radial extension and fuse...

[Simon James]

Quick one:
Can I extend a radial circuit (4mm) with a 13 amp terminal block, with the block behind a blanking plate? If I use 4mm then I assume I will not need an FCU for a spur?

Thanks, any help much appreciated.

 

[ban-all-sheds]

If the fuse/MCB for the radial circuit is 13A or less, you can use a 13A terminal block.

If not, not.

 

[andy]

Quick one:
Can I extend a radial circuit (4mm) with a 13 amp terminal block, with the block behind a blanking plate? If I use 4mm then I assume I will not need an FCU for a spur?

Thanks, any help much appreciated.

yes, but you should be using more than 13A terminal block. why not use a socket instead of blanking plate? on radials, providing you use the same size cable, you can extend it. spurs dont exist on radials

 

[Simon James]

Thanks all.
Yes, of cousrse I could put a socket in! Didn't think of that. Then run off two "spurs" from there.
The problem is that the original wire from the radial is VERY short so need to use the back box space to extend it with a terminal block, thus the need for the blanking plate.
I am assuming the original cable is 4mm, it doesn't look much smaller than the 2.5 mm. Is there an obviously noticable difference?

Hers's a pic....

Cheers SJ

 

[andy]

Thanks all.
Yes, of cousrse I could put a socket in! Didn't think of that. Then run off two "spurs" from there.
The problem is that the original wire from the radial is VERY short so need to use the back box space to extend it with a terminal block, thus the need for the blanking plate.
I am assuming the original cable is 4mm, it doesn't look much smaller than the 2.5 mm. Is there an obviously noticable difference?

Cheers SJ

newer cable is stranded for 4mm and above - 2.5 is solid. but be aware that older cables were stranded for 2.5 (old imperial cable)

 

[Simon James]

Thanks Andy, then that looks like imperial 2.5 stranded?

PS: In my original post/query i missed typed and of course meant to say 30 AMP TERMINAL BLOCK, NOT 13!

 

[ban-all-sheds]

It is an old imperial size cable, but it does look fatter than the approx 2.5mm² equivalent.

Both those holes in the back-box should have grommets in them, BTW...

 

[andy]

Thanks Andy, then that looks like imperial 2.5 stranded?

hard to tell what size it is. go to CU, switch power off, open up and see how many cables leave the fuse for that circuit. and what size is the fuse? if 2 cbles leave fuse, use multimeter to see if they are part of a ring or not

 

[Simon James]

BAS- Will put grommets on I promise!
Thats gonna need be a fused then if the cable is different size?

 

[andy]

BAS- Will put grommets on I promise!
Thats gonna need be a fused then if the cable is different size?

depends. if it goes to another socket first, then that socket will have to be the FCU

 

[Simon James]

Andy- 32amp fuse in CU, two wires leave fuse, not part of a ring...

earlier you said that 'spurs do not exist on radials' so why would I need an FCU here? Am I not just extending the radial on to an extra socket outlet? (assuming cable IS the same size)

SJ

 

[ban-all-sheds]

Two radials then, in approx 4mm². If you don't use 4mm² to extend, you should fuse down with an FCU.

 

[plugwash]

i presume by not part of a ring you mean that you tested for ring continuity and didn't find any.

if it is indeed 2.5mm or something close to that it sounds like it was originally a ring but it got split later (kitchen fitters seem the usual suspects for doing this).

 

[Simon James]

No, not a split ring ( ). I think BAS is right, two radials, the other is an old socket in the living room.
That would make the cable 4mm. (house built 1959) So I think I need to fuse down.
The main problem is the damn short wire....just need to extend it then I could go straight to an FCU..
SO: Can I join that 4mm cable with a 30 amp terminal block, behind a blanking plate..?

Thanks all.

 

[plugwash]

yeah joining it with 30A terminal block is fine.