CU in the summerhouse

[didster]

I need to put power in the summer house ...
I have an RCD Shed unit in the shed (of course) and intend to do the following ..
Replace the existing shed unit with a new CU with 80A 30ma RCD and 6A, 16A (lights and sockets) and 20A MCB for the summerhouse ..
4mm SWA to the summerhouse and a new Mainswitch CU with 6A and 16A MCBs for lights and radial circuit to 2 sockets ...
Am i right in thinking that if i put an RCD in the summerhouse unit it will conflict with the RCD in the shed unit .. the RCD in the shed unit is sufficient to protect all the on-going circuits in both the shed and summerhouse ..
cable run is only 6m or so ..
Thanks in advance ..

 

[ban-all-sheds]

You're right about the RCD.

Do you know that this work is notifiable?

How do you plan to test your new cables and circuits to confirm they're safe?

Do you know how to route the SWA to the summerhouse?

Do you plan to gland the SWA directly into the CUs?

 

[didster]

Thanks for the quick reply ..
I do know this is notifiable .. I intend to get it signed off but I enjoy doing these sort of projects myself before getting them signed off ...
I will be testing with a plug in tester to test earth continuity ..
The SWA is already run .. buried to 1ft and clamped to termination at either end ..
I intend to gland both ends but for neatness not additional earthing purposes .. the existing shed CU has it's own earth to a rod and i shall be bonding the SWA to that at the start of the run ..

 

[ban-all-sheds]

I do know this is notifiable .. I intend to get it signed off but I enjoy doing these sort of projects myself before getting them signed off ...

It doesn't work like that - you should read this: //www.diynot.com/wiki/electrics:part-p

I will be testing with a plug in tester to test earth continuity ..

Not adequate - you should read this: http://www.tlc-direct.co.uk/Book/8.1.1.htm

The SWA is already run .. buried to 1ft

Not deep enough.

And did you bed it properly, and put warning tape above?

Did the electrician you hope will "sign it off" specify the routing of the cable and inspect and approve it before you covered it up?

and clamped to termination at either end ..
I intend to gland both ends but for neatness not additional earthing purposes ..

The only way to terminate SWA is with a proper gland - what do you mean by "clamped to termination at either end"? The armour must be earthed, even if you aren't relying on it for the cpc. You should read this: //www.diynot.com/wiki/electrics:swa-gland

the existing shed CU has it's own earth to a rod and i shall be bonding the SWA to that at the start of the run ..

Why?

What type of supply do you have? ( //www.diynot.com/wiki/electrics:earthing_supply_types_and_bonding:earthing_arrangements )