Got a call out last night (tripping RCD). Narrowed it down to one particular socket circuit - 3 cables into MCB r1 0.43 - rn 0.44 - r2 0.69 (r1 to r1 of spur 23k WTF!!) and that's with the earths an neutrals disconnected also!!
Checking IR I got 0.01 L-E on the ring and started to try and locate the fault, after splitting the ring at some sockets I still had a fault at 6 sockets, I disonnected these and they still had a low IR!!
All bar 1 or 2 sockets had 2 cables and are not spurs!! god knows how many JB's and their configuration lies under the suspended floor, also cables are old imperial PVC so I have recommended a rewire.
Checking IR I got 0.01 L-E on the ring and started to try and locate the fault, after splitting the ring at some sockets I still had a fault at 6 sockets, I disonnected these and they still had a low IR!!
All bar 1 or 2 sockets had 2 cables and are not spurs!! god knows how many JB's and their configuration lies under the suspended floor, also cables are old imperial PVC so I have recommended a rewire.