SPLIT:wiring up a detached shed

[russellh]

Hi there, i have similar project on the go - wiring up a detached shed with a double socket to use as a workshop. i have a couple of questions: i already have outside power , swa cable running down a wall to a rcd ip56 socket, from which the cable runs further down the garden to another plain ip56 socket. the shed is only another few metres on from this socket

do i need part p if i already have outside power, as all im doing is extending it? if i do, it may be quicker to get a sparky in

if not, id enjoy doing it myself. i guess the first point is can i just run another spur off this final socket? i can punch out a 20mm hole on the final socket then shld i use SWA cable and a gland or conduit as well as it will be going under some turf to get to the shed. Finally when i get to the shed, whats the best way of gaining entry?

thx in advance
_______________________________
Lynda, moderator

Your post has been split, please see forum rule 20

 

[Steve]

You should get away with it. However, I suspect it IS notifiable.

I am curious - why one RCD socket and one non-RCD?

Is the supply RCD protected? If yes, you dont need any RCD sockets. If no, BOTH sockets should be RCD type.

 

[russellh]

thanks crafty
i didnt install it but know the the supply isnt RCD protected, so i guess they shld both be RCD. im rather an amateur but wldnt the first socket protect the 2nd if the 2nd is a spur off it? maybe this was their foggy thinking too!

 

[Steve]

thanks crafty
i didnt install it but know the the supply isnt RCD protected, so i guess they shld both be RCD. im rather an amateur but wldnt the first socket protect the 2nd if the 2nd is a spur off it? maybe this was their foggy thinking too!

Nope. The RCD protection on a socket is only afforded to its own sockets and does not extend onto any circuit it is wired to.

Best way to enter shed is directly up from below the shed through the floor. If this is impractical then go up the side of the shed into a round metal conduit box, then through the wall.

 

[davy_owen_88]

Unless the supply cable to those outdoor sockets is extremely beefy, I don't fancy your chances of powering a workshop from it. Perhaps if you explain what sort of 'workshop' we might be able to offer better advice.

 

[russellh]

thx i agree its rather odd to have the 2nd socket unprotected, especially as its the one i use!!

i havent done the loading calcs yet but im only looking to run one or two minor power tools (rechargeable items), the cable looks quite beefy but ill have to check what it is. the shed is abt 15m from the CU and abt 3m from the last outdoor socket, maybe 7m from the RCD socket - im thinking 4mm SWA wld cover it

wld it help to make the shed socket RCD? i can access it no prob from the floor, does one have to conduit SWA over the last few metres under the grass or not needed?

 

[luminaire]

i already have outside power , swa cable running down a wall to a rcd ip56 socket, from which the cable runs further down the garden to another plain ip56 socket. the shed is only another few metres on from this socket

Where has the supply originated from?
Does it come from the CU? In which case, what size is the OPD?
Or was it taken off an internal socket?
Also what is the earthing arrangement?

 

[russellh]

hi luminare
im afraid i dont have all the answers. ive been told by a sparky that the outdoor power doesnt have a separate CU and that the RCD sockets were the bare mimimum these days. its hard to trace the SWA but the assumption is that is comes from the main CU (also earth supply) - im confident its not off a socket

the wiring clearly isnt great but for such a small extension im happy to wear it and im just trying to make sure i do the best possible

sorry to be ignorant - OPD?

thx for help

 

[luminaire]

You need to know what load it's going to take. From that and the cable length what size cable you'll need. In other words will you need bigger than what you've got at present.
Then the size of the MCB for that circuit in your CU.
I.e. the overcurrent protection device (OPD).
If you decide on RCD in the garage, you'll need another RCD skt outside.
If not, you could have a single pole RCBO or changing your CU.
Your best bet is to talk it through with your electrician.

 

[russellh]

thx for your help luminare