Metal Consumer Unit

[Newpark7]

Hi All

Just a quick question if anyone can help, doing a quote for Garage electrics and just noticed in the OSG pages 24 & 25 that for TT installations insulated enclosure or further mechanical protection to meter tails.

As I will not be exporting the dwelling PME supply and will be creating a separate TT system, does this mean I cannot fit a metal CU?

Thanks


Mark

 

[not clever]

Use an adaptable box next to the cu to terminate the swa (if thats what you are using) & pme, take line & neutral tails into insulated cu at the garage.
No need to rcd the submain if designed as a distribution circuit on a TN system

 

[sparks1234]

why not put a large stuffing gland on so that there is no earth connection?

 

[Newpark7]

Hi Sparks

Not used these before I take it they are insulated glands of some sort?


Mark

 

[sparks1234]

Hi Sparks

Not used these before I take it they are insulated glands of some sort?


Mark

yes, just a plastic gland like you put flex through but bigger

 

[Newpark7]

A good idea - Thanks, would that then allow me to use a metal CU? or am I misunderstanding the OSG?


Mark

 

[sparks1234]

A good idea - Thanks, would that then allow me to use a metal CU? or am I misunderstanding the OSG?


Mark

I dont see why you cant use a metal consumer unit, I did one last week which went in a metal shed and was a TT system, I used a metal unit for mechanical protection as it is a store for a valetting bay at a car dealers

 

[Spudnik]

Tricky one this as if it is a metal CU on a TT, then it should have RCD protection to the incoming tails.

 

[Newpark7]

Tricky one this as if it is a metal CU on a TT, then it should have RCD protection to the incoming tails.

Hi Jason

I can see where it says mechanical protection to meter tails, where does it say RCD protection to the meter tails?


Mark

 

[Des 56]

Tricky one this as if it is a metal CU on a TT, then it should have RCD protection to the incoming tails.

Not absolutly necessary but sensible

[531.4.1].
It permits a metal enclosure as long as the supply to the boards rcd meets class 2 requirements
Bushing the entry where the supply enters or using double insulated tails

 

[Newpark7]

Not absolutly necessary but sensible

[531.4.1].
It permits a metal enclosure as long as the supply to the boards rcd meets class 2 requirements
Bushing the entry where the supply enters or using double insulated tails

Hi Des


Interesting - thanks for that.

Mark

 

[Spudnik]

Not absolutly necessary but sensible

[531.4.1].
It permits a metal enclosure as long as the supply to the boards rcd meets class 2 requirements
Bushing the entry where the supply enters or using double insulated tails

True Des, but i have never seen a class II metal CU

And the tails wont be DI as it will be a sub main, assumably (what a good word ) SWA

 

[Des 56]

, assumably (what a good word ) SWA

Assumably
To take upon oneself: assume responsibility


Excellent choice of word
This thread could have started and ended with that word as the comprehensive answer