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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Electrical Questions >> Strange Ring Extension https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1083576748 Message started by PoorOldWil on May 3^rd, 2004, 10:32am

Title: Strange Ring Extension
Post by PoorOldWil on May 3^rd, 2004, 10:32am

Hi folks,

I recently lifted some floorboards in a bedroom, to reveal the tangle of cables and 'floating' JBs that
make up my fixed wiring. My house has a kitchen extension, and the power ring circuit for this seems to
come from one of these JBs, as two 2.5mm2 cables. This JB is connected to a second JB, on one of the main rings,
by a length of heavier cable ( 4mm2 or 6mm2, not sure). So it looks as though the entire ring circuit for the kitchen is
wired as a spur from the main ring. I have never seen this method of extending a ring described in books - does it
comply with the Regs?? The kitchen ring powers 5 x 13A sockets, a FCU to a dishwasher, a FCU to a 1kW water heater and
a FCU to a 150W towel rail heater: so I guess the 4/6mm2 cable is not overloaded (it's been like that for years!).
BTW I checked that the circuit is a ring, not a 'tree' spur.

Never look under the floorboards - there are things there that mere mortals should not see!!

Wil

Title: Re: Strange Ring Extension
Post by HandyMac on May 3^rd, 2004, 10:42am

This does not sound as though it complies with the regs at all.

Are the connections between these bits of wire made with terminal blocks? If so, instantly outside the regs because termination blocks should only be used in accessible locations (and I don't view under the upstairs floorboards as being accessible).

Also, a spur should be just that - one radial t&e to a fused spur. Not an entire circuit like what it seems you have in there.

You home insurance company might not be pleased to have a claim against them in the event of a fire, so now that you are aware there could be a problem you need to get this fixed.

Andrew

Title: Re: Strange Ring Extension
Post by plugwash on May 3^rd, 2004, 11:30am

regs require junction boxes to be accessible though in reality they very rarely are

if possible remove the jucntion boxes completely and replace all cables comeing out from the pair of junction boxes with 2 new cables to give one continous ring with no junction boxes

failing that remove one cable from the main ring to the pair of junctino boxes and one cable from the mini ring to the pair of junction boxes and run a new cable between theese sockets to give a proper ring but with the junction boxes left in

failing that remove one cable from each or the pair of junction boxxes and join them with mroe junction boxes and cable but i really wouldn't wan't to introduce so many junction boxes

Title: Re: Strange Ring Extension
Post by L.Spark on May 4^th, 2004, 1:31am

and failing that!, get a spark in to do it mate, you could risk electricution quite easily handling this yourself, especialy with JB everywhere! - up to you! :-/

Title: Re: Strange Ring Extension
Post by PoorOldWil on May 4^th, 2004, 8:45am

Thanks to all for your advice - looks like I have some re-cabling to do! By repositioning a couple of sockets, I can complete the ring using two sets of connections, which I can put above the floor so that they are accessible.

I lifted a few more boards and found other horrors - the 6mm2 feed to the kitchen hob/oven comes up through the ceiling from the CU below, straight into a JB then on to a second JB where it connects to new cable to the kitchen extension. The force needed to cram two 6mm2 cables into the first JB has broken the box - large bits of plastic left there - and the broken JB 'floating' by the cables :o. No option here but to re-cable back to the CU!

The extension was done by a reputable (?) local builder, but I think the electrics must have been done by the brickie's labourer in his tea-break!

Title: Re: Strange Ring Extension
Post by HandyMac on May 4^th, 2004, 12:51pm

wrote on May 4^th, 2004, 8:45am:

If ya crimp the cable joins then ya can bury them. It's only choccy blocks that have to be accessible.

Andrew

Title: Re: Strange Ring Extension
Post by L.Spark on May 4^th, 2004, 2:04pm

well if it's (the crimps) not contained in anything, at minimum tape them all up, i would put in a chocbox regardless tho, JB's arent exactly accesible under the floor are they? so why should chocboxes be? not that im saying its best, but having things accesible just doesnt happen! ::)

Title: Re: Strange Ring Extension
Post by HandyMac on May 4^th, 2004, 4:23pm

wrote on May 4^th, 2004, 2:04pm:

I'll be happy to bow to your greater authority on the subject if need be, but my understanding was that choccy blocks were not allowed if they aren't accessible. Whereas crimped connections can be buried.

