The agent phoned this morning and asked if I could have a look at another property, downstairs ring tripped on Sunday. One of their regular sparks attended yesterday and declared the RCD faulty and replaced it. When it tripped again last night and still fails this morning he was not available.
Sure enough the B32 RCBO has been changed and the removed item laying on the floor of the cupboard.
Tenant sat on my shoulder as I worked, megger showed 11KΩ L-E, N-E and 30KΩ L-N. Removed all plugged in devices from dead sockets and confirmed there are no more sockets or switches.
"Other guy didn't do all this or use a tester."
I started breaking the ring down and quite quickly found it faulty between 2 sockets and where I believed no other devices existed. Asked again if there are any more sockets, especially between those 2.
At that point I terminated all cables except the faulty bit so the washing machine and kettle could be used (Identified as on each half of the ring).
At their insistence we sat outside for tea and biscuit, then it was mentioned what gardening was being done the previous week and I was taken outside to see.
To see this:
"Oh yes that old light was removed years ago."
A gentle tug found the end of the cable:
BTW it rained hard on Sunday when the circuit tripped.
I retested the link between the sockets to find the fault resistance had gone way up, Iwas able to trace the cable to a FCU upstairs and switching it off removed the fault. Isolating the FP200, pulling it into a 'loft space' and labelling it was easy.