radial from ring main

[nick611]

So, to all that have posted that it is fine to spur from a 32A, 2.5mm T&E ring final to any number of socket outlets without an FCU beforehand, can you tell me how it is we arrive at the scenario whereby it is fine to protect a cable with a CCC less than that of the associated OCPD, and the fundemental principals that allow us to do this???

lenny you.ve missunderstood.4mm cable has a ccc higher than the ocpd of a 2.5mm ring main.read the thread from the start,and calm down dear

 

[Guest123]

lenny you.ve missunderstood.4mm cable has a ccc higher than the ocpd of a 2.5mm ring main.read the thread from the start,and calm down dear

I have read the thread from the beginning thanks

My point is that you clearly dont understand the fundemental principals of a 2.5mm T&E ring final circuit protected by a 32A OCPD, and the effect 'spurring' off to multiple socket outlets without an FCU beforehand will have on that circuit, frankly that shocks me a little.

 

[nick611]

I have read the thread from the beginning thanks

My point is that you clearly dont understand the fundemental principals of a 2.5mm T&E ring final circuit protected by a 32A OCPD, and the effect 'spurring' off to multiple socket outlets without an FCU beforehand will have on that circuit, frankly that shocks me a little.

even if the spurs are from near to distboard a percentage of current will flow long way round. As 2.5 carrys 80 plus percent of total possible load {32a} i dont think your objections are as well founded as you think they are

 

[chiplard]

hi there, would like your views on this.. Jb off a ring main and run two or three socket,s on a 4mm radial. I myself don,t mind it. no current capacity issues.and no zs problem,s if rcd protected.Any thoughts.

You asked for peoples thoughts, you got them!!!

Seems to me you will do what you want to do anyway, so carry on.

 

[kmcgold]

nick611 has anyone else agreed with you
that you can run 2 or 3 sockets of in a 4mm radial ?

 

[Sav]

Hi everyone,
how about this one then.

outside socket is currently part of a small 2 bed flat ring.

the outside socket has been discarded and an adaptable box has been placed there. From there 4mm swa approx 6 metres into a small summer house feeding 4 sockets and 2 4ft flourescents.

the 4mm swa is made of into a small c/unit and all wiring is in plastic conduit. the small c/unit has a 63a double pole isolator ( no rcd protection as the flat ring that the swa is spured off from is protected by rcd already.

I am carrying out an inspection on this, so would you say this is ok, or not to regs etc.

Thanks for ready and any advise etc would be helpful,
Sav

 

[kmcgold]

i would say no

 

[Sintra]

even if the spurs are from near to distboard a percentage of current will flow long way round. As 2.5 carrys 80 plus percent of total possible load {32a} i dont think your objections are as well founded as you think they are

Have you actually read 433.1.5 and thought about the path of least resistance?

 

[iconnect]

No thats not ok !!! Only if you take the adaptable box out and put a switched fused spur IP Rated with a 13a fuse in. The main switch is not rated to the 4mm and it could carry more than 13a !!!!

 

[Sav]

No thats not ok !!! Only if you take the adaptable box out and put a switched fused spur IP Rated with a 13a fuse in. The main switch is not rated to the 4mm and it could carry more than 13a !!!!

Why not leave the adaptable box where it is !!!!!!! Its big enough to fit a 13a SFCU inside it and its IP65 rated !!!! . Also why the !!!!!, i only asked thats all,
Thanks
Sav

 

[iconnect]

Sorry no offense intended I just always do it lol Sorry. I dont understand why this is still going really its the same as an extention lead you can plug what the hell you like in it as long as it does not go over 13a. The reason is not because of the ring being in balanced but more to protect the cable in the spur as the balance is maintain as it enters the ring in the same place and is no different to pluging in something that pulls 10a hello in balance!
if you spur off the spur without a switched fused spur the only limit is the mcb 32a. The idea is sound without problems no way the spur can take more than 13a s. Am I making sense lol

 

[moosey86]

This topic is very bitchy, I think everyone knows how to do it properly (probably an overstatement there) but I'd imagine most people that take the time to read through a forum like this would want to do it properly.

If your going to take a 4mm up just take two 2.5mm's up, split the ring and then it's done in a proper and recognised way. If I saw that 4mm method done at a job I'd instantly think DIY.