I agree 100% that the crimps should be taped, or perhaps even better put in JBs. Tape can be a pain in the arse to get undone again in future should that joint ever need to be exposed.

Stanley knives at the ready chaps! ;)

Andrew

Title: Re: Strange Ring Extension
Post by plugwash on May 4^th, 2004, 6:23pm

most types of connection are supposed to be accessible however junction boxes rarely are

the things that don't need to be accessible include (there may be others)

crimped joints
soldered joins
resin encapsuated joints

Title: Re: Strange Ring Extension
Post by mart_the_spark on May 4^th, 2004, 6:24pm

bit worrying, 'perhaps in jb'.....

Surly if you are gonna use through crimps you gona but them in a gewiss box or similar arnt you??

And tape?? Heat shrink sleeve would be your best bed for the non insulated types.

Title: Re: Strange Ring Extension
Post by PoorOldWil on May 4^th, 2004, 6:56pm

Some useful ideas on connections..not too sure about crimps, as I'll be using single-conductor t+e cable: I think
crimps are best with stranded-core cables. Having sorted out the various JBs that litter the underfloor space,
I have to re-position and reconnect one 3core+cpc lighting circuit; two 2.5mm2 t+e for the kitchen ring; one 6mm2 t+e
for the kitchen oven/hob and one 6mm2 t+e feed to the garage. As the room above the floor is being converted to an
en-suite bathroom (which is why I lifted the boards in the first place!), I'm a bit limited in where I can put the
connections: they will have to go in a closed compartment which houses the shower pump. No doubt the pump will
blow its pushfit connectors at the first opportunity, so I'll make all the connections in a IP66 box,
using 35A DIN terminals on a rail.

Wil

Title: Re: Strange Ring Extension
Post by plugwash on May 4^th, 2004, 7:15pm

any box with more than one cuircuit entering should be clearly labled as such

Title: Re: Strange Ring Extension
Post by mart_the_spark on May 4^th, 2004, 7:19pm

"isolate from multiple sources"

Title: Re: Strange Ring Extension
Post by L.Spark on May 5^th, 2004, 1:50am

Andrew, the problem is there is no real protection when you just have crimped and taped connections, and JB's would technicaly need to be accesable, but they often are not. putting them in a chocbox or a jb is just doing the same required thing.

Title: Re: Strange Ring Extension
Post by L.Spark on May 5^th, 2004, 1:52am

wrote on May 4^th, 2004, 7:19pm:

"isolate from multiple sources"

'isolate elsewhere' still not recommended!! :o

Title: Re: Strange Ring Extension
Post by HandyMac on May 5^th, 2004, 6:51am

wrote on May 5^th, 2004, 1:50am:

Andrew, the problem is there is no real protection when you just have crimped and taped connections

Understood.

However if the crimped connections were made in the void under the 1st floor then presumably you could leave the crimpe unprotected anyway?

Andrew

Title: Re: Strange Ring Extension
Post by rabbit_rabbit on May 5^th, 2004, 7:01am

ALL connections MUST be within an enclosure - and regardless of voltage SELV as well. So if ya crimp or use terminal strips they MUST be enclosed - ya can get those small plastic boxes (ChocBoxes) from most vendors even SF do them! And the lids snap on and also come with screws to screw down so complies with "need for a tool" bit as well as cable clamps - quite a neat job really.

RR

Title: Re: Strange Ring Extension
Post by HandyMac on May 5^th, 2004, 7:20am

wrote on May 5^th, 2004, 7:01am:

I just learnt something - thanks!

Andrew

Title: Re: Strange Ring Extension
Post by L.Spark on May 6^th, 2004, 12:56pm

yep thanks for just claryfying that Ray, that was what i understood of connections.