K
KFH
Had a call from a plumber I know "I think I have blown the main fuse, there is no electric and no MCBs have tripped".
As he was nearby I went out the main fuse had blown and no MCBs had tripped. He was fitting a shower cubical and was screwing a length of aluminium section to the wall when the top slipped under the cover of the extractor fan when bang and everything went dark.
I checked extractor fan and it was wired OK but his section had touched an earthed metal frame under the cover. After a few checks I suspected that he had put a screw through a cable I got him to put in the screws (power still off) and one had gone through a cable (L + E) but the MCB had not tripped (One of the old Wylex rewirable fuse replacements).
So he had been holding a live 6ft length of aluminium and if he had not contacted the frame of the extractor he would have left a live shower enclosure for the customer to find.
He is going to buy a lottery ticket this week and he was still shaking the following day.
When he dug the cable out it was running diagonally across the wall!
I have the MCB and will disassemble it to see if there is an obvious fault.
I have the job of replacing the CU to include RCDs but am going to have to sort out the wiring/accessories first as the earth leakage was over 100mA.
The cable was imperial 1.0 mm equivalant for an imersion heater and was connected to a 32A MCB for the ring.
It could have so easily ended differently.
As he was nearby I went out the main fuse had blown and no MCBs had tripped. He was fitting a shower cubical and was screwing a length of aluminium section to the wall when the top slipped under the cover of the extractor fan when bang and everything went dark.
I checked extractor fan and it was wired OK but his section had touched an earthed metal frame under the cover. After a few checks I suspected that he had put a screw through a cable I got him to put in the screws (power still off) and one had gone through a cable (L + E) but the MCB had not tripped (One of the old Wylex rewirable fuse replacements).
So he had been holding a live 6ft length of aluminium and if he had not contacted the frame of the extractor he would have left a live shower enclosure for the customer to find.
He is going to buy a lottery ticket this week and he was still shaking the following day.
When he dug the cable out it was running diagonally across the wall!
I have the MCB and will disassemble it to see if there is an obvious fault.
I have the job of replacing the CU to include RCDs but am going to have to sort out the wiring/accessories first as the earth leakage was over 100mA.
The cable was imperial 1.0 mm equivalant for an imersion heater and was connected to a 32A MCB for the ring.
It could have so easily ended differently.