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Definition of 'electrical installation' and requirement to upgrade existing to current regs?

MFr

Hi there

Have found an old damaged 30A JB on a ring final under the floorboards, which I was going to replace - although it spurs to a 2G socket, from which three further sockets are spurred. Obvs you can't have a spur off a spur without a fused connection (which this doesn't have), but is there a specific requirement to upgrade the existing wiring either (a) once the 'non compliant' aspect has been found or (b) as a result of the intervention in the circuit (i.e. does the replacement of the broken JB automatically mean that the spur+spur issue has to be rectified also?).

The wiring is not that old (blue neutral plus other evidence suggests probs 15 - 20-ish years max) so not sure if it would have even been compliant with the regs at the time - but would be pretty difficult to either bring the spurs back to the ring or fit a fused connection due to the location / buried cables etc etc. Might be possible to split the ring into two radials etc (which would probably have incidental benefits) but obvs this is an order of magnitude more substantive work-wise than replacing the damaged JB... 

Cheers

  • 0

    Spurs from spurs, are quite common in practice (go back far enough and two single sockets where permitted on a spur, undoubtedly many of those singles got replaced by doubles over the course of time). Not to mention the usual total botches. The worst I came across was most of the kitchen sockets fed from a 4mm or 6mm cable (lollipop style) - presumably originally the cooker circuit but made redundant when the hob was changed to gas - but then it looks like the old cooker fuseway was pinched for a new shower, so the old cooker cable was redirected into the back of a convenient socket ... which happened to be on a spur. So you had in effect an entire kitchen, including a 2kW oven, washing machine and all the usual kitchen appliances, plus the socket usually used for the ironing, all on one 2.5mm2 cable. It had been like that for years apparently - but had it burned the house down? was it frazzled to a crisp? was it looking a bit distressed? not at all - it all looked fine. (it did get changed all the same though). Has anyone else seen a domestic spur cable looking distressed from overload?

      - Andy.  

  • 0 in reply to broadgage

    acceptable to down rate the ocpd for a ring final to 20 amps,


    Agree, and quite common when the ring has lost its ring and become 'crab claws' or Christmas Tree spurs or similar. This reduces a risk of burning the house down to a risk of getting a bit hacked off because it trips occasionally, and if that encourages a more careful use pattern, that avoids the overload and tripping,  that outcome is very good. If it encourages a call back for a rewire, also good ;-)

    If we really believed a fuse or breaker could never ever be used as a load limiter, then all socket circuits  would be limited to supplying a maximum of 2 and a bit 13A sockets, and or  we should dispense with the 32A breakers as they are superfluous.

    I suspect neither interpretation is what the author intended however.

    Mike.

  • 0 in reply to mapj1
    mapj1 said:
    If we really believed a fuse or breaker could never ever be used as a load limiter, then all socket circuits  would be limited to supplying a maximum of 2 and a bit 13A sockets, and or  we should dispense with the 32A breakers as they are superfluous.

    Yes.

    Wasn't there a time when all sockets were on 16 A radials? In those days, there were no spurs.

  • 0 in reply to Chris Pearson

    Wasn't there a time when all sockets were on 16 A radials?
    Nominally 15A or 5A radials, one per socket, BS3036 style hot wire fuses.

    Even by the 1929 9th edition, that had gone..

     could  have more sockets, Not much later, then earths were also required on new socket circuits, since just after the war - its been a verylong while since one wire one socket, and all that sort of stuff was being taken out from the 1970s onwards.

    Mike.

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