How to joint?

[OxiaUK]

This is only for info as its something ive wanted to know for a while.

if you have a 10mm cable and you want to joint it (for example maintenance free) how would you do this?

most connectors only go up to 6mm..

and to make it more fun, how would you join a 10mm to a 6mm if you ever needed to and again make it maintenance free?

Thanks

 

[EFLImpudence]

Plenty of large junction boxes but not sure any are MF.

 

[OxiaUK]

Plenty of large junction boxes but not sure any are MF.

Thats my point... i dont see how your supposed to do it if you REALLY needed to and keep in safe and to regs.

 

[flameport]

These: https://www.tlc-direct.co.uk/Products/BHCRIMP10.html
a decent crimp tool (preferably hydraulic) and heatshrink to cover them

 

[ericmark]

I would use a set of these, since I have a set, but to be frank they do not work that well on 10 mm² when I wanted to extend cables I did buy a set for 10 and 16 mm which were much smaller and did a better job, there are both shrink sleeve and epoxy resin joint kits.

 

[JohnW2]

Thats my point... i dont see how your supposed to do it if you REALLY needed to and keep in safe and to regs.

As has been said an implied, even if there aren't 'MF' junction boxes available for large cable sizes (**), you still have a choice of crimping (various options available), soldering, brazing etc. all of which (with appropriate insulation) would be compliant with regs.

** I'm not sure about the 'bureaucratic' situation as regards compliance with Standards that would satisfy BS7671, but is it not the case that joints using non-screwed terminals (and hence essentially the same as the 'MF' JBs we know and love) have for a long time been used in industrial (and perhaps even electricity distribution) industries for very large conductors?

Kind Regards, John

 

[bsr]

Resin joints must be MF? How are the cables joined in them? Crimped I assume.

https://www.screwfix.com/p/prysmian-puj10cc-10mm-resin-joint-kit-4-core-max/43363

 

[JohnW2]

Resin joints must be MF?

They would certainly be difficult to 'maintain'

How are the cables joined in them? Crimped I assume.

Yes, I believe so.

Kind Regards, John

 

[ericmark]

Cores normally crimped, the earth often a scroll which presses a braid onto the SWA with a former underneath the SWA to hold it firm. But since the whole thing is filled with epoxy resin even if screw terminals used they can't come loose.

 

[JohnW2]

.... But since the whole thing is filled with epoxy resin even if screw terminals used they can't come loose.

The screws couldn't literally 'come loose' (i.e. rotate in their threads) but the actual electrical connection presumably could - e.g. due to 'creep' (maybe due to thermal cycling) in the material of the conductor(s)?

Kind Regards, John

 

[ericmark]

The screws couldn't literally 'come loose' (i.e. rotate in their threads) but the actual electrical connection presumably could - e.g. due to 'creep' (maybe due to thermal cycling) in the material of the conductor(s)?

Kind Regards, John

But the same can happen in a crimped joint, so there is no difference be it crimped or screwed. In the main a screwed joint will use Alan keys or other method where a set torque which is quite high can be applied. I would agree with the shrink sleeve type really does need to be crimped, but the pour in epoxy resin type, it really does not matter.

 

[JohnW2]

But the same can happen in a crimped joint, so there is no difference be it crimped or screwed.

Are you suggest that we should be allowed to pour resin (or, indeed, just use thread locking fluid) into a standard screw-terminal (non-'MF') JB and then treat it as 'maintenance-free'?

Kind Regards, John

 

[davelx]

Are you suggest that we should be allowed to pour resin (or, indeed, just use thread locking fluid) into a standard screw-terminal (non-'MF') JB and then treat it as 'maintenance-free'?

Kind Regards, John

I think I'd call that "non-maintainable" ☺

 

[JohnW2]

I think I'd call that "non-maintainable" ☺

Indeed ... as I previously said about 'resin joints' in general...

They would certainly be difficult to 'maintain'

Kind Regards, John

 

[OxiaUK]

Thanks for all your replies, some interesting points here. How do you joint say a 10mm cable to a 6mm cable? surely you cant crimp a 6mm cable in to a 10mm uninsulated crimp joint?