Garden Shed Electrics

[sambo88]

Hi, basically a friend of mine wants power to his shed, I think he wants a 2 lights, 2 double sockets and maybe a heater for the winter. His CU is very confusing to a novice like me but from what I can see he has the old fuseboard setup with an Ib of 60A then recently he got a new kitchen installed under the new regs where the incoming supply is split by a Henley block onto an up to date CU (RCD protected) with the kitchen circuits run from it (lights and sockets).

So am I right in thinking I can take a fused spur off one of the kitchen sockets to an outside junction box, then from there use swa cable (buried obviously) to the shed to another mini CU which is RCD protected.

Please advise on the size of the swa cable and the size of the cable for the run to the fused spur assuming I'm correct of course.

(Just note I am note undertaking this work myself I just wanted to help him gain some knowledge on the situation as well as myself)

 

[Evans Electric]

Need to know how long the cable run is to the shed .   If its miles away you will get some voltdrop so a larger cable is used. 

Coming off a spur would be fine in my book , you would have in effect , a 13A supply to the shed which is fine for a light , a plug and a 2KW heater .

 

[sambo88]

The run is no more than 20 metres and would you still have a mini CU in the shed? 2 MCB's for the lighting and power which are then RCD protected?

 

[SPECIAL LOCATION]

The run is no more than 20 metres and would you still have a mini CU in the shed? 2 MCB's for the lighting and power which are then RCD protected?

the incoming supply is split by a Henley block onto an up to date CU (RCD protected) with the kitchen circuits run from it (lights and sockets).

So am I right in thinking I can take a fused spur off one of the kitchen sockets to an outside junction box, then from there use swa cable (buried obviously) to the shed to another mini CU which is RCD protected.

Hmm..?

RCD's in series????

do you understand how they work with respect to discrimination...

little point sticking a whole shed CU in if all you got is a 13A Fused Spur supply from house...

What rating of MCB are you thinking of for your shed socket 10A? 16A?.. 

Plus a 6A for your lights...

coming from 13A Spur??

Over-engineering IMHO!!

Best just use another 3A fused spur in shed for lights!!

 

[betty swollocks]

^^ I would agree ^^ no need for another rcd unit in shed as the one in the house would protect the shed electrics, you could simply run two double sockets on the end of the swa in shed with two fused spurs after those, one for the heater 10A fuse, one for the lights 3A fuse.........

 

[steptoe]

^^

as above,

run your SWA to the shed into a metal clad double socket, makes it easier to terminate your cable, then simply link to the 2 switched fused spurs as said using conduit couplers,

depending on how you want it done you could come straight out of the fused spurs in flex using stuffing glands,

now,

who wants to bring TERRA into the conversation ?

EDIT

all of my information is specific depending on another very important variable.

 

[sambo88]

ok so what size should the swa cable be? then once terminated into the metal clad socket in the shed would the next socket be linked by conduit? and what size should the cable be for the lighting and heater? 

 

[SPECIAL LOCATION]

ok so what size should the swa cable be? then once terminated into the metal clad socket in the shed would the next socket be linked by conduit? and what size should the cable be for the lighting and heater? 

What size do you think it should be..?

what have you been taught so far on your 18month course?

http://www.talk.electricianforum.co.uk/topic/23095-currently-learning-willing-to-work-unpaid-to-gain-practical-experience/

Think in relation to Expected Loads,  Protective devices, Installation methods, Min CSA needed to carry load taking into account volt drop etc..

Have you not done any cable calcs yet????

I am guessing you are more than half way though your course from your other post?

 

[ParkySparky]

Haha nailed!!!!!

 

[m4tty]

Lets not scare him off guys we was all there once: Sam if you post up your cable calculation for what you think is correct then guys on here will help more. If you ask what size cable should I use then people may take a little pop. I'd start by doing the calcs based on 2.5mm swa and if it doesn't comply work it out based on 4mm and so on till it complies.

Look forward to your calcs

 

[sambo88]

Yes I know my cable calcs and in my opinion 2.5mm swa would be fine, maybe 4mm in case things are added at a later date but I would have to talk to my friend and clarify what he actually wants to power in the shed. I have only been taught one way of doing a garden shed supply which was from the main CU, run a cable from a MCB into a junction box with an sufficient IP rating, then from there run swa to a mini CU which would be in the shed with an RCD and two MCB's or however many you needed then use conduit to run your circuits. Like I said I'm very much a novice and just wanted to be clear on how you would run the cables so I could in theory when I'm qualified have a little more knowledge on this topic.

 

[kme]

As Albert said - there is the matter of the earthing to consider.

Further - as this is work in the garden / outside of the property - it does require notification to building regulations, as I`m sure your course will have covered?

We need more information. If you`re planning to do this yourself, to help your friend out - do we assume you have access to the necessary test equipment?

 

[sambo88]

I know under part P this work would be notifiable and no I am not planning to do this work myself, although I would like to, for my own benefit I just want to know how it would be done, I did have a fair idea from scanning these forums and I dont think I'm far off, but regards to the earthing do you mean stick a earth rod in/near the shed? 

 

[kme]

May need to - it depends on the existing system in the house, the construction & internal services that may be within the shed, and the end-of- line impedance you`d be expecting.