Slight damage to SWA cable

Kibo_769 · Mar 25, 2022

Hi,

I've been digging and have nicked the outer sheathing of a 2.5mm SWA cable.
The protection and conductors are intact.

Would it please be possible to advise on how I can repair the outer sheathing by using heat shrink or any other suitable bonding agent to ensure no moisture flows in over time?

I will run an insulation resistance check before and after the repair.

Thanks
Kibz

littlespark · Mar 25, 2022

If you’re absolutely sure there’s no damage to the inner cores, or the breaks in the armour strands, then wrap self-amalgamating tape around it.
It’s more waterproof than insulating tape.

For something that looks more professional… get an underground torpedo joint….
Don’t make a joint, but encase the damaged section within the torpedo and fill with resin as normal.

Have you got a photo? Some repairs are more suitable depending on severity of damage.

Kibo_769 · Mar 25, 2022

Hi Littlespark, Thats great thanks for your reply.

Where can I purchase the self-amalgamating tape and the torpedo joint kit from?
Attached are the pictures let me know what you think?

westward10 · Mar 25, 2022

I have never seen a swa cable with red bedding below the armour so I can only assume the bedding is also damaged and that red is conductor insulation. You are going to need professional help.

littlespark · Mar 25, 2022

I hope that’s not a concentric, with the red core showing.
Could be a DNO job.

Slightly more mangled than I thought at first… a little bit of tape isn’t going to help.

Did you not see the yellow warning tape?

westward10 · Mar 25, 2022

littlespark said:
I hope that’s not a concentric, with the red core showing.
Could be a DNO job.

Slightly more mangled than I thought at first… a little bit of tape isn’t going to help.

Did you not see the yellow warning tape?

Think you may well be correct there.

7029 dave · Mar 25, 2022

Looks like concentric dont it.

littlespark · Mar 25, 2022

westward10 said:
Think you may well be correct there.

I’m not sure… certainly looks like a concentric, but the strands would be black??

Not entirely sure about that…

westward10 · Mar 25, 2022

littlespark said:
I’m not sure… certainly looks like a concentric, but the strands would be black??

Not entirely sure about that…

No I suspect you are correct mind you I can only find Chinese produced cables.

Aluminum Conductor Concentric Cable 600V / 1000V Wrap On Insulation Or Inner Sheath

Quality Concentric Cable manufacturers & exporter - buy Aluminum Conductor Concentric Cable 600V / 1000V Wrap On Insulation Or Inner Sheath from China manufacturer.

www.yifang-cable.com

Vortigern · Mar 25, 2022

What depth was/is that cable at?

7029 dave · Mar 25, 2022

littlespark said:
I’m not sure… certainly looks like a concentric, but the strands would be black??

Not entirely sure about that…

I have seen red strands.

littlespark · Mar 25, 2022

7029 dave said:
I have seen red strands.

Red strands as the outer wires??

I thought red inner, black stranded then bare stranded…. Or split concentric with red inner, then black and some green on the outer

timhoward · Mar 25, 2022

I thought the same but I'm swayed by fact he knows it's 2.5mm and says he can IR it, suggesting he has control of both ends of it.
The current IR results would be a good start.

7029 dave · Mar 25, 2022

littlespark said:
Red strands as the outer wires??

I thought red inner, black stranded then bare stranded…. Or split concentric with red inner, then black and some green on the outer

Definitely seen blue strands brown solid core, sure I've seen red strands got me thinking now maybe not.?

7029 dave · Mar 25, 2022

Tried zooming in could be red conductor, good old 2 core SWA.

littlespark · Mar 25, 2022

It doesn’t look like like 2.5….

It needs professional repair, whatever it is.

If the OP could clarify when it gets looked at

westward10 · Mar 25, 2022

Do we think the word 'slight' is underestimating things.

DPG · Mar 25, 2022

westward10 said:
Do we think the word 'slight' is underestimating things.

Just a flesh wound.

7029 dave · Mar 25, 2022

Yeah bit more than a nick more like a gash.

Kibo_769 · Mar 25, 2022

Hi All,

Thanks for all the comments. The cable was meant to be buried at 600mm but the person who laid in in that particular section skimped out at laid it at less than 300mm and the warning tape wasn't event 150mm above the SWA cable.

This cable has not yet been connected or energised so was able to check the ident. It is a 2.5mm SWA cable and was able to cut a small piece from the slack end. After the repair I will ensure the cable is installed to 600mm depth.

The pictures will illustrate the black sheath, the armour strands. You then have a red insulation inner sheath and then the individual 3 conductors Black, Grey & Brown).

This cable will be used for lighting only and the 2.5mm cable was chosen due to the long run of cable taking voltage drop into consideration.

Please let me know if the repair is still feasible?

Thank you all for your replies

pc1966 · Mar 25, 2022

A repair is always possible, but depending on how damaged it is in the segment it might need two joints and a new small section inserted.

But I would start by cutting mid-damage and seeing if it looks clean enough that it can simply be joined in a suitable torpedo style of resin joint. Something like this:

S6 1.5-10mm Straight Resin Joint Kit for Cables up to 10mm 2 Core

Proven underground cable jointing system

www.cef.co.uk

As the cable has not been installed yet you can easily do an IR test (having checked the far end is clear of any shorts, etc) to get an idea if it is OK even before you start cutting (which you should not do until you are ready with a joint to finish it).

Edit: I would try and simply part the cores, etc, without cutting through, it is best if you don't have actual joints and simply use the resin unit to allow it to be inspected and covered over if no real damage is seen.

Mike Johnson · Mar 25, 2022

westward10 said:
Do we think the word 'slight' is underestimating things.

Slightly pregnant comes to mind.

westward10 · Mar 25, 2022

It does have red bedding never seen that before.

Kibo_769 · Mar 25, 2022

littlespark said:
I hope that’s not a concentric, with the red core showing.
Could be a DNO job.

Slightly more mangled than I thought at first… a little bit of tape isn’t going to help.

Did you not see the yellow warning tape?

see y last thread, the inner insulation is red. see the pics. Ill give it a thorough inspection first

timhoward · Mar 25, 2022

As @pc1966 said it's likely you won't have to completely cut it and start again, probably just get a torpedo case around it if IR readings are ok.

They are actually quite easy to use. This video shows the whole process.