Earthing for an outdoor install in a barn

[SparkyChick]

So if the Barn or outhouse develop an earth fault and you are relying on the CU RCD in the house then all the house goes out with the outside buildings if I am understanding this correctly?

It's a split load board and I agree, it's not ideal... but the cable is T+E and it runs an unknown route through the house, so to be sure it complies, it really should be RCD protected at the origin.

I could convert the board to include a non-RCD protected section and put the barn supply on an RCBO, but that just gives me the chills.

Rock and a hard place is my view.

 

[SparkyChick]

I should add I could also add a stand alone board, but there is no room for that.

 

[The Ghost]

So I was thinking of a stand alone supply with discrimination at the supply and TT at the barn and on. Keeping it separated from the residential. But then I suppose it depends on what your supply is as well. I guess along with you it is TT.

 

[Richard Burns]

I but the cable is T+E and it runs an unknown route through the house, so to be sure it complies, it really should be RCD protected at the origin.

If the earthing is TT then all circuits need to be protected by an RCD

Just out of interest what size T&E is supplying all these various loads required? Just wondering about max demand and MCB sizing.

 

[SparkyChick]

So I was thinking of a stand alone supply with discrimination at the supply and TT at the barn and on. Keeping it separated from the residential. But then I suppose it depends on what your supply is as well. I guess along with you it is TT.

Ideally, I'm with you a separated supply would be grand, but there literally is no room.

If the earthing is TT then all circuits need to be protected by an RCD

Just out of interest what size T&E is supplying all these various loads required? Just wondering about max demand and MCB sizing.

The T+E that runs to the barn looks to be 16mm, from the looks of what's in the barn it used to feed the milker. In terms of capacity, we're looking at two LED bulbs, three 5ft twin fluorescent battens, tumble drier and pond pump.

 

[The Ghost]

I suppose I would at least suggest emergency lights so they can see when everything goes out then. But what about RCBO residential sockets and main switch 100ma then RCBO outside? Oh just re-read and see its a split load maybe that wouldn't work then.

 

[SparkyChick]

I suppose I would at least suggest emergency lights so they can see when everything goes out then. But what about RCBO residential sockets and main switch 100ma then RCBO outside? Oh just re-read and see its a split load maybe that wouldn't work then.

No, it's a royal pain in the posterior. Personally I wouldn't have put the barn on one of the split load RCDs, but then I wouldn't have installed the supply using T+E either. But based on the fact it's red/black I'm guessing it was a farm install, so whatever worked.

 

[Richard Burns]

The T+E that runs to the barn looks to be 16mm, from the looks of what's in the barn it used to feed the milker. In terms of capacity, we're looking at two LED bulbs, three 5ft twin fluorescent battens, tumble drier and pond pump.

Sounds like you have enough csa there!
I was a bit worried it was 2.5mm T&E and they wanted full power supply in barn for lots of equipment and then even more stuff in the outhouse.
Sounds like it is almost going to be reasonable.
Not the ideal situation but workable and compliant.