bridging through water pipes.