Garage electric to shed and summerhouse

[Patroller]

Hi all,

Its been a few years since I posted, as I am now in a new build house and basically there is almost nothing to do these days.

However, I am looking to put power to my shed and summerhouse. I know there are alot of threads on this, but I couldnt find anything specific to this particular question. Currently my SWA is on a fused switch from the dining room, where it leaves the house and pops up at the exterior of the garage, into a box, before going into the garage and serving the sockets and light. Other than the odd tool charge and a chest freezer, very little power is used out there. I want now to run electric from the garage box, with 2 x more SWA (short distances, just a few meters) to provide a socket and light in both the shed and summerhouse. Once again, infrequent and low power items. Certainly nothing power hungry.

I am aware of the limitations of the fused switch itself in terms of power, but would there be any practical reason that this wouldnt be achieveable, or at least made easier with a larger outdoor box?

Thanks for all advice.

 

[Jurassicspark]

Not a DIY suitable job. Get an electrician he should know what to do correctly.

 

[Patroller]

Not a DIY suitable job. Get an electrician he should know what to do correctly.

Thank you for your opinion.

Can anybody advise on this question, as this isnt directly addressed anywhere I can find.

 

[ericmark]

If the fused connection unit (FCU) is fed from a