extending ring

[martysparky]

I have to wire a feature wall. basically the wall has been altered and a double pole switch for a potential lift is now inside a new stud wall (New house).

I want to use the feed from the switch that is on the ring main to feed sockets for the TV and media plus some lighting 200w max.
As access would be awkward to the dry lining box I have been considering crimping the ring main and extending it about 10 inches to S/F/C/U to supply the sockets. Then spur of the F/C/U to another F/C/U to supply the 200w down lights.

Sound ok or is there a better way anyone can suggest?

 

[martysparky]

Thanks Rocker I appreciate that but the job done now I done a spur from existing f/c/u inside structure and provided access.

 

[JUD]

true enough. so why do a lot of manufacturers make connectors rated at 32A for a ring when 2.5mm2 cable carries 21A?

just a thought?

2.5mm² can carry 27A (method C) when wired as a radial.

 

[Voltimax]

Heatshrinked crimps should be fine, in my estimation.

Properly crimped crimps are adequate, though.

Sorry, but I disagree, there is another electrical forum on the internet that has a picture of a joint such as you describe with the neutral burned out because it became loose. Stranded cables are fine, but crimps are not well designed to go onto solid cores. Just because a wire has heat shrink it doesn't make the joint any stronger.

 

[martysparky]

Bs 7671 says they are acceptable though...

I took some 1.5 and looped and connected it with crimps via my ratchet crimper and two people playing tug of war could not pull the loop apart. I think they are strong.

Was the pick of a joint that was not executed properly I wonder?

 

[Voltimax]

BS 7671 may very well say they're acceptable and I don't dispute it. All I'm saying is they're not very good on solid cores and as for letting someone play tug of war with it before burying it, not a good idea, they may not have been able to pull them apart, but they may have weakened/loosened the joint. Time will tell on that one as it invariably does. That's the trouble with a loose joint, it doesn't fail right away, it gets hot.

 

[martysparky]

lol. no the loop was just an experiment and was not buried in the wall that would be pointless.

Can't see how the joint would move if clipped or buried.

But, can see that logic with loose inside a dry lining. hence the question.

Most likely 100% of the time I would err towards caution and i will not be using crimps if the cable is left unfixed I would use as Rocker suggested Helecons or Wagos.

 

[Voltimax]

I can see you know what you're doing and are no fool

 

[martysparky]

ok, but is it ok to spur from the ring to supply a FCU 5A fuse, then spur from this to supply another FCU 5A fuse.

Yes, someone could change the fuses and put in 13A so use 4mm cable although 1.5 would be sufficient for the intended load.