Cable drilled but didn't blow any CU fuses

[NewOrder]

A few months back my dad was drilling into the a door frame and then I heared a little bang and everything electric just went out. I had bought a new phone at the time so I was too busy playing with that to bother with what my dad was doing (I have one of them testers to see if live cables are burried under things).

I quickly realised that the service fuse must have blown and took the door frame of to discover all the wires from the CO were burried underneath it

Luckily the cable he drilled throguh was just for the extractor fan in the bathroom (on the old immersion heater circuit) so I simply disconnected it and that was the end of that.

We phoned the electricity board and they replaced the fuse free of charge although it took me a long time to convince him that I had isolated the correct circuit.

The 3amp fused connection unit did not blow, nor did any fuses is the consumer unit, so what could have caused the short to be so bad it blew the main 420v service fuse? For a second I thought my dad had wiped the entire street out

 

[davy_owen_88]

The 3amp fused connection unit did not blow, nor did any fuses is the consumer unit, so what could have caused the short to be so bad it blew the main 420v service fuse? For a second I thought my dad had wiped the entire street out

That scenario should never happen but one possibility is that the service fuse was duff, the second is that the cable your dad drilled through was connected directly to the main switch and therefore has no overcurrent protection and the other is that the fuses in your consumer unit are actually nails or something Oh, and thinking back to a photo RF posted a while back, the fuses could be wired up incorrectly - ie the circuit cables are fed from the same terminal as the busbar which is bypassing the fuse completly...

 

[NewOrder]

This is what is worrying me as both seem impossible as switching the electricty off turned of the fan, so it must have been wired into the consumer unit, secondly I know all the fuses are correct I made a point of checking last year, and a fuse did blow many years ago when some plaster fell apart casuing the earth to become live.

It sounds like it is a bit worrying though, I want to pay for an inspection but my parents think its a waste of money as there is nothing wrong with electrics, but we all know that there could always be a disaster waiting to happen if it works fine.

 

[lazygit]

The 3amp fused connection unit did not blow

,
The 3A fuse would only blow of the load side was shorted. If the supply to the fuse is shorted a fuse will go further upstream

 

[Lectrician]

A 3036 fuse in the CU?

And a fault a meter or so from the consumer unit?

Falt current would be high.....

A 1361 may well operate before the 3036.