Andrew Gabriel wrote:

The reason behind that is that rings normally have no spurs when
initially installed, and are extended with spurs. When you get to
the point where it's doubled in size with added spurs, then it's
time to reevaluate the adiquacy of the original design.

Given that this ring was not installed that way, then you need to
use your own judgement to decide if it's time to consider if the
ring is too big and needs splitting or has been hacked around so
much that it could do with reinstalling.

This place is like a little island in time wrt wiring. Original install,
with practically no mods made to it since (one, possibly two extra
sockets added, and one cooker point converted to feed a socket).
Everything else seems much as it was when installed. (even the MK socket
faces which have four securing screws - two at the top and two at the
bottom).

Insulation resistance on the lighting and ex-cooker point circuit was
also ok at 200M Ohm @ 500V (surprisingly!). The ring circuit however
was another matter. The best isolation between any pair of conductors
being 40K ohms! The (inner) cable insulation was visibly disintegrating
and would fall off if the wire was bent about much.


Rubber when it was in good condition actually has a higher insulation
resistance than PVC.

I was quite supprised to find that a couple of the circuits were
basically ok even after all this time. I would guess that the story may
change if any of the cables were moved about too much or stepped on
(currently run loose in the loft - not even clipped to the joists - even
the JBs are not screwed down).


--
Cheers,

John.

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