Cable to kitchen island

[nozspark]

My brother is having a new kitchen fitted shortly and now wants an island, so I presume that the easiest way of supplying power to it from the kitchen ring is via a switched fused spur & some swa burried in the concrete slab (the chase for the swa will not be very deep and the floor wil be tiled over after).

Any thoughts??

 

[Space cat]

Thought one: If you're going to all that trouble to get power to an island why restrict yourself to 13 amps? If you can get one cable there you can get two. I would extend the ring instead.

Thought two: How deep is the damp proof membrane in that slab?

 

[RF Lighting]

Thought one: If you're going to all that trouble to get power to an island why restrict yourself to 13 amps? If you can get one cable there you can get two.

Or even just one 4 core SWA or MICC

 

[nozspark]

Good idea about extending the ring to the island, I was going to run as a spur

Do not know about the depth of the membrane, so would not want to go too deep (prob about an inch and a half max - then tiled over)

RF - you talking about using 4 core swa, one pair for one leg and other pair for other?? would armour be up to being CPC??

 

[scott6471]

If your going to use a 4mm SWA then why not just a 3core radial?

It's current rating, based on what we've been told, is 34 amps making it a perfect alternative to the ring method (this assumes that the protection is via an MCB/RCBO etc and that there are no other correction factors involved).

Unless i'm missing something, this way you wouldn't have to install a spur at all (just connect to the nearest socket outlet), the other benefit would be that one of the internal cores is then used as the CPC.


Scott

P.S Don't forget that this will need notifying to the local authority

 

[Steve]

scott, it would be a spur! Just not fused! And to the regs you could only have one socket on it, even if it were 16mm²! This is the rule of spurring from ring finals.

 

[davelx]

scott, it would be a spur! Just not fused! And to the regs you could only have one socket on it, even if it were 16mm²! This is the rule of spurring from ring finals.

Only if you want to avoid having to do the full design calcs. Otherwise you can use any circuit configuration you like,

 

[scott6471]

scott, it would be a spur! Just not fused! And to the regs you could only have one socket on it, even if it were 16mm²! This is the rule of spurring from ring finals.

Steve,
I think to what you refer is an item from the on site guide and not directly covered within BS7671 (and i can't see where it mentions "even if it's 16mm").

I think this query is all about sound design (in this case ccc of cables).

We know, from the guide, you can have many points on a spur as long as they are protected at the spur point by a suitably rated FCU. The single only point on a spur refers, as you are aware, to those that are not protected by an FCU and whilst not explicit in its explanation i think assumes that they are also to be wired in the same size cable i.e. 2.5mm (hence the in line FCU on a multi point spur section).

As long as the design is sound i don't see any reason (within the regs) as to why it is unacceptable to have multiple points on a non FCU spur from a ring final circuit.


Scott

 

[plugwash]

spurring too much from one point on the ring could well cause serious ring balance issues if that point is not near the middle of the ring.

 

[plugwash]

Only if you want to avoid having to do the full design calcs. Otherwise you can use any circuit configuration you like,

The key word is full design calcs, that includes stuff that most people never bother to think about like ring balance as well as the usual stuff.