4Mm Radial Off Ring Cct

[stuartmcclean]

can a 4mm radial supply sks from a ring cct

 

[Andy™]

no.

 

[SLIPSHOD & SLAPDASH]

can a 4mm radial supply sks from a ring cct

How many ?

 

[binky]

Bit odd, but if on 32A MCB, and installation method is correct, I don't see why not. Biggest problem is getting 4mm cable in back of socket terminals these days. Would be interested to knew why not Andy?

 

[SLIPSHOD & SLAPDASH]

Well i think it could be acceptable. My reasons for doubt are you could be pulling too much current from one leg of the ring & overloading that 2.5 cable. But.......... thats no different to the kitchen appliance grids that are in fashion right now, and why i try not to wire these on a ring but if insisted on, a 4mm radial.

 

[stuartmcclean]

why i am asking is a customer wants a supply for a summer house ajacent to the house , the cu is on the other side and it is not feasable to do it , i explained that a 13amp fused spur would be the answer , however the load will probably be over 13amps not by much but over never the less.

now then can a ring be extended with a 6 core cable or does it have to be seperated by two cables fby regulation

 

[ProDave]

How much over 13A? It takes quite a bit more than 13A to blow a 13A BS1362 fuse

I think the reason a 4mm spur from a ring is not acceptable, is simply that a 2.5mm ring is a special case in BS7671 and the acceptable cable sizes and arangements are clearly defined, and a 4mm spur is not included in the definition.

 

[SLIPSHOD & SLAPDASH]

If you extend the ring then its no problem. Have you done any tests yet. If i remeber correctly in a normal domestic situation 95m aprox is the maximum length you can get away with

 

[SLIPSHOD & SLAPDASH]

Dave, just because its not a standard arrangment it does not rule it out on that reasoning only.

 

[stuartmcclean]

anybody know the answer to the multi core question can it be done within the regs

 

[Steve3948]

Also how far away from the house is the summer house and what is the current earthing arrangement.

 

[stuartmcclean]

tns 32mcb 30ma rcd on cct summer house 3mtrs away

can muli core be used to extend ring

 

[apprentice87]

Hi all,

The regs, and their accompanying diagram make it all perfectly clear...

Unfused spur; "An unfused spur should feed one single or one twin socket-outlet only" Soooo, that is the end of the argument!!

As regards fused spurs, according to the regs and the diagram, they can be used to do a few different things [including fixed equipment], but the killer is, it clearly states " Fused connection unit [FCU] to BS 1363-4" ----- "maximum fuse 13A"

So, that is the end of that then!!!

john...

 

[apprentice87]

P.S. So i suppose it all depends on what is on the end of your 4mm .... You could have a 400mm spur if it only fed one twin socket!!!!

 

[Riggy]

anybody know the answer to the multi core question can it be done within the regs

Can't think of any reg you would be breaking, no different than both legs of a ring down the same conduit.

 

[Riggy]

anybody know the answer to the multi core question can it be done within the regs

 

[batty]

Well I personally would not be to worried about putting three extra sockets say in a bedroom in 4 mm of a ring. In an ideal world you would extend the ring but this may not always be possible. Personally I would not be supplying the summerhouse of the ring. You know for a fact they will want a 3 kw heater in it and probably a lot of other stuff. I would insist it has its own supply and not cut corners. What other stuff is on this ring main?

 

[alpha spark]

Just done a similar thing

However mine was with 6mm swa over 10 m to feed a wooden shed came out of existing socket with 6mm t/e fed a cooker switch swa to cu in she'd and put a Flori and 1 2 gang socket in told him that it wasn't the best but has he'd just had his kitchen done and new wooden flooring put down there was no chance of getting a new feed over until a later date when they upstairs.

I also warned of taking heaters kettles etc to the shed

All test results were fine and just noted on cert y I had to come off existing ring

U know the saying u can only pi*s wi c**k u got

 

[SLIPSHOD & SLAPDASH]

Hi all,

The regs, and their accompanying diagram make it all perfectly clear...

Unfused spur; "An unfused spur should feed one single or one twin socket-outlet only" Soooo, that is the end of the argument!!

As regards fused spurs, according to the regs and the diagram, they can be used to do a few different things [including fixed equipment], but the killer is, it clearly states " Fused connection unit [FCU] to BS 1363-4" ----- "maximum fuse 13A"

So, that is the end of that then!!!

john...

No its not that easy. What reg numbers are you refering to ? Also see post #9 above. Have a look at 433.1.

As i said in #5, pulling too much current off one leg of the ring is my main concern .

Stuart, what is going in the summerhouse thats pulling more than 13A ?

 

[binky]

Hi all,

The regs, and their accompanying diagram make it all perfectly clear...

Unfused spur; "An unfused spur should feed one single or one twin socket-outlet only" Soooo, that is the end of the argument!!

john...

that's for 2.5mm spur off ring not 4mm, so not perfectly clear.

4mm will carry 32A under correct conditions, so I would view this as a 'lollipop' in reverse.