It's pointless getting so ---- about doing it a different way for such a nothing job. And I don't mean that in an offensive way. I'm more talking about peeps that start studying the BRB for reasons why or why not to do it. Let it go people there's more to life than ********.

Hope this helps


Sent from my iPhone using Tapatalk

 

[iconnect]

I agree 100% more to life

 

[Paul.M]

I've just done a search on Google for:- balanced ring main, to find out once and for all what the intelligence of the world wide web had to offer. Guess what came top if the list? My rant on this thread post 42. Just goes to show that you can't believe everything on the internet.

 

[KFH]

On the issue of the unbalanced ring. Assume 3 X 3KW fires connected on unfused spur (I have seen it done in one room in order to dry plaster/paint) assume that the spur is connected 1/5 of the way around the ring and there is no other load on the ring.

9KW = 39A which will not trip a 32A MCB in a hurry. 1/5 of 39A will go the long way around (7.8A) and 4/5 will go the short way (31.2A) this is in excess of the 23 A for 2.5T&E installed to method B.

I will leave it to others to do the calcs on how long before the 2.5 T&E gets a bit hot and to access whether the scenario is reasonable. A load of 28.75A would not overload the short leg of the ring in the above scenario (23A = 4/5 of 28.75)

 

[jaresquire]

Kinda wish this thread would die but....
If you extended the ring at the same point as the spur the current in each existing leg would be?

 

[KFH]

Jaresquire,
The load on the short leg of the extended would be the same as my example, an unbalanced overloaded segment of the ring. Which is what I suspect your question implied.

A good reason not to have rings, the users do not know/care about unbalanced loads. After all it has been properly installed, how can they overload it without a fuse/breaker tripping, they will ask when their house has burnt down. Having said that how many fires have been caused by an overloaded ring never mind an overloaded segment? Stats appear to show very few if any.

As someone said before why all this fuss about something we would not install? But I am one of the guilty parties by continuing to post:-(

 

[jaresquire]

Yeah I think this is just a regs issue and as I posted earlier best just to avoid such a spur but I would only do an advisory if I came upon it.

 

[marky sparky]

yes ! but they were talking about radials from ring main and not other configs

 

[bennett3291]

regs state u r only allowed to spur off the ringmain with one double skt or 2 single skts at anyone point.

 

[con-site guide]

As long as JB accessable there is no problems.

 

[kmcgold]

only one single or double socket etc

 

[j.mawer]

And so the cycle begins again!

 

[Adam W]

Reasons you shouldn't:

1. It is prohibited by 434.2.1 - "The part of the conductor between the point of reduction of cross-sectional area or other change and the position of the protective device shall not exceed 3m in length..."
2. It is prohibited by Appendix 15 - "An unfused spur should feed one single or one twin socket-outlet only..."
3. It is unprofessional - ingenious little 'solutions' like this are the hallmark of the DIYer.
4. It's easy enough to do it properly, ie in accordance with the regs.
5. It creates unnecessary confusion for someone unfamiliar with the installation - the spur appears to be an A2 radial but leaves the consumer unit as an A1 ring.This could even be dangerous when it comes to isolation.

Reasons you should:

Apparently it's easier to take 1 cable up to the loft, although it's easier to get 2x2.5mm cables into the terminals than 2x4mm.

... And that still doesn't explain why you can't fuse it down, like an extension lead.

 

[kmcgold]

Reasons you shouldn't:

1. It is prohibited by 434.2.1 - "The part of the conductor between the point of reduction of cross-sectional area or other change and the position of the protective device shall not exceed 3m in length..."
2. It is prohibited by Appendix 15 - "An unfused spur should feed one single or one twin socket-outlet only..."
3. It is unprofessional - ingenious little 'solutions' like this are the hallmark of the DIYer.
4. It's easy enough to do it properly, ie in accordance with the regs.
5. It creates unnecessary confusion for someone unfamiliar with the installation - the spur appears to be an A2 radial but leaves the consumer unit as an A1 ring.This could even be dangerous when it comes to isolation.

Reasons you should:

Apparently it's easier to take 1 cable up to the loft, although it's easier to get 2x2.5mm cables into the terminals than 2x4mm.

... And that still doesn't explain why you can't fuse it down, like an extension lead.

The end........

 

[Soulsurfer]

5 years on and I've just had this exact same argument with a company today, rough as ffff ! even tried arguing the point !

