I recently drilled into a wire in the ring circuit for my sockets in the wall and blew the fuse wire in the main board. I have subsequently reached the level of removing the plaster and exposing the damaged wire, and have had to cut it and insulate the bare ends whilst I prepare for the next stage ie wire replacement between socket and socket on that part of ring. At present I have put the electrics back on for this now to use the other sockets in the interim. I essentially have two radial circuits coming out of the same fuse point at the moment, but I also know looking at the main board that I only had one ring circuit for the whole house. Should I drop the fuse wire level to 20A (from 30A)for this interim period until the ring is reformed?
I have in the past were errors were made reduce to 20A MCB but using epoxy lined shrink sleeve an a little cable should not take that long to repair.
It is down to a risk assessment and what is the real chance of overloading circuits. In my mothers house I would not worry but in my daughters I would.
I did a excel program ages ago to work out how much cable could be installed in a final ring and a radial and because the max current in centre of ring is considered as 20 amp and 12 amp being even distributed for calculations the total amps is taken as being 26A not 32A when working out volt drop this in turn means that even if split dead centre two radials at 20A instead of one ring at 32A will not be able to have as much cable.
To verify if complies the loop impedance needs calculating or measuring at the last socket. With RCD protection only looking at volt drop but without RCD protection there is a very real danger that a fault will not open circuit within the laid down times.
Where epoxy lined shrink sleeve was not to hand I have used a little silicon sealant inside standard shrink clearly would need leaving open until dry in that case.
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