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

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.

Absolute worst case is two joints and a new section, like this one I had to do:

[ElectriciansForums.net] Slight damage to SWA cable

Kibo_769 · Mar 25, 2022

pc1966 said:
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.

Thanks pc1966 - ill clean the muck off remove the damaged outer sheathing and then inspect and use the resin cover without cutting the cables if there is no visible damage. ill post pics once completed

Kibo_769 · Mar 25, 2022

littlespark said:
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.

Thanks littlespark - ill clean the muck off remove the damaged outer sheathing and then inspect and use the resin cover without cutting the cables if there is no visible damage

catdog1121 · Mar 25, 2022

When he said nicked the outer sheath. i was thinking a small cut and was going to say just wrap a load of electrical tape or heat shrink to protect the SWA from getting rusty.. I guess this highlights the problem with forums, one persons nicked it with a spade is another persons mashed it with a spade..

Kibo_769 · Mar 25, 2022

timhoward said:
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.

Absolute worst case is two joints and a new section, like this one I had to do:

View attachment 96365

Thanks Tim - thats is really useful. ill inspect it and send in the results. wher di you purchase the torpedo from? CEF dont have any in stock at the store so will need to order it in

timhoward · Mar 25, 2022

Kibo_769 said:
Thanks Tim - thats is really useful. ill inspect it and send in the results. wher di you purchase the torpedo from? CEF dont have any in stock at the store so will need to order it in

I got it from one of my usual local merchants.
Screwfix sell them, search "resin joint"

Slight damage to SWA cable

Kibo_769

littlespark

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westward10

DPG

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7029 dave

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Kibo_769

Attachments

pc1966

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

Mike Johnson

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westward10

Kibo_769

timhoward

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Kibo_769

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

Kibo_769

catdog1121

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Kibo_769

timhoward

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