I have several of them, my favourite is a Sagab Volt Stick Sound, has detection buzzer, brilliant for those out of sight cables.
It's good to know other people have had dramas. My worst one was laying lam floor in a mansion and there was a bouncy floor board underneath. Lifted up could see the pipe running down the wall all good. But Plumber had done some strange pipe work and I judged it wrong. Screw down tssssssss!! Had no idea where the stop cock was. Stressful day that was. I was sweating lol.
I was replacing some underground mains water pipe where there was a mixture of lead, copper and black alcathene pipe . I spent hours hand digging round the pipes and after uncovering the last bit, I went to stick the pointed shovel in the ground away from the pipes, struck a stone and the shovel skidded into the into the alcathene pipe - took out the supply to 5 houses. Quick with two jubilee clips and a plastic pop bottle until I replaced the entire section
Watch "RAW: Workers drill through electric power cable causing a huge explosion at House of Lords in London" on YouTube Could of been worse!
The handyman should have reported this to the clients and renonced responsibility. I've repaired a cable that wasn't correctly installed, I recommend you get an electrician in asap to check. in this case he's not done that or if the cables were correctly installed he should pay for the repair costs.
the handy man should have had the repair carried out himself!! paid for it . He would then have had the invoice to put against his earnings!!!