Garage Supply?

[person]

I am giving a qualified electrcian a hand to wire my garage etc. He took care of getting the cable etc. Right now theres a 6mm or 4mm (4-core) I can't remember, running from a metal through box in the house beside the mains board to the garage where the board is going to be. Theres then a 6mm twin and earth running from the metal box to the mains board (on a 4oamp mcb) so obviously they are to be joined in the box in connectors. He has the black from the 4-core in earth sleeving and crimped to the metal box then has the red yellow, blue in seperate connectors and the brown, blue and earth from the twin in seperate connectors. Why would there be a need for a 4-core swa surely a 3-core would do? I would ask him myself but he's away on holiday for a couple of weeks. The board in garage is only for sockets and lights. Thanks in advance.

 

[properleckie]

Sounds like he is using up some very old cable he has, since colours changed several years ago.

The old steel wired armoured 4 core should really not be used but if he fully sleeves all cores at both ends with new (brown/blue) it could be argued it complies, but suggest he charges you 5 year old price for it!

Make sure you get a full set of installation certificates, and that he registers the work with his 'competant Persons' scheme provider, so that you get a registration document from LA building control.

 

[person]

Yeah I did wonder if he was just using old cable as I though three core would be enough i.e live, neutral,earth? So what does he do with the spare core at each end? and I take it he will just join the earth coming from the house cu to the one that's crimped on the through box, is that safe?

 

[flameport]

4 core isn't needed for a normal supply.
3 core probably isn't required either, 2 core would be suitable in many cases.

The 6mm T+E at the end sounds like a mess. Why not put the metal box against the CU and take the individual wires from the SWA through it and into the CU?
Or fix the SWA directly into the CU.

 

[ricicle]

I would ask him myself but he's away on holiday for a couple of weeks. .

That old chestnut again

 

[Alisdair]

three core is the answer as the armour should not be used for earth although it needs to be earthed. He probably won't connect the other core. At the end of the day if he sleeves it, it will be ok

 

[Aragorn84]

Whats wrong with using the armour as the CPC as long as it meets the appropriate calculations?

 

[properleckie]

I was going to say that!
the 'spare core(s)' must be connected to earth and not left 'floating' as induced current from others can produce a 'shockingly' high voltage.
If 'he' is going to use twin & earth to an adaptable box and connect the earth to a core of the armoured it must also be connected to the box at house end,
(never spotted that Ricicle us leckies do seem to have lots of long hols!)LOL