Electrical advice - Running power from a weather box to a shed.

NeilF · 4 Mar 2022 at 11:45

I'd like to do this myself if possible, but want to ensure (being a total noob) if I can

I have a weatherbox under some decking in the garden with plug sockets in. This is on its own circuit into the fuse box with its own isolator switch too.

Across the garden I have a new shed. I'd like to run mains power from the weatherbox to the shed simply for a light and some plug sockets (just for lower power stuff like recharging things. ie: Not bar heaters.)

I have some 12-13mm thick armoured back. 3 core (black, brown, grey).

Could I:-
- Feed the armoured cable into the weatherbox and wire its 3 cores (black, brown, grey) into say a 13A plug, and plug that into the plug board.
- Run that armoured cable across the garden, and into the back of the shed.
- Terminate that armoured cable into a simple knockout terminator box using a gland kit.
- Then run the live, neutral and earth (black, brown and grey) feeds off to a simple switched light and also off to say a four way plug socket?

Note: The above would not be using the armour in the cable as an earth.

Is the above electrical noob nightmare territory, or is it, as I'm seeing it simply running a long extension lead off a plug (in the weather box) and running a light and another plug board off it.

Ultimately, do I do this something like above, or spend three figures getting an electrician in?

builder22 · 4 Mar 2022 at 12:22

don't think the SWA would fit in a plug properly...

someone will be along to tell you exactly but if you're going to the bother of running the cable would be better to have it terminated properly rather than a plug...

NeilF · 4 Mar 2022 at 12:25

There's already a plug board in the weather box, so should be easy to feed the inner three cores of the armoured cable into a 13A plug?

builder22 · 4 Mar 2022 at 12:37

it might 'work' but I don't think it's 'right'...the armor should be earthed on the swa too

I'm sure one of the electricians on here will reply...

a1ex2001 · 4 Mar 2022 at 13:50

What you are suggesting will work but isn't right! Getting the SWA into a standard plug will be a pain and as above the armour should be earthed correctly and running your shed of what is essentially a long extension lead is naff.

NeilF · 4 Mar 2022 at 13:59

a1ex2001 said:
What you are suggesting will work but isn't right! Getting the SWA into a standard plug will be a pain and as above the armour should be earthed correctly and running your shed of what is essentially a long extension lead is naff.

Understood, but how is it naff if it 100% achieves the goals, safetly?

Mercenary Keyboard Warrior · 4 Mar 2022 at 14:32

Does the socket have a spare knockout? Normally they have like 6 or so

If so wire the SWA into the same connectors inside, its already properly connected up and its just an extension, you can then earth to the sheath via proper SWA connectors and glands
When you get to the shed wire into a socket (or 2, if so normal twin and earth between them) use metal sockets/switches etc and earth them properly as well, then take a spur from that to the light but make sure you via fuse drop that down to a 3/5amp

This is basically exactly how my garden is wired as designed by my works electrical manager. Mine is all limited to 13A but have never tripped it.

Technically however you shouldnt do it as its classified as outside work

NeilF · 4 Mar 2022 at 14:59

OK... I'm going to get an electrician on the case

Ta

K.C. Leblanc · 5 Mar 2022 at 15:15

SWA as into a plug isn't going to work well. Even if it's not being used as an earth the armouring should still be earthed.

Also the thickness of the cable you've quoted in it's external diameter. To be suitable it will need to have conductors with a cross sectional area of at least 1.5 mm (ideally 2.5 mm, maybe more depending on length).

What are you planning to run from the plug board in the shed?

NeilF · 5 Mar 2022 at 15:18

K.C. Leblanc said:
SWA as into a plug isn't going to work well. Even if it's not being used as an earth the armouring should still be earthed.

Also the thickness of the cable you've quoted in it's external diameter. To be suitable it will need to have conductors with a cross sectional area of at least 1.5 mm (ideally 2.5 mm, maybe more depending on length).

What are you planning to run from the plug board in the shed?

Electrician visited today - Coming to do the job (properly) next week

The shed will just have really lower power stuff in it. Recharging stuff. Xmas xlights. Maybe a ring security cam.