The old barn electrics

[La Poste]

Greetings all.

My neighbour has just had a garage built in the shape of an old barn.
We live in the sticks and I guess the only way the architect could get it through planning was to make it this way.
It's in keeping with the surrounding area.

As he is my next door neighbour he has asked me to do the electrics.
The supply is a 2.5mm SWA buried underground.
The system is a TN-S with the transformer on a pole in the field out back.

I will have a quick look at it later but I have a couple of small queries if anyone can enlighten me.

As the supply is SWA which means it is earthed in a metal housing does it need to be RCD protected.
I don't think it does, I am thinking of a distribution circuit you know like they supply street lights with and a 5 second disconnection time.
As the supply is TN-S from an underground supply cable I don't think exporting an earth from the main house will be a problem.
I could TT it and would probably get low results for EFLI but I would prefer to keep the distributors earth.
Can anyone see any problems with exporting a TN-S earth?

The other question is I want to encase all the cables in black galvanized metal conduit to give it a more pleasant look but I am little concerned about the sockets.
What would members consider to be the best and most attractive sockets and switches to put on.
They would be metal surface mounted supplied by cables in black enameled conduit.
Has anyone any recommendations?

I will take some pictures in due time but I wondered if anyone has ever done a job like this.

Many thanks.

 

[EastAnglian]

Before we loose sight of the question don't forget that La Poste is working with a pre-installed cable and he will need to satisfy himself that the CPC meets the requirements of section 543 and table 54.1.

If its a 3 core SWA then job done - easy - but if not then it will be necessary to confirm that the CSA of the armour meets the Regulation.

If it does not then TT is the remaining option.

 

[topquark]

Nice conduit job!! Shows that you can make a decent job of PVC conduit when done right..

PS ...I like the artexed ceiling in your garage, ...different!! lol!!!

About 13 years old now, so done in the proper colour singles as well

 

[johnboy6083]

Before we loose sight of the question don't forget that La Poste is working with a pre-installed cable and he will need to satisfy himself that the CPC meets the requirements of section 543.

If its a 3 core SWA then job done - easy - but if not then it will be necessary to confirm that the CSA of the armour meets the Regulation.

If it does not then TT is the remaining option.

The SWA will be constructed to a british standard. This will list the available cables sizes, and the armour CSA, along with other information

 

[Engineer54]

Iv'e Never yet come across a SWA cable under 95mm2 where it's armouring doesn't meet the requirements of being used as the cables CPC.

In this instance the armouring needs to have a minimum CSA of 5.7mm, a standard 2 core SWA cable has a armouring CSA of 17mm. So I think that the SWA will JUST meet CPC requirements!! ...lol!! I think we can now all agree then that the SW Armouring will be just Fine!! lol!!

 

[La Poste]

If your neighbour later wants to have a water supply in there, tell him to pipe it in, in Plastic pipe. lol!!!

I should have thought of that straight away LOL.
There's nothing like missing the obvious to make me feel daft.

 

[yellowvanman]

Iv'e Never yet come across a SWA cable under 95mm2 where it's armouring doesn't meet the requirements of being used as the cables CPC.

In this instance the armouring needs to have a minimum CSA of 5.7mm, a standard 2 core SWA cable has a armouring CSA of 17mm. So I think that the SWA will JUST meet CPC requirements!! ...lol!! I think we can now all agree then that the SW Armouring will be just Fine!! lol!!

If I remember correctly the ECA were saying that SWA up to 400mm was sufficient for CPC requirements, although I think 240mm was borderline.

 

[telectrix]

check the thread "can we use the armour of SWA as cpc" there's a chart showing all sizes , and whether the armour is ok as CPC

 

[Engineer54]

check the thread "can we use the armour of SWA as cpc" there's a chart showing all sizes , and whether the armour is ok as CPC

There are 2 chart/tables in that thread, i tend to use the one Spin posted (i think on page 4 /post 37 or thereabouts), and have been using that table for quite a few years now without incident. I don't use the table Lenny posted, far too many calculations to have make on too many cable sizes etc, before getting definitive results.

To be honest, these day's i only look up such tables when my mind goes blank...lol!! As i'm using SWA cables for much of this and past projects distribution systems. So they are almost imprinted, in my mind, even the cables that i've had to calculate to prove compliance.. lol!!!

 

[La Poste]

Here's some pictures of the barn.

It's a garage really in the shape of a barn.

 

[Octopus]

So I guess the relevent question also is whether plumbing in a new "building" on the end of an existing SWA cable is notifiable under Part P?

For me I'm not sure you may get away with simply providing an EIC but others may have alternative opinions.