Underground/buried connection

[jumpjamesjump]

Hello all
I have been called out to quote for a garden job where the builder has run a 6mm armoured cable out to the garden, it's not long enough for it's final destination though and so I want to connect onto it, extend it and bury it. Never having buried an outside joint before what is a good product for the job? I see there are a variety of epoxy resin options but I can't seem to find one that I can easily maintain the armour's continuity.

Any suggestions much appreciated

 

[Andy78]

Every resin cast joint I have ever done has come with braided earthing strap and constant pressure springs to link across the armourings.

 

[Taylortwocities]

The epoxy joints contain a strap to maintain the continuity of the steel armour.
Alternatively, you could use one of these

 

[123]

Every resin cast joint I have ever done has come with braided earthing strap and constant pressure springs to link across the armourings.

Last few torpedo's resin joints I've had have had a jubilee clip and a metal ring (olive?) and braided earthing strap, and either choc blocs or through crimps. Still find the idea of using the choc blocs worrying so I'd use Wago's instead.

 

[pirate]

never underestimate the value of a jubileel clip!
It is your friend in many circumstances!
However, i wouldn't advocate them as ideal for cpc continuity cos i would get slagged off endlessly!
They also make novel napkin rings and can be used as an aid to premature....no, forget that...I'll get my coat!

 

[suffolkspark]

Did one last week on 6mm 2core swa, builder had stuck the digger through it, it came with those constant force springs and strap, but I also kept a few strands of the armour long from each side and put in a couple of connectors aswell (kit came with 4)

 

[radiohead]

I don't trust those spring/braid thingies. On small SWA's like the OP's 6.0mm I leave the steel long and join ALL the strands either in a 60a connector or a line tap. I don't trust Pratley boxes either. Had to dig up quite a few over the years where water has got in. Resin joints done correctly will never fail.

 

[suffolkspark]

Also had to dig up a couple of pratley boxes in the past, if the paint is damaged on them the metal below oxidises and goes white, have this where the seal is and water can leech in

 

[Midwest]

I don't like burying joints. Is there not scope to make the joint accessible for the future?

 

[pc1966]

The Birkett ones seem to get good thing said about them:

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

Proven underground cable jointing system

www.cef.co.uk

They have the constant-force springs for CPC continuity (as mentioned by Andy78) and once filled with resin ought to be as good a seal as you can get. But I would read the instructions twice and follow them carefully!
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At least at this time of year you ought not to have any issues with the mixing / viscosity / curing of the resin filler.

 

[Taylortwocities]

One thing that I don't get with these, and I've used a few....,

Regs say that screw terminations should remain accessible. Most of these kits use screw terminal connectors and are certainly not accessible, being encased in resin and buried half a metre down!

 

[pc1966]

Regs say that screw terminations should remain accessible. Most of these kits use screw terminal connectors and are certainly not accessible, being encased in resin and buried half a metre down!

Yes, but screws encased in resin can't unscrew with thermal cycling or vibration!

Sort of Threadlock with extreme prejudice!

 

[Andy78]

One thing that I don't get with these, and I've used a few....,

Regs say that screw terminations should remain accessible. Most of these kits use screw terminal connectors and are certainly not accessible, being encased in resin and buried half a metre down!

As far as I know the regs don't make any specific mention of screw connections being accessible. In fact 526.3 points out that a joint designed for burial need not be accessible.
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I don't trust those spring/braid thingies. On small SWA's like the OP's 6.0mm I leave the steel long and join ALL the strands either in a 60a connector or a line tap. I don't trust Pratley boxes either. Had to dig up quite a few over the years where water has got in. Resin joints done correctly will never fail.

I know what you mean about the earthing springs. I have always wrapped them tight then tightly covered over with SA tape in the direction of spring coil to hold them fast while the resin is poured. Once the resin is in and set I have no worries about the connection.

 

[DefyG]

I can't seem to find one that I can easily maintain the armour's continuity.

Never known one not to include earth continuity strap, clamp or constant tension springs!

 

[ipf]

Yes, but screws encased in resin can't unscrew with thermal cycling or vibration!

Sort of Threadlock with extreme prejudice!

….ideal for chucking under floorboards, them sub joints.