Damaged electrical cables

[Sard]

I've just taken off dot & dab plasterboard from a brick wall as the plasterboard was damaged and cheaper to replace and I've discovered two cables that supply power to a power socket that look they have been cut in to by some sort of tool. The socket has always worked and RCD never tripped. The wires were behind the light switch, which looks like it has been moved previously.

Normally I would have replaced the damaged cables as my circuit is on a ring main and would chased them back to the sockets they loop in and out to but on this occasion, it's impossible for me to chase them back.

Is there anything I can do to repair or replace them mid run?

 

[CBW]

How badly damaged are they and can you provide photographic evidence?

 

[Sard]

 

[Sard]

BTW, I don't mind replacing the cables from any point in the wall, I just can't chase them back to where they originate and then run on to.

 

[chivers67]

Do you know anyone that has an insulation resistance tester? Looks like it's only the outer sheath

 

[Sard]

Do you know anyone that has an insulation resistance tester? Looks like it's only the outer sheath

Unfortunately I don't. Assuming they were damaged and unsafe, what options would I have?

 

[chivers67]

Well the best way would be to replace them along their entire run. You might be able to strip them back and join them both in a maintenance free junction box - is there any slack?

 

[Sard]

Yeah, entire run just isn't possible unfortunately as the area is also under a tiled bathroom. So I have no idea where the cable comes from and goes out to. Can I replace the damaged length and join then using a connector and shrink sleeve wrap? If used a maintenance free junction box, could I still bury it behind plaster?

 

[chivers67]

A maintenance free junction box doesn't have to be accessible.

 

[Sard]

A maintenance free junction box doesn't have to be accessible.

Ah yes of course, so in theory I can cut out some of the block work and place a MF JB in there and then set it in plaster?

 

[EFLImpudence]

You need to find out whether the actual cores are damaged.

 

[chivers67]

yes, just be very careful when your stripping the cable back so you have as much play as possible to work with.

 

[JohnW2]

Do you know anyone that has an insulation resistance tester? Looks like it's only the outer sheath

Unfortunately, IR testing does not prove a lot. For obvious reasons, this work of rodents IRd fine, despite it clearly not being particularly 'safe' ...

Kind Regards, John

 

[Sard]

Unfortunately, IR testing does not prove a lot. For obvious reasons, this work of rodents IRd fine, despite it clearly not being particularly 'safe' ...

View attachment 269789

Kind Regards, John

Yeah, I'm leaning towards a safe repair for my own peace of mind. Any other suggestions to the MF JB approach?

 

[JohnW2]

Yeah, I'm leaning towards a safe repair for my own peace of mind. Any other suggestions to the MF JB approach?

Crimping or soldering plus heatshrink would probably be the electrician's approach (if their preferred approach of replacing the entire cable was 'impractical') but both require skills and/or equipment.

Although it would seem to be 'allowed', I would personally not be comfortable burying an MF JB (in fact, it would presumably have to be two of them) in plaster/whatever.

Kind Regards, John