Concentric cable?

[rorie]

I'm wiring up a new consumer unit just now. I need to run a longer cable from the hydro box to the new consumer unit (in a new location).

To save costs, I'm wiring the consumer unit and getting a sparky over to check, then hook it up to the hydro unit. When the sparky was out to have a look, he said to get 25mm concentric cable.

I want to hook it into the consumer unit, but its not quite what I expected. The existing arrangement is has the live, neutral and earth. This has multiple neutral tails!

Cant find anything online of how to wire it into the consumer unit. Any suggestions?

Worst case, i'll just get the sparky to install both ends!

 

[Parm]

isn't it the type that goes round and round in a circle, usually starting from the middle ??

Ill get me coat

 

[Welderpaul]

Strip all the neutrals and wire them in together. Live to live, earths to earth. Sometimes used by the DNO's for service feeds as it can be direct buried but I've seen a lot of split concentric cable on new builds for sub main distribution where you exceed the maximum length for meter tails.
As long as it's not CNE as this shouldn't be used beyond the cut out.

It came in quite a while ago as I remember, used to lay it for street light feeds.

 

[rorie]

The cable comes out the hydros box and travels up the external wall (exposed to the environment) before going into the eaves of the house. Perhaps this would be the reason he suggested concentric rather than meter tails?

The cable that's in place just now looks like some kind of armoured cable, but it has three separate cables inside, all with their own isolation covering....

 

[WorkshopChris]

If this is what you have inside your armoured
http://www.doncastercables.com/images/products/large/splitcon.jpg
http://www.doncastercables.com/cabl...bution/PVC-Insulated-Split-Concentric-Cables/
Then you need to twist all your neutrals together and the earths if bare cover with sleeving.

I haven't seen a armoured version of this just the pvc coated stuff the dno use for final connection into a cutout.

 

[BrokenBiker]

As above, treat all neutrals as one, all of the earths as one etc...

 

[rorie]

Had a closer (but not too close) look at what is there already and i can see its a concentric with the N & E bound.

Thanks for the help!

 

[J.F]

What is a Hydros box?

If it is fed from your consumer unit to something outside why not use steel wire armour (swa) cable.

Concentric and split concentric are what's used by DNO's to feed houses and small units, it's not armoured and is designed to be, and often is opened up live by the DNO's.

 

[brightspark]

the golden rule on length of meter tails to consumer unit is 3mt otherwise any longer u need a switchfuse fitted then outgoing cable to your consumer unit just run out in 25 mm swa and gland either end job done

 

[GW8IZR]

What is a Hydros box?

Scottish Hydro are a supplier...

 

[rorie]

I looked at both 25mm concentric and 25mm three core at the wholesalers. The 3 core overall size was a hell of a lot thicker. Is that why they use the split concentric? Or was he showing me different gauge cable?

As the cable runs outside, I guess I'd be safer running swa over the concentric, so will go for that!