 

[Soulsurfer]

So went to help out a new company as a subby today possibly for more too as electrician they had onboard was keen on drink ;-) lots of it stashed on site etc..
They have a 1st yr apprentice left there trying to basically learn to fit new kitchen wiring and bathrooms with no knowledge at all basically and while elderly people are still living in the flats high rise.

I start looking to fit new socket faces and general 2nd fix and test today and find back boxes all steaming etc.. and the tiler has tiled at 55 degree angles to the boxes that were already on the lash ! then I get to asking him- apprentice why they have run spurs off spurs off spurs from original ring all in 4mm twin no less at a guess to carry the current as opposed to 2.5 and extending the ring final, and they have in a few flats looped 4mm twins in and out and picked up DP switches to isolate sockets in alcoves etc.. for washing machines and the like then added as I say spur after spur essentially making one point of the entire flat ring circuit into a radial.

Then at one end they have fed 4mm into a single box to feed a switch for an extract fan up above and come straight off in 1.0mm twin ! I said why not into a SFCU to enable fusing it down at least but he said two sparks said it was all good ?? well he said one said he wouldn't do it like that but it was ok !

Next flat even better same issue mainly spur off ring and then as a radial to 6 plus sockets or DP switches and on to sockets after, then I ask where is feed from ring in ? Young lad says oh it's there other side of kitchen ! So I look and no they have a cupboard with a big slack heap of 4mm bundled in there, then he says oh yeah there's a feed the other side to opposite work top and units too, no linking cables up and over etc.. just the single 4mm one side spurred off the ring and other side of kitchen everything is linked together and waiting to be fed separately from the 4mm bundled in a hall cupboard ! So by now I'm thinking someone has a big hat and horse outside, and so in for a penny I ask him where the previous spark had said he was taking the 4mm ? and he says just in the back of that single socket in the hallway to feed the kitchen as a spur !!

Where do these people come from and how can they sleep at night !
Am I just being picky or is it utter shi*e ??

 

[Hellmooth]

My god that isn't an easy read lol

 

[Hellmooth]

Did you stop for breath there at all?

 

[Pete999]

hi there, would like your views on this.. Jb off a ring main and run two or three socket,s on a 4mm radial. I myself don,t mind it. no current capacity issues.and no zs problem,s if rcd protected.Any thoughts.

I would suggest you read, inwardly digest Appendix 15 of the BS 7671, which give you all the details of Ring final circuits and Radial final circuits, what you are suggesting smacks of " you don't know what you are doing" sorry for being blunt but this is basic stuff for even a DI

 

[Soulsurfer]

Did you stop for breath there at all?

Ha ha I did but was pretty wound up when I got in from getting interrogated by the muppets that are doing this rubbish work ! Bit hard to explain while off the top of my head but it is garbage and as Pete has posted below to the OP on this older thread, surely by reading Appendice 15 even a layman or apprentice would understand basic ring finals and radials ! lol

 

[valleybilly]

1. 
   Reasons you shouldn't:
   1. It is prohibited by 434.2.1 - "The part of the conductor between the point of reduction of cross-sectional area or other change and the position of the protective device shall not exceed 3m in length..."
2. 4mm clipped direct 36 amps . he is increasing not reducing the csa. Still a stupid idea thou lol.

 

[Soulsurfer]

1. 
   Reasons you shouldn't:
   1. It is prohibited by 434.2.1 - "The part of the conductor between the point of reduction of cross-sectional area or other change and the position of the protective device shall not exceed 3m in length..."
2. 4mm clipped direct 36 amps . he is increasing not reducing the csa. Still a stupid idea thou lol.

Agreed Billy, although just had main contractor on phone texting asking me wtf is going on and why I'm not happy with it ? I said basically it's rough and bad practice and in extreme could overload one or more legs of essentially now a mixed circuit between ring and radial, also a pain for next electrician who comes into place and scratches his head plus ring system now flawed by the endless spur off spur carry on. He's telling me that a BS number isn't going to cut it with him etc.. I said I'll be the one doing the cutting in cutting ties with his gang ! lol

 

[sparkdog]

I thought it was a yellow book, or is that the AA?

 

[Chr!s]

hi there, would like your views on this.. Jb off a ring main and run two or three socket,s on a 4mm radial. I myself don,t mind it. no current capacity issues.and no zs problem,s if rcd protected.Any thoughts.

Hi, there is no technical issue with this other than load distribution.