Ugh Not my Day :(

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GRRRR.... lol fitting up my new RO unit for my tank. had to drill into a external single skin wall to fit, insanely i actually thought before I drilled well better just see if any cables so looked around and all sockets were miles away and no light fittings near by so ok lets go......



:( had to happen lol. Downstairs lighting circuit.

Now I want to keep the wall flush but I am assuming a junction box here is the only way?
 
Looking at pic, you have snicked both cables.

I would remove plaster complete length of run & replace cable, better than trying to repair with junction box.
You might just get away with damage to right cable to wrap it with insulation tape.

Probably got just enough depth for plastic capping.

Left cable is lighting, what's the right one, looks larger cable?
 
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I am assuming the right is power. Again I think my sparky was charging by the metre this day as it's a false ceiling!!! Why not go up then down :(.

No chance pulling out the cable lol it would mean completely re plastering that wall.
 
Has it broken the wire or just taken off the coating? If the latter is personally be very tempted to wrap it in tape.
 
Well the lighting circuit it has actually gone through and mergerd the 2 cores. However the power ring looks just about 1mm of insulation so that's ok.

Just the damn lighting ring which has shorted.
 
Easiest fix...

Bang the hole out abit more and square it up - say 1 inch each side of cables and 3 inch above/below - to allow space to work and for capping later to plaster / fill over.

Get some red butt crimps - which are maintenance free so can be covered up and strip both damaged ends and see if you have space the get them crimped together - use a proper ratchet crimp tool for the correct pressure / fixing.

If no luck try and tug for slack from both damaged ends - that pic looks like no slack available :( - try to crimp again.

If no luck the cut one end of damaged cable and crimp a new piece of t+e to it and use that to extend the cable enough to crimp into the other damaged end.

Then you can optionally use capping or just carefully plaster / fill over the joint.

Either keep power off until plaster dry or watch out for the wet plaster being live or tripping rcd of that circuits is rcd protected
 
I had this issue going 'round a doorway' when knocking plaster off (nice safezones!).

Reg friendly way of doing it (as will be classed as not accessible) was as above, open up hole, butt crimp with self-amalgamating tape, stagger the joins and then fill over
 
You've probably addressed this by now but the best way to do it (assuming you can't replace the cable run) would be with heatshrink crimps and a layer of heatshrink tubing, then just re-plastering.
You don't really need any capping or trunking on top as the only real purpose they serve is accessibility in the future, that's not your concern.
Simply using & burying a junction box or choc blocks could lead to you digging in to the wall again if the terminals loosen, don't do that.
 
You've probably addressed this by now but the best way to do it (assuming you can't replace the cable run) would be with heatshrink crimps and a layer of heatshrink tubing, then just re-plastering.
You don't really need any capping or trunking on top as the only real purpose they serve is accessibility in the future, that's not your concern.
Simply using & burying a junction box or choc blocks could lead to you digging in to the wall again if the terminals loosen, don't do that.

1+ Heatshrink and crimps is the most sensible route anything that isn't a captive joint and buried will not comply with Regs which if followed in the first place by the person who lashed them cables in wouldn't have been run where they are now.
 
Has it broken the wire or just taken off the coating? If the latter is personally be very tempted to wrap it in tape.

You can clearly see that the copper on either the phase or neutral on the left cable has been nicked and it's CSA compromised.

You need to carefully strip the outer insulation back (make sure it's isolated first :p ) and then visually inspect the CPC and the other cable, provided the actual copper hasn't been damaged then their is no need to cut and re-join them.

Either crimps or terminal blocks when terminated correctly will be electrically sound and safe.
Before plastering over the repair I would do an end-to-end resistance test & 500v insulation test just to confirm the repair is electrically sound.
Easy fix, shouldn't take longer than 5-10mins including testing.
 
There is no regulation to use capping when burying cable it's good practice however even though it gives little or no protection against a drill! It's mainly used to stop the plaster slicing the cable with his trowel when he's spreading. The only way to repair as suggested is with ratchet crimps and heat shrink and tested afterwards. You can't bury screw type terminal blocks into plaster even if it's in a chocbox or similar.
 
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Only real use of capping or some sort of protection in this case it to get power up ASAP, if your not going to heat shrink the joints as it keeps the wet plaster out of the joint, preventing the plaster becoming live or tripping an RCD etc.

Not that unusual to get a poke from wet plaster or have RCD trips if you plaster directly onto/over a joint
 
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