Advice needed for shed electrics

[dx90]

I want to put power into the brick built shed. It will be 6mm twin & earth from the CU to the outside/inside wall then into 4mm SWA cable and come down the wall into a waterproof outdoor socket on the wall and then out to the garage and the run is about 25m..

What side of the CU should the cable be connected, 30mA or 100mA RCD side on a TT system?

I want a couple of double sockets and a couple of lights up. What are my options in the shed to connect the 4mm SWA to?

 

[comms]

What side of the CU should the cable be connected, 30mA or 100mA RCD side on a TT system?

The 100mA side (hope it's an S type ) on a 20amp mcb then fit a cu in shed with a rcd 30mA mainswitch.
Run a spur off the house socket circuit to supply the external socket on the house wall

I want a couple of double sockets and a couple of lights up. What are my options in the shed to connect the 4mm SWA to?

Use an adaptable box to fix the gland to, then take tails through to the new cu (do this at the house end also). Set the shed up as a TT system with it's own earth rod.

 

[plugwash]

i'd think a round galv conduit box would be the neatest way to terminate the SWA if the design of the CU makes it impractical to terminate directly.

 

[Taylortwocities]

See here for things you need to consider: http://www.iee.org/Publish/WireRegs...matters_electrical_installations_outdoors.pdf

 

[dx90]

Is it not a good idea to run the SWA 4mm down the house wall and into the waterproof socket and then onto the shed, if not can you explain why?

I don't have an indoor socket to spur off of close by and the 100mA RCD is not the S version.

 

[ColJack]

you then have a socket outlet on a sub main cable.. ( assuming you are going to fit a "garage" CU in the shed.. )

 

[dx90]

I was going to fit some thing like a two way split board. It sounds like the only safe way to have the outside socket is on its own spur and not inline with the SWA cable. Is this correct?

 

[ColJack]

if you absloutely need an outside socket ( what's wrong with the old extension reel through a window i say.. ) then does it need to be at the house end? can't you put it on the wall of the shed?

couldn't you just use the socket inside the shed for that matter?

i'll assume it's for mowing the lawn or having a radio on during a barbeque or maybe the footie on a portable tv with a few beers?

 

[dx90]

No, its for the wifes water fountain at the house end. Why is it bad practice to put the socket in the SWA?

Can I still put the socket in the SWA cable but connect the SWA cable to the 30mA RCD side of the CU instead?

Or is there a good reason it needs to be connected to the 100mA RCD at the house CU?

Then just split it at the shed end for the indoor sockets and lights.

 

[ColJack]

the socket should be on the 30mA side of the board for external use..

the board should be on the 100mA side though..

you can't put a socket on a sub main cable..

 

[comms]

Ok if you put the shed on the 30mA side of house cu, in the event of a fault you've got to trog back to the house to reset it plus her indoors will be mighty miffed when the house power goes off while watching eastenders

The submain to the shed would have to go on the 30mA side if your wanting to put the socket in line, with the above problem.(a nonstarter anyway in my view)

Hence why I'd go off the 100mA side, bin the socket idea, run submain to shed, fit new cu in shed with 30mA mainswitch, set up as a TT system, run radial for shed socket from new cu, run lighting from new cu.

Then from house cu off the 30mA side run a nice 2.5mm T/E radial from a 16amp or 20amp mcb, for a shiney new socket on the wall to power the wifes waterfall.

Jobs a goodun & the lady of the house gets her waterfall & can watch eastenders in the knowledge that while you're in the shed pottering you wont cause the house rcd to trip

Edited because i missed something out.

 

[dx90]

Thanks for the explanation.
I will follow your advice and put the socket on its own 2.5 and have the garage on the 100mA side.

The only way I can run the 2.5 is down the wall on top of the plaster behind the curtin then through the wall to the socket.

Is this allowed if the 2.5 is just clipped to the wall inside?

 

[comms]

The only way I can run the 2.5 is down the wall on top of the plaster behind the curtin then through the wall to the socket.

It will be ok but why not use 16x16 trunking to enclose the cable.

 

[dx90]

Good idea, just done a search for some and it comes with adhesive on the back that will help to keep the dust down to a minimum in the room.

Thanks