Garage supply/install

[babyshanks]

Hi guys, I have a few questions I need answering.

Firsty, I've been asked to wire up a garage. The garage has a supply to it which stops outside the house. The supply is spurred from the upstairs ring in 4mm t&e. Can I run a 4mm SWA from a waterproof box on the side of the house to the garage which is about 1 meter away into a 30mA 2 way cu? Do I have to connect it into an FCU before it reaches the board? In the board there is going to be a power circuit supplying 4 double sockets. One for freezer, one for tumbledryer, not sure what but something else on another and the other will be rarely used. Also a lighting circuit going to junction box feeding a one way light and a 2 way light. Is this too much to put on considering it has been spurred off a ring?

If this is too much have you any suggestions? I cannot run a new cable from the board in the house.

Cheers guys any help is greatly appreciated as always

 

[malcolmsanford]

First your going to have to make sure that the socket you are spurring off is not a spur itself but part of the ring.

If it is part of the ring all well and good. Though of course as you say it would be better to have the supply go back to the CU.

The 4mm cable should be good enough for the 32amp protection device. Though I personally would be in favour of trying to incorporate into the ring itself, by simply extending the legs via crimps inside the back box.

If your ring final as already got RCD protection then no need to put another RCD in the garage. Does it?

I would configure your CU in the garage as a A3 radial with perhaps a 20amp MCB and lights on 5amp MCB

 

[Knobhead]

I’m booking in to the dentists, I can feel a toothache coming on.

 

[Silly Sausage]

I can feel a toothache coming on.

Mają Państwo got wszelkich miejsc?

 

[babyshanks]

Thanks for clearing that up malcolmsanford. The board in the house is well old, and is not RCD protected so definitely need to put some RCD goodness in the garage. I was planning on 20A for the power and 6A for the lights.

But I read somewhere that if you spur off the ring main then you need to put in an FCU before it reaches the CU in the garage, is this true?

Cheers mate

 

[malcolmsanford]

No as long as you can satisfy In does not exceed Iz which the 4mm should do and that the Zs of the new spur can still operate the protection device at the original CU then you should be fine.

 

[oxocube]

You need to think again, an unfused spur off a ring final is limited to one twin socket. If you want more than one socket you have to spur off via a fcu, this will then limit the current to 13 Amps.

 

[malcolmsanford]

NO OC all he is doing is using that CU as his spur point. That is why I suggested really to extend the ring final to feed the garage CU.

It's not ideal what he is doing but there is no real problems with it. I would not to be ohnest thought there is much danger in unbalancing the load

 

[oxocube]

What I said is correct and I was'nt trying to contradict your advice.

But if he can extend the ring as you suggested, he should include the garage sockets on the extended ring and do away with the CU. The garage lighting can come off a switched fcu. And either fit individual rcd sockets or fit an rcd at the house cu for the whole extended ring circuit.

 

[Knobhead]

Mają Państwo got wszelkich miejsc?

Gdzie byłby wy spodziewacie się tego jest?

 

[Silly Sausage]

I've got to find a better online translator or start hanging around outside Polish clubs.

 

[Knobhead]

Wy dawaliście grę daleko!

 

[Silly Sausage]

Bog off!
I'm getting this... Ye dawaliście game far! ???

You can have fun by continually translating stuff back and forth, come out with some real nonsense.