Meter tails in cavity wall

[Spirite]

I'm just in the process of having an extension built and the electricity meter is to be moved to the outside in a meter box. The consumer unit is to be mounted about 2m from the meter with the meter tails running through the cavity.

1. Is it necessary to use conduit for the meter tails and earth in the cavity wall?

2. Will 32mm diameter conduit be adequate for meter tails of 25mm2 and earth of 16mm2

3. Would 32/40mm waste pipe be suitable for this or would I need conduit specific for electric cables?

Many thanks.

 

[Carloss]

1) No need for conduit unless using single core cables because it only has one layer of insulation.

2) 40mm should be ok as long as nothing else is going through.

3) Use proper electrical accessories.. high impact pvc conduit?; someone may cut through the waste pipe in the future if they think it has no use....unless you wish to mark it all the way down...?

 

[Adam_151]

1) Using conduit will protect the cable insulation from any thermal insulation that gets put in the cavity, which can do bad things to the plasticiser in the cable insulation.

2) unsure

3) Use proper electricial conduit, its manufactured to a set of british standards for electrical conduit, waste pipe is not.

extra point) Be careful bridgeing the cavity with anything, you don't want to end up with moisure traveling between the two, maybe you should ask in the brickwork forum on here (if one exists - I can't remember)

 

[Spirite]

Many thanks.

I decided to use flexible electrical conduit. Given the insulation in the cavity, this appeared to be the most sensible option. I ran two lots of 25mm^2 conduit - one for the neutral tail, and one for the live tail and earth cable (25mm^2 conduit didn't have capacity to carry all three cables and larger diameter conduit and associated accessories was impossible to get hold of at short notice).

 

[plugwash]

conduit unlike cable is sold by diameter not area

i presume you mean 25mm conduit

 

[Spirite]

I do realise that and indeed meant 25mm diameter not 25mm^2 area - I just went mad momentarily!