How would you do it?

[dave2]

I've a new build to start shortly.

It has an external meter cabinet flush mounted with the outer brickwork.

The tails will be 20m so I will have issues with the relevant DNO as to protection etc. but how would you run the tails from the cabinet to the cu?

I see 3 choices:

1 Straight through inner wall, earthed metal capping to ceiling void then internally to cu. (Would need to identify safe zone for run to ceiling height by socket or other).

2 Run tails from cabinet, 2m up cavity then through inner wall to ceiling void and onto cu. (cavity is filled with glasswool insulation so possibility of deration).

3 Externally from cabinet up outside wall and through to ceiling void. (What to use to protect tails externally and keeping inside of cabinet watertight).

The internal walls will be dot and dab plasterboard

I'll be interested in your ideas.

Dave

 

[NozSpark]

I'd go straight through the inner leaf and into a switch fuse,, then using SWA or Split Con take whatever route you want to the CU

 

[Lurch]

1 Straight through inner wall, earthed metal capping to ceiling void then internally to cu. (Would need to identify safe zone for run to ceiling height by socket or other).2 Run tails from cabinet, 2m up cavity then through inner wall to ceiling void and onto cu. (cavity is filled with glasswool insulation so possibility of deration).

3 Externally from cabinet up outside wall and through to ceiling void. (What to use to protect tails externally and keeping inside of cabinet watertight).

You seem to be missing the switch fuse on all these options. Can we assume you are putting that in the meter cupboard?

Split concentric as a submain, through the back of the meter cupboard and up the wall internally.

 

[NozSpark]

You seem to be missing the switch fuse on all these options. Can we assume you are putting that in the meter cupboard?Split concentric as a submain, through the back of the meter cupboard and up the wall internally.

And there was me trying to be nice to the DNO boys

 

[Lurch]

And there was me trying to be nice to the DNO boys

800KMF in the corner won;t be a problem, filling 3/4 of the cupboard with a Wylex W110M could make them a little upset!

 

[NozSpark]

800KMF in the corner won;t be a problem, filling 3/4 of the cupboard with a Wylex W110M could make them a little upset!

You're not wrong!

 

[dave2]

800kmf will be ok in the cabinet if that is what dno require.

Incidently on a previous request to dno for protection to extended tails they said it was not neccessary. This was given in writing.

As far is 25/25/16 split concentric, what diameter would this cable be, is it easy to route through timber joists and can it terminated easily in an insulated consumer unit?

Dave

 

[Lurch]

Incidently on a previous request to dno for protection to extended tails they said it was not neccessary. This was given in writing.

Not heard that before. However, for 20m I would probably stick a switchfuse in anyway FWIW.

As far is 25/25/16 split concentric, what diameter would this cable be, is it easy to route through timber joists and can it terminated easily in an insulated consumer unit?

Overall diameter is about 20mm and terminating it is just a case of TRS gland in the CU and terminate in the KMF as you would a 6242Y cable. This is another reason I'd fit a KMF, because you can;t tidily terminate a split con into a meter.

 

[wozz]

bit off topic but i too have worked on a job where the DNO did not require switch fuses for the armoured supplies to eight flats

 

[Andy™]

Not heard that before. However, for 20m I would probably stick a switchfuse in anyway FWIW.Overall diameter is about 20mm and terminating it is just a case of TRS gland in the CU and terminate in the KMF as you would a 6242Y cable. This is another reason I'd fit a KMF, because you can;t tidily terminate a split con into a meter.

you can get heatshrink designed for terminating split/straigh con

 

[Lurch]

[quote name='Andy

 

[initforthemoney]

Dont forget RCD protection if the cable is buried internally.

 

[Andy™]

Dont forget RCD protection if the cable is buried internally.

not applicable to SWA

 

[NozSpark]

not applicable to SWA

Or split concentric,,,,,,

Unless it's TT that is

 

[Andy™]

split con does require RCD'd if buried in a wall. the earth doesnt fully surround the live conductor

 

[dave2]

[quote name='Andy

 

[Andy™]

earthed steel capping does not comply, and never has

split con is treated the same as T&E as far as RCD's and zones etc are concerned.

SWA does not need an RCD, and can go anywhere in a wall

 

[wozz]

noz was correct in the 16th edition, but split con got taken out in the 17th im sure theres a wiring matters article about it somewhere.

 

[initforthemoney]

Spilt con should be treated the same as t&e regardless of whether its in the regs or not.

It does not have any form of mechanical protection like SWA does.

 

[wozz]

it was more to do with safely disconnecting the supply than mechanical protection, hence why we have flexisheild cables allowed to be buried without RCD protection.