Supply setup using enclosures - is this ok?

[newb]

Running power to my shed using 4mm SWA - was going to use the setup below and would like to know if it is ok.
I will take the supply to the 1st enclosure from the load side of the CU switch (no spare ways) - this will supply an RCD (30ma 60A) and feed a 32A MCB.
SWA to 2nd enclosure supplying a 20A and 6A MCB - neutrals connected into chic block.
Earths will be in choc blocks inside enclosures (inc earths from banjos etc)

Is it ok to connect the neutrals and earths this way?

Many thanks

 

[Qedelec]

So if your down the shed in the winter and you trip the RCD, you have to stumble back up the garden in the dark to reset the supply, you might like to have the RCD at the shed end.

 

[newb]

So if your down the shed in the winter and you trip the RCD, you have to stumble back up the garden in the dark to reset the supply, you might like to have the RCD at the shed end.

I had thought of that but maybe wanted to protect the SWA with the RCD as well as circuits in the shed - this may be unnecessary and would like opinions

 

[Steve]

The SWA doesn't need RCD protection. If someone puts a shovel through it, the MCB at the house will trip first (shovel will short live to neutral and earthed sheath and cause huge current to flow, thus cutting off the supply, this is how SWA works)

Best way to do this is take supply from an MCB at the house (if theres no spare ways, have an electrician split the meter tails and fit a small 4 way enclosure (for future needs too). Then run the SWA from an MCB in this new enclosure to the shed, where there will be an RCD and 2 MCBs in a consumer unit.

Dont forget to notify the local council under part p.

Dont connect the SWA into the isolator of the house CU - it isn't protected.

 

[RF Lighting]

There is no need to protect the SWA with the RCD. The MCB will provide all the protection that the cable requires.
You should not tap the new CU off the main switch in the existing CU. You should install a henly block in the tails feeding the existing CU, and take the new tails from this too. Also it would be a good idea to fit a 3 way CU at the shed end for future expansion (you never know!)

 

[Steve]

Also it would be a good idea to fit a 3 way CU at the shed end for future expansion (you never know!)

in which case, use 6mm or 10mm SWA - you never know when you'll need a hot tub / kiln / particle accellerator in your shed.

 

[newb]

Thanks guys
Is using choc block acceptable (suitably rated) to join earths in the enclosure?

 

[RF Lighting]

Why not use a one way and a three way consumer unit? These will have proper earth and neutral bars fitted in them, and usually works out cheaper than buying the enclosure and the main swich / RCD seperatly

1 way with main switch
5 way with RCD

(couldn't find a 3 way metal clad)

 

[newb]

Why not use a one way and a three way consumer unit? These will have proper earth and neutral bars fitted in them, and usually works out cheaper than buying the enclosure and the main swich / RCD seperatly

1 way with main switch
5 way with RCD

(couldn't find a 3 way metal clad)

I already have the enclosures and breakers - just need to buy a RCD
Was going to fix connector to back of box for earth/neutrals as needed

 

[RF Lighting]

Strip connectors will be fine providing they are apropriatly rated.