Shed wiring, cables in the walls or in conduit?

[m1ke_a]

Chaps

My new shed is up and I'm now working out the electrics for it.

I'm looking at two external double sockets (for the mower etc) eight doubles inside and a separate light circuit. Might split the power sockets in to two radial circuits for ultimate redundancy.

I'll be getting a sparks in to OK the final spec and shopping list beforehand and to commission the system.

The shed framing is 40mm and I've got loads of 25mm Celotex board to fit for insulation before boarding over. Trouble is I can't decide whether to just run the T/E cable through the framing or fit conduit on top of the interior boarding? The Celotex is going to take a fair bit of the available depth so the cable would be pretty close to the inner panelling once fitted.

Obviously conduit is going to add to the cost but if you're going to do it properly etc etc.

What do we think?

 

[Phil Pascoe]

Why not surface wire it- it's a shed, it hasn't got to be pretty. It allows easy access for additions, and it's visible so you're not likely to put a nail through it. My workshop/garage is 18' x 20' and I've 25 doubles; at any given time, half of them are inaccessible because of shelving, sheet material etc., so I would say put even more in. Use cheap sockets-half of them will have stuff plugged in permanently, and if one ever fails replace it with something a bit better. By the time you plug in the heater, radio , phone, tv, dvd, freeview box, hifi and beer fridge you won't have many left.

 

[m1ke_a]

........... By the time you plug in the heater, radio , phone, tv, dvd, freeview box, hifi and beer fridge you won't have many left.

:lol:

I think my missus might have something to say about that little lot! (hammer)

Surface mounting makes sense from a visibility point of view. Metal or plastic conduit?

 

[jasonB]

I would avoid " cheap sockets" go for metal clad that way if you are swinging bits of timber around and you cloat a socket its not going to smash. 20mm Plastic conduit will be fine with teh metal boxes.

J

 

[Gromit62]

When I kitted out the electric’s in my shed although its only 12 x 8 I put 2 extra double sockets in the apex on the roof, surprising how convenient it is to reach up and plug portable power tools in and not stretch over things, just a thought for you m1ke_a.
Geoff.

 

[bobscarle]

When I wired my shed I ran the cables in the walls. I now wish I hadn't. I could do with moving a one and adding a new one, not an easy job. If I were doing it again I would certainly go for surface mounted conduit.

Bob

 

[Shultzy]

I have the cables in the walls. I put a loop of cable in each bay, so if I need another socket I just need to cut a hole pull the loop out and connect the socket. I also have a socket on each ceiling joists with a coil of cable to plug into each portable tool. I also switched each lighting tube so I don't have unnecessary lights on. Remember to put an auto outside light next to the door to aid locking up in the dark.

 

[m1ke_a]

Thanks for the replies fellas

Gromit, I was planning on a couple of sockets at eaves height for such occasions.

Shultzy, Front door to the shed will have a PIR lamp and the back door will be switched on internally. - Not planning on using that door that often.

The shed is 16 X 12 and I was thinking three 4 ft fluorescent tubes for interior lighting. Would it be worth doing extra?

 

[andersonec]

Cables in black Ega Tube (conduit) and metal boxes is the way to go, if you put cables in the framing and at a later date you decide to put up some shelving you could hit the cable plus as it has said before adding sockets, spurs etc will be easily done. I think you'll find plastic boxes in a workshop / shed / garage etc is a no no, May cost a few quid extra now but it will be safer and save you money in the future.

 

[jasonB]

I think you will want more light than that. My 16x16 workshop has four double 5 ft fittings and an extra single 5ft above the bench, my 16x 8 shed has four 5ft singles and a couple of angle poise where needed.

J

 

[dedee]

If it is not too late I would recommend putting a socket or two in the floor. In my 3m x 3m workshop I have to have everything on wheels and pull them out into the centre of the workshop, being able to plug them into the floor saves having to trail leads across the floor.

Cheers

Andy

 

[plug]

This is how i did mine
workshop-electrics-question-t23414.html

 

[MrA]

I installed a 2.5mm ring circuit in 20mm PVC conduit with metal double sockets run from consumer unit. I only installed 10 doubles, I never thought to install 25! :shock:

 

[dedee]

think carefully about the conduit runs

don't do this

this is much better

I spent weeks thinking about and it took me about 2 mins to realise my mistake.

Andy

 

[brianhabby]

Definitely agree, whatever you do put the wiring on the surface for future alterations. Also another plus for more than you think you will ever need. My preference is to use conduit, and unlike others on here, I have broken the plastic ones.

Double Switched Metal Clad from Screwfix £4.43, Toolstation £4.12

regards

Brian

 

[Phil Pascoe]

I haven't broken a plastic socket yet, and if I do I've got plenty of spares- they were 90p each.

 

[jasonB]

think carefully about the conduit runs

this is much better

Andy

Even better is to run the conduit straight into the side of the box and out the other, saves all those "Tee" boxes.

J

 

[m1ke_a]

Thanks again for the thoughts.

I reckon I'll hit £600 for parts but I'd rather overspec things. 6mm SWA to the shed, 4mm T/E inside in 25mm plastic conduit to metal clad boxes.

I'll probably split the sockets into two ring circuits and the bulk of them will be at waist height with 4 or so up at eaves height.

JasonB; thanks for the comment about lighting. I was going with double fittings and there isn't a monstrous cost difference between 4 and 5 ft units.

 

[Wildman]

When I wired my shed I ran the cables in the walls. I now wish I hadn't. I could do with moving a one and adding a new one, not an easy job. If I were doing it again I would certainly go for surface mounted conduit.

Bob

take one off the wall and add a surface mount spur to it job done. wire in walls is impossible to check for rat/mouse chewing, first indication is usually whe then shed burns down.

 

[jasonB]

4mm is a bit OTT, you may even have a job getting two wires into the terminals in the sockets. 2.5mm should be fine.

J