Garage and Pergola power supply

[Tilecutter]

I have been asked to supply sockets and a light to a detached garage and then onto a detached Pergola with a bar behind the garage a few meters away. The customer wants a couple of 2 kw heaters in the pergola area and a couple of sockets and lights. There is a spare 45A on the Rcd protected board. I intend to run 6mm armour cable into the garage from the House c.unit into a garage 2 way board. the question is, should I run into service blocks and back out underground to pergola with the 6mm to another 3 way board, and connect the garage board into the service blocks? I cant think how else I can achieve this. Any thoughts would be appreciated. There is another spare on the house CU but on the same Rcd at the moment. I was trying to avoid running two armour cables out and up the garden.

 

[HandySparks]

I don't have a problem using the supply terminals of the main switch in the board to daisy chain the supply cable. Just done it with a 10mm² SWA. It makes a perfectly sound connection to 7 strand cables in a rising clamp terminal.

 

[Deleted member 9648]

just run the SWA to the pergola from a spare way in the garage DB.....or as above loop the second SWA straight out of the incomer terminals in the garage DB

 

[tomspark93]

Why not just use a larger board in the garage and take all final circuits from that? Buying a 6 way board would be cheaper than buying a 2 way and a 3 way and will take less time to install. Ideally the rcd protection would be local to the garage side of the installation but i appreciate you only have a spare way on the RCD side of the main board. How far away is the pergola from the garage?

 

[telectrix]

i'd split the tails in the house then into a 40A switch fuse, then SWA to 6 way garage CU. then RCBOs fitted where required.

 

[tomspark93]

i'd split the tails in the house then into a 40A switch fuse, then SWA to 6 way garage CU. then RCBOs fitted where required.

I'd go with this option ideally as well.

 

[Midwest]

I don't have a problem using the supply terminals of the main switch in the board to daisy chain the supply cable. Just done it with a 10mm² SWA. It makes a perfectly sound connection to 7 strand cables in a rising clamp terminal.

Not quite sure I agree with that, if I'm correct in thinking your suggesting putting two cables into one terminal? Whilst I realise that that's done for smaller terminals, i.e. 32amp mcb with two wires from an RFC, I wouldn't do something similar with 16/25mm tails and another similar cable. Not sure even with cage clamp terminals that both cables would be suitably terminated. My opinion.

 

[HandySparks]

Not quite sure I agree with that, if I'm correct in thinking your suggesting putting two cables into one terminal? Whilst I realise that that's done for smaller terminals, i.e. 32amp mcb with two wires from an RFC, I wouldn't do something similar with 16/25mm tails and another similar cable. Not sure even with cage clamp terminals that both cables would be suitably terminated. My opinion.

I agree. I'd think twice about putting another cable in a terminal with 16 or 25mm² tails because the strands are so stiff (if 7 strand).

However, I thought that the OP was asking about bringing a 6mm² SWA into a board and then onwards to another one. If they're the usual 7 strand, they'll work just fine in a rising clamp terminal of a main switch designed for cable up to 25 or 35mm².

 

[Tilecutter]

Why not just use a larger board in the garage and take all final circuits from that? Buying a 6 way board would be cheaper than buying a 2 way and a 3 way and will take less time to install. Ideally the rcd protection would be local to the garage side of the installation but i appreciate you only have a spare way on the RCD side of the main board. How far away is the pergola from the garage?

The Pergola is about 3 mtrs on up the garden from the back of the garage. So I would need to run SWA underground and up to the pergola from the garage so I would need some sort of distribution for Sockets Heaters ansd lights in the pergola.

 

[Tilecutter]

i'd split the tails in the house then into a 40A switch fuse, then SWA to 6 way garage CU. then RCBOs fitted where required.

Im not following you with that idea. The SWA needs RCD protection does it not?

 

[HandySparks]

Im not following you with that idea. The SWA needs RCD protection does it not?

No. (Unless required for fault protection on a TT supply.)

 

[HandySparks]

The Pergola is about 3 mtrs on up the garden from the back of the garage. So I would need to run SWA underground and up to the pergola from the garage so I would need some sort of distribution for Sockets Heaters ansd lights in the pergola.

If it's only 3m, keep the board in the nice dry garage and run separate final circuits to the various loads in the pergola.

Why not put in a length of good sized ducting and run your swa final circuits in that. If you want to add another one later it'll be easy.

 

[davesparks]

Im not following you with that idea. The SWA needs RCD protection does it not?

Why does it need RCD protection?

You've designed it with RCD protection so presumably you have made a conscious decision that it is required? Not just guessed?

 

[davesparks]

The Pergola is about 3 mtrs on up the garden from the back of the garage. So I would need to run SWA underground and up to the pergola from the garage so I would need some sort of distribution for Sockets Heaters ansd lights in the pergola.

Why not run a couple of circuits out from the garage board?

 

[LankyWill]

You have overlooked bonding, is it a PME supply? If so run a 10mm earth as well and then you can bond the water services at the bar. Surely a 10mm swa would be better for future alterations, unless 6mm has proved adequate from your calcs? Id got with one boards as well.