Garden Office Power Supply

[musashi79uk]

I'm looking at running a power supply to a garden office for 8 double sockets, an internal lighting circuit and an external lighting circuit.
In my home consumer unit (house was fully rewired with new CU in 2020), I have a spare B40 MCB.
Am I able to go from the B40 with 6mm T&E to 3 Core 6mm SWA (connected with Wago connectors and gland connector in IP66 wall box) buried underground to the office where that will be connected to 6mm T&E inside another IP66 wall box with gland kit, through the office wall and then go to an internal 3 way Axiom CU?
From the 3 way Axiom CU in the office, I was going to use the B32 for the sockets ring main, the B16 for the 6 internal 4w spot lights and the B6 for the external light.
Am I able to do that from the B40 MCB in the house CU?

 

[flameport]

Am I able to go from the B40 with 6mm T&E to 3 Core 6mm SWA (connected with Wago connectors and gland connector in IP66 wall box) buried underground to the office where that will be connected to 6mm T&E inside another IP66 wall box with gland kit, through the office wall and then go to an internal 3 way Axiom CU?

That could be done, but a much easier option is to use SWA throughout, and not bother with any additional connections or boxes.

From the 3 way Axiom CU in the office, I was going to use the B32 for the sockets ring main, the B16 for the 6 internal 4w spot lights and the B6 for the external light.

Could also be done, but a ring circuit for a single room is pointless, a few LED lights does not need a 16A circuit, and the outside light doesn't need it's own circuit either.

All of this requires RCD protection, and it's notifiable work.

 

[musashi79uk]

Could also be done, but a ring circuit for a single room is pointless, a few LED lights does not need a 16A circuit, and the outside light doesn't need it's own circuit either.

All of this requires RCD protection, and it's notifiable work.

The house CU is a 10-way one split into 2 lots of 5 MCBs. Each lot of 5 has a RCD on it. Is that what you mean by "requires RCD protection"?
As for the office CU (also having RCD protection), would a 2 way one be better and run a radial circuit off it for the sockets and a single lighting circuit for the indoor and outdoor lighting?