Ring wired in 2.5mm and 4mm

[kingeri]

Being trying to sort out the sockets at a house this morning. A right mess, spurs off spurs everywhere. I have identified the ring itself and how it runs, but it seems it is partly wired in 2.5mm and partly in 4mm, seemingly at random. I know it's electrically sound, tested it and it's fine, but it just annoys me, even at the CU there is one of each size going into the breaker. Why?????

 

[malcolmsanford]

What was available on the van?

Mate from the local leccy people could only get some of each for nothing

 

[Ohm4]

Maybe the guy who did it just used what he had available? couldn't afford new cable? who knows!

It would annoy the hell out of me though! I'd be ripping it out! :wink5:

 

[Geoffsd]

Thermal insulation ?

 

[kingeri]

No thermal insulation. I'd like to re-run a new 2.5mm ring but as the current install is safe and, although annoying, mixed conductor sizes isn't reason enough alone to justify recommending a rewire in my view. It's not contravening any regs that I know of! Just poor practice.

It looks to me like it was originally a 4mm radial (red and black T&E), and someone has at some point turned it into a ring using 2.5mm (brown/blue).

 

[DPG]

Why would you want to charge the customer for downgrading his wiring? Daz

 

[MDJ]

Definately a case of the spark ran out of cable and thought rollocks to it some 4mm2 cable will do to finish it off, thats what I suspect anyhow.

 

[Engineer54]

Are you sure the 4mm cable IS 4mm and not the imperial 7/029-7/036?/ That may make a lot more sense!! lol!!! Maybe that in the not too distant past a fault occured on one leg of this ring and got replaced with 2.5mm!!

The dead give away here, would be the cables CPC in imperial cable it will be multi strand 3/029, whereas on a 4mm it will be a solid core....

 

[Ohm4]

I wouldn't charge a customer to downgrade a cable, but if it was my house I would want it as its supposed to be! and if its in the old colours as well! it would bug me! I'm just a bit ---- about it is all!
'If it isn't broken, don't fix it' is my general work ethic! unless its going to be really hard to replace at a later date, and it makes sense to rewire now that is.

 

[markc123]

Just a case of bite the bullet here im afraid my friend, no point ripping all of it out when it works and tests out properly....If it's a old install just makie sure the metal back boxes are earthed and thats about all you can do along with adding the colour coding stickers to the cu or sleeving the old r&b

 

[Farmelectrics]

couldnt you change it to a 4mm radial

 

[Geoffsd]

There's nothing wrong with it.

 

[kingeri]

Are you sure the 4mm cable IS 4mm and not the imperial 7/029-7/036?/ That may make a lot more sense!! lol!!! Maybe that in the not too distant past a fault occured on one leg of this ring and got replaced with 2.5mm!!

The dead give away here, would be the cables CPC in imperial cable it will be multi strand 3/029, whereas on a 4mm it will be a solid core....

Thanks for that Eng, but it did occur to me at the time, was the first thing I checked! The CPC is solid core. I have encountered some 7 stranded T&E before which appeared to be aluminium coated with copper....was awful stuff, brittle as hell. I remember then initially thinking it was 4mm, but fused it at 20a at the DB cos I didn't trust it!

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couldnt you change it to a 4mm radial

Definately not, plus what'd be the point?

 

[Fin170]

I'd stick it on a 20A breaker if there is an excessive amount of spurs on spurs etc

 

[kingeri]

There was another thing I found as well, an unused (but still live) cable terminated in a connector block in a socket backbox of another circuit. Not great, as there would still be live parts in there when that circuit was switched off. Can't find where it's supplied from, it's not from a socket, looks like a JB plastered in behind the kitchen units.

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I'd stick it on a 20A breaker if there is an excessive amount of spurs on spurs etc

I've managed to work the spurs into the ring.

 

[SKY]

I have seen things like this before, I have also seen the opposite where 2.5 steps down to 1.5 in a ring.
When I took the cover off the CU I thought that someone had piggy backed a light circuit onto a power circuit!!

Until I took off some socket faces to find some 1.5mm looping - The customer would not pay for it to be changed and would not let me downrate the MCB so I made a note on the cert for the shower I installed and left.

I think the guy thought I was sniffing for extra worked and was making it up, same old saying. Its work for 10yrs mate.

I just hope that one day if his heating breaks that he does now plug a few 2-3KW heaters in!

 

[Engineer54]

Thanks for that Eng, but it did occur to me at the time, was the first thing I checked! The CPC is solid core. I have encountered some 7 stranded T&E before which appeared to be aluminium coated with copper....was awful stuff, brittle as hell. I remember then initially thinking it was 4mm, but fused it at 20a at the DB cos I didn't trust it!

The old imperial 7/029-7/036 is a far superior cable than the solid 2,5mm cable we have today, also has a better CCC!! In fact, all the solid core cables should be stranded. It'll make for far easier pulling in and final dressing is a breeze!! lol!!! All our conductors on this project are stranded, so it's not as if manufacturers don't make/produce stranded 2.5mm...


The cable you are referring too is ''tinned copper'' conductors, not aluminium coated copper. Never seen a brittle tinned copper conductor just over worked conductors. Probably more a case of you not being experienced/used to smaller stranded conductors. Plus the more you work any copper conductor or copper sheath, it will harden and snap...