1.5mm meter tails

[BigSpark]

Evening All,

I attended a job today to disconnect an Alarm System at a ground floor flat. On taking the consumer unit front off, discovered the incoming neutral tail to be 11 x 1.5mm single core cables which needless to say aren't all tight and secure in terminals. The incoming line looks to be 25mm 6181y albeit without the grey sheath. The main earth is 4 x what looks like 4mm solid core. They all come into the board in 1 grey sheath then split off.

Traced back, at some point in the flats roof it connects to an SWA ( point of connection is not accessible ) then back to a switch fuse with 80a fuse.

I dont think its an option to run any new cables ( which is my ideal method to sort issue) as its all in ceiling void with no obvious access but I am exploring this possibility with the flats owner/ building maintenance people.

The only option I can think that might help is heat shrink round the cables and ferrule the end but im not really happy with it.

Has anyone seen this before? Any ideas what's the thinking behind it? And what I can do make it safe?

 

[westward10]

Split concentric cable, nothing wrong with it although connecting all those strands can be an issue. I am surprised this can flummox so many electricians.

 

[LewisM]

Looks like some sort of split concentric cable.

 

[telectrix]

that looks like split concentric cable incomer. single core L with the multitude of N conductors concentric aruond it. standard practice. just need to make sure all the N conductors are secure,

 

[telectrix]

me too slow. time of day, well past beer o/clock. well that's my xcuse and i stand by it. rain or shine, and as zebeddee says,,, BOING< Time 4 bed.

 

[BigSpark]

Thanks guys, I had thought it might split concentric but have never worked with it so wasn't sure how it looks. Always thought it would be in a black XLPE sheath not grey twin and earth looking sheath. I may be wrong but is split concentric a non standard cable? And really only usually used by the DNO?

 

[BigSpark]

No flumoxing westward, just asking advice matey ?

 

[westward10]

Depends on what you deem a non standard cable.

 

[BigSpark]

Depends on what you seem a non standard

Pretty sure its not me deeming a cable non standard but I think you know what I'm asking. As I've said not worked with split concentric before, would ferrule be the best option in your opinion?

 

[pc1966]

I would probably use a ferrule so they are all "as one" for wrangling.

I don't know if the insulated 16mm ferrule would accept the strands with insulation though, so it might be a simple uninsulated one and if necessary some heatshrink to avoid any exposed conductors if after crimping you find one of the little buggers has slipped back a bit.

 

[BigSpark]

I would probably use a ferrule so they are all "as one" for wrangling.

I don't know if the insulated 16mm ferrule would accept the strands with insulation though, so it might be a simple uninsulated one and if necessary some heatshrink to avoid any exposed conductors if after crimping you find one of the little buggers has slipped back a bit.

Thanks PC1966. Appreciate the constructive reply. Il post a picture when it's all sorted ?

 

[Vortigern]

I don't like it.

 

[Spoon]

I would probably use a ferrule so they are all "as one" for wrangling.

I don't know if the insulated 16mm ferrule would accept the strands with insulation though, so it might be a simple uninsulated one and if necessary some heatshrink to avoid any exposed conductors if after crimping you find one of the little buggers has slipped back a bit.

I was just about to ask how people wire all these 11 wires into something until you put this. I was going with the same idea as yours but then to add solder to it as well, so that you get a better bonding. Not sure if that's over the top...

 

[radiohead]

Cant see any reason to get involved, no sign of thermal stress to those conductors. You were only there to disconnect something, Just make sure terminals are tight.

 

[BigSpark]

Cant see any reason to get involved, no sign of thermal stress to those conductors. You were only there to disconnect something, Just make sure terminals are tight.

Good customer, didnt have a lot of time as, like you said i only popped round to disconnect. Potential of loose neutral cables if they aren't tight and engaged properly. Not something I'd like to leave to chance but each to there own

 

[freddo]

I wouldn't worry, concentric and split concentric cable is used extensively by DNOs and they don't fit ferrules, just jam the conductors in the terminals.

 

[MJPD29]

Evening All,

I attended a job today to disconnect an Alarm System at a ground floor flat. On taking the consumer unit front off, discovered the incoming neutral tail to be 11 x 1.5mm single core cables which needless to say aren't all tight and secure in terminals. The incoming line looks to be 25mm 6181y albeit without the grey sheath. The main earth is 4 x what looks like 4mm solid core. They all come into the board in 1 grey sheath then split off.

Traced back, at some point in the flats roof it connects to an SWA ( point of connection is not accessible ) then back to a switch fuse with 80a fuse.

I dont think its an option to run any new cables ( which is my ideal method to sort issue) as its all in ceiling void with no obvious access but I am exploring this possibility with the flats owner/ building maintenance people.

The only option I can think that might help is heat shrink round the cables and ferrule the end but im not really happy with it.

Has anyone seen this before? Any ideas what's the thinking behind it? And what I can do make it safe?



View attachment 62156

Awful lot of copper on show in the mcbs

 

[BigSpark]

Awful lot of copper on show in the

 

[BigSpark]

Amazing that I've probably changed 300+ consumer units. Attended 1000's of jobs so looked in nearly all of those consumer units. All jobs around the county Nottingham, Leeds, Stoke on Trent, Stafford, Birmingham, Leicester, Coventry, Derby, Northampton and never seen split concentric used at all. And only ever heard it used by DNO. Cray Cray

 

[sparksites]

Amazing that I've probably changed 300+ consumer units. Attended 1000's of jobs so looked in nearly all of those consumer units. All jobs around the county Nottingham, Leeds, Stoke on Trent, Stafford, Birmingham, Leicester, Coventry, Derby, Northampton and never seen split concentric used at all. And only ever heard it used by DNO. Cray Cray

Me too. In 21 years I've only seen it once, when I mistakenly flagged it on an EICR.

 

[westward10]

DNO supplies for PME systems will use a concentric cable where you have the phase core and a single PEN surrounding it. Split concentric as in this case have the phase core and separate neutral and earth surrounding it, not normally used by DNOs but is used for SNE supplies (Separate Neutral Earth).

 

[Grant1987]

DNO supplies for PME systems will use a concentric cable where you have the phase core and a single PEN surrounding it. Split concentric as in this case have the phase core and separate neutral and earth surrounding it, not normally used by DNOs but is used for SNE supplies (Separate Neutral Earth).

I’ve come across this couple of years ago. It’s to do with harmonics this install is most often used in residential block buildings where supplies are run together and apparently reduces harmonic distortion baffled also

 

[Taylortwocities]

I was just about to ask how people wire all these 11 wires into something until you put this. I was going with the same idea as yours but then to add solder to it as well, so that you get a better bonding. Not sure if that's over the top...

I seem to remember that solder isn’t permitted in this situation, or maybe that’s for tri-rated conductors?

 

[Spoon]

I seem to remember that solder isn’t permitted in this situation, or maybe that’s for tri-rated conductors?

Solder alone is not permitted.

 

[BigSpark]

Me too. In 21 years I've only seen it once, when I mistakenly flagged it on an EICR.

Strange isn't it. I think for me it may be because i havnt worked in a lot of flats. Maybe only 50 ish, 99 percent is either houses or commercial units

 

[Taylortwocities]

Solder alone is not permitted.

View attachment 62167

Thank you. The N wires in split con are solid, so it looks like solder can be used.
(But it shouldn’t be necessary )

 

[loz2754]

Thank you. The N wires in split con are solid, so it looks like solder can be used.
(But it shouldn’t be necessary )

Doesn't the reg also say multiwire? I'd say that would include the split concentric neutrals.

 

[Spoon]

Thank you. The N wires in split con are solid, so it looks like solder can be used.
(But it shouldn’t be necessary )

If properly crimped into a ferrule, then soldering should not be required, but I was thinking of just making the centre cables in the ferrule more sturdy while installing it. I could be wrong in my thinking...

 

[Spoon]

Doesn't the reg also say multiwire? I'd say that would include the split concentric neutrals.

Yep, I agree. But seeing that we are not using solder alone for connection into screw terminals and the screw is clamping onto the ferrule, then I can't see a problem, from a reg point of view, with adding solder to the cables going into the ferrule, after it's been crimped.

 

[Mike Johnson]

Can't remember, but think it was one of the mods who showed a very neat way of finishing a multi core earth cable by wrapping one extended bare core around the others, can't find the picture, but I am sure you get the idea.

It was Westwood 10