Cut into live mains cable with metal stanley knife..

[User1234567890]

It was all going so well! I've removed the old plaster in my hallway back to the brick in places, and filled all round the edges with foam, mortared the old brickwork and I was just trimming the excess foam off and bzzzzzzt, right up my arm. I feel OK, index finger is a bit hot, and no sign of anything else going on, but that was close!

Whoever wired this up (Wasn't me), has wedged the cable between the front door frame and the plaster/brickwork so only the very edge is visible. There's some kind of thick rubberised (might be tar) sheet and I thought this cable was that, and just trimmed it, as I have done a few times this week .I'm going to need to fix this length of cable before my plasterboard goes on. Should be OK with a simple low profile junction box and remove the damage and joint back together? Any recommendations for a flat as possible junction box, or other ways to rejoin the cable safely, long term, that are low profile, as in under 20mm if possible?

 

[accelerator]

Maybe buy yourself a cable tester for the future?

 

[simplesteve]

And a fresh pair of underpants ?

 

[Ollyfp]

Lucky boy! A few years back I was adding sockets to a ring main. I'd left the radio on as a reminder that the power was on. My brain somehow reversed this message and as I was singing along to Dio, I happily cut through the cable. There was a loud bang and I shook violently for about 2 seconds before the cable and cutters jumped out of my hand.
You only get away with it once!

 

[User1234567890]

Maybe buy yourself a cable tester for the future?

I've got a Bosch one, but this wall has got gas pipes and all the electrics for the house, so lots of false positives, as well as positives. The wire was wedged between the door frame and brickwork, so pretty much invisible until I cut into it. Just didn't spot it. Maybe better specs would do the trick

 

[Ollyfp]

It was all going so well! I've removed the old plaster in my hallway back to the brick in places, and filled all round the edges with foam, mortared the old brickwork and I was just trimming the excess foam off and bzzzzzzt, right up my arm. I feel OK, index finger is a bit hot, and no sign of anything else going on, but that was close!

Whoever wired this up (Wasn't me), has wedged the cable between the front door frame and the plaster/brickwork so only the very edge is visible. There's some kind of thick rubberised (might be tar) sheet and I thought this cable was that, and just trimmed it, as I have done a few times this week .I'm going to need to fix this length of cable before my plasterboard goes on. Should be OK with a simple low profile junction box and remove the damage and joint back together? Any recommendations for a flat as possible junction box, or other ways to rejoin the cable safely, long term, that are low profile, as in under 20mm if possible?

Honestly, I'd just call in the pros and suck it up. You don't want to leave that little booby trap for the next owner.

 

[User1234567890]

Lucky boy! A few years back I was adding sockets to a ring main. I'd left the radio on as a reminder that the power was on. My brain somehow reversed this message and as I was signing along to Dio, I happily cut through the cable. There was a loud bang and I shook violently for about 2 seconds before the cable and cutters jumped out of my hand.
You only get away with it once!

Indeed mate, it jolted me backwards and that made me drop the knife. Glad it didn't stick in my foot. I will be more careful in future.

 

[User1234567890]

Honestly, I'd just call in the pros and suck it up. You don't want to leave that little booby trap for the next owner.

I may just do that. I am going to have a look and see what the damage is tomorrow, and make it safe, and go from there.

 

[turpis]

What's it for I wonder, doorbell? Outdoor light?

Any recommendations for a flat as possible junction box, or other ways to rejoin the cable safely, long term, that are low profile, as in under 20mm if possible?

For joints within plaster I believe heatshrinked crimps are a regs-compliant solution.

I'd left the radio on as a reminder that the power was on. My brain somehow reversed this message and as I was singing along to Dio, I happily cut through the cable.

I was rewiring a bedroom just last week. Turned the breaker for the ring main off, put it my earphones and got to work clearing out the old cable. Quickly went into autopilot and ended up taking the cover off an old JB for the LIGHTING CIRCUIT and TOUCHING THE LIVE WITH A METAL SCREWDRIVER!! Felt it right up one arm and down the other. Not nice. No withdrawal reflex though - I guess that's what makes it so dangerous. Was even more miffed that the RCD didn't trip, so assume the current was below the threshold.

 

[User1234567890]

What's it for I wonder, doorbell? Outdoor light?


For joints within plaster I believe heatshrinked crimps are a regs-compliant solution.


I was rewiring a bedroom just last week. Turned the breaker for the ring main off, put it my earphones and got to work clearing out the old cable. Quickly went into autopilot and ended up taking the cover off an old JB for the LIGHTING CIRCUIT and TOUCHING THE LIVE WITH A METAL SCREWDRIVER!! Felt it right up one arm and down the other. Not nice. No withdrawal reflex though - I guess that's what makes it so dangerous. Was even more miffed that the RCD didn't trip, so assume the current was below the threshold.

It's for the outside light. Whoever installed it, put the back box on the blocks and then removed some mortar and pushed in the cable below the surface, mortared over the top, then to the doorframe and upwards, wedged in, mortared over again and hidden. If you look at the back box from the front, the wiring appears to go directly out of the back of it and away, but it goes to the right.

And yep, it's like everything in you malfunctions at once. I'm just glad I wasn't stuck there.

 

[blup]

I got a belt from a 2.5mm ring main which created more of a literal shock than lasting physical damage. Wearing rubber sole shoes on a concrete floor must have helped resistance wise.

Try crimping the conductors and then adding heat shrink

 

[endecotp]

So you’re going to replace it with a cable going by an acceptable route, right?

 

[User1234567890]

So you’re going to replace it with a cable going by an acceptable route, right?

I'm going to have a look at it this afternoon. It doesn't look like I can get to most of it without taking the front door out, and if that is the case, then I think I might have to use an MF junction box splice them together. Will need to chop a bit of block out to recess the box so the plasterboard goes on. Will see what it looks like later. Cheers.

 

[endecotp]

. It doesn't look like I can get to most of it without taking the front door out,

You don’t have to remove all of the old wire, just make sure it is disconnected at both ends.

 

[opps]

Lucky boy! A few years back I was adding sockets to a ring main. I'd left the radio on as a reminder that the power was on. My brain somehow reversed this message and as I was singing along to Dio, I happily cut through the cable. There was a loud bang and I shook violently for about 2 seconds before the cable and cutters jumped out of my hand.
You only get away with it once!

I have had loads of shocks. 2 seconds sounds like a long time.

Fortunately, AC normally results in the muscles relaxing, meaning that you tend to drop whatever you were holding.

I recall my step brother telling about his time as a lift engineer. He opened the external doors on the third floor- the lift was stuck in between floors. He touched one of the cables that loop down from the underside. He then discovered that the insulation had worn away. The DC current resulted in his hand locking on the cable. He couldn't accurately recall how long he was clamped for.

In some respects he thinks it was fortuitous that it was DC and not AC. The AC shock might have resulted in his falling down the shaft. The only (short lived) evidence of the incident was a slight burn on his wrist from the metal battery cover on the underside of his Swatch watch.