Outdoor wiring help

[Dan Carroll]

Morning all

Bit of advice please. I have a dedicated distribution circuit that was set up for a garage, that was never built, to the outside of my house. Its 6mm twin and CPC fed from a 32amp MCB. It now terminates into an outdoor double socket.

I want to extend the circuit and put some sockets around the outside of the house and one at the other end of the drive.

Now I'm wondering wether it is best to use 4mm SWA to create an A2 radial circuit. I see this as the best option as it'll give the greatest range for products to use in terms of wattage capacity. Or to use 2.5mm from and FCU at the point it comes outside and create an A3 radial.

I know that 4mm can handle everything, and i'm pretty sure that 2.5 would as well. We don't have a hot tub or any other high wattage items, but I like to be safe for any future purposes. 4mm is obviously more expensive and 2.5mm is easier to work with.

Volt drop is not a problem with the distances required.

I'm new to the industry and learning all the time.

My thoughts are, do the lot in 4mm.

 

[R-fur]

I would use 2.5 and change the 32A MCB to a 20A RCBO

 

[Spoon]

Id stick with the 4mm radial. Then its sorted for anything you want to use in future.
I'm presuming the breaker is protected by an RCD...

 

[Dan Carroll]

I would use 2.5 and change the 32A MCB to a 20A RCBO

The circuit is protected by a RCD anyway. Why would you use 2.5mm?

Id stick with the 4mm radial. Then its sorted for anything you want to use in future.
I'm presuming the breaker is protected by an RCD...

Yes protected by RCD. Thinking ahead is why I'd think of 4mm. What if I got one of those inflatable hot tubs, patio heater, plus other out door electronics.

 

[pc1966]

Certainly makes more sense to do it in 4mm given it is already sized for it.

If it is RCD protected you don't need to use SAW unless it is likely to suffer mechanical damage, but you do need to use outdoor rated cable that won't be damaged by UV light. If you want stuff that is easier to work with you have the NYY-J "Tuf-sheath" style (like SWA but minus the steel wires), or the rubber flexible HO7RN-F type. Both can be terminated easily with plastic glands for a water-resistant entry to your outdoor sockets, but for the flexible type you should use bootlace ferrules to keep the fine strands together in the screw terminals of the sockets.

 

[Dan Carroll]

Certainly makes more sense to do it in 4mm given it is already sized for it.

If it is RCD protected you don't need to use SAW unless it is likely to suffer mechanical damage, but you do need to use outdoor rated cable that won't be damaged by UV light. If you want stuff that is easier to work with you have the NYY-J "Tuf-sheath" style (like SWA but minus the steel wires), or the rubber flexible HO7RN-F type. Both can be terminated easily with plastic glands for a water-resistant entry to your outdoor sockets, but for the flexible type you should use bootlace ferrules to keep the fine strands together in the screw terminals of the sockets.

I was going to use SWA as the section under the drive will be buried.
The part around the house was going to be SWA just because I'd be buying a large roll of it, rather than 2 rolls of different type. Better value for money.