Split Concentric as a submain

frontier219 · Feb 9, 2015

Hi All,

Having a little discussion with my old man over a job. The job is a domestic property, the CU is around 7 metres in cable length from the meter. There is a switch fuse around 4m from the meter, in a cellar. However, the tails are run very shoddily in an old bit of water pipe and then hanging across the ceiling. We have suggested ripping the whole lot out and running a new submain in, with an isolator at the mains. We are deciding what cable to use. I have suggested split concentric, as it is smaller and easier to run than SWA. However, my dad seems to think split concentric cable should not be used in this way, as he 'heard something about it a few years back'. We can't find anything definitive on the subject so I wondered if anyone on here could give us a bit more of a clue?

Cheers,

Dan

GEOFF S · Feb 10, 2015

Its debatable as to wether it complies due to the neutral earth arrangements. SWA a better choice.

Cheers

frontier219 · Feb 10, 2015

TJ Anderson said:
I was referring to stranded, although you are correct you can get solid also.

Wasn't aware that this existed. When I was an apprentice I had a job with 25mm hi-tuff and it was solid conductors. Harder than bending conduit IMO. As they do stranded, this may be a better choice, yes.

frontier219 · Feb 10, 2015

GEOFF S said:
Its debatable as to wether it complies due to the neutral earth arrangements. SWA a better choice.

Cheers

Debatable how? I'm not proposing it be buried in a wall.

Engineer54 · Feb 10, 2015

frontier219 said:
If I decide on this method, I shall post them up! Thanks for your help.

Going by your posts here, i thought you had already made up your mind, especially when you told us you were bringing in an old hand to help you. So I'm now as they say, Confused Dot Com!! lol!!

frontier219 · Feb 11, 2015

Engineer54 said:
Going by your posts here, i thought you had already made up your mind, especially when you told us you were bringing in an old hand to help you. So I'm now as they say, Confused Dot Com!! lol!!

Not quite, but almost, yes. Your words discouraged me a little, though! The old hand I spoke to thinks that I'll cope just fine with the terminations, but is quite happy to come and give me a hand. However, as I stated in the first place, this came about through a discussion with my old man. The prospect of stranded hi-tuff has given me something else to consider as well.

GEOFF S · Feb 11, 2015

frontier219 said:
Debatable how? I'm not proposing it be buried in a wall.

Well one of the issue's is the neutrals, seperated via insulation, now underfault condtion its possible for just one of the neutrals to be in the fault path, you will need to show in your calculations that this isnt a problem, also the level of insulation is not that of the line conductors. its debatable as i say, there are better choice cables and wiring methods out there.

Cheers

VoltzElectrical · Feb 11, 2015

No-one has mentioned price yet! Split concentric is a special order and is very expensive compared to SWA, which the wholesalers will have on a drum in the store.

Split-con is a fantastic cable, but as has been stated, has too many considerations to be taken into account.

1. Expensive
2. Hard to terminate neatly and easily
3. May need RCD protection depending on run.

SWA is the way forward here.

Knobhead · Feb 12, 2015

Much as I like split concentric the thought of cost had gone though my mind.

The company I worked for dealt direct with the cable manufacturers so me ordering 100m of 35mm[SUP]²[/SUP] split con didn’t even bat an eyelid.

The only time I’ve used it was in an office block which didn’t fall in our normal standard
M&Q regs. I thought it was great stuff to work with. To dress it properly takes a bit of time but once you’re used to it takes no longer than SWA.

If space and bending radius are a problem, split con does it for me.

frontier219 · Feb 12, 2015

Tony said:
Much as I like split concentric the thought of cost had gone though my mind.

The company I worked for dealt direct with the cable manufacturers so me ordering 100m of 35mm[SUP]²[/SUP] split con didn’t even bat an eyelid.

The only time I’ve used it was in an office block which didn’t fall in our normal standard
M&Q regs. I thought it was great stuff to work with. To dress it properly takes a bit of time but once you’re used to it takes no longer than SWA.

If space and bending radius are a problem, split con does it for me.

This is, really, the crux of the issue I'm having, hence why I thought this cable would be suitable. Cost actually doesn't seem to be as prohibitive as people are saying, my local wholesaler has quoted me a per metre of £5.35 for 25mm split concentric, which is cheaper than anywhere I can find SWA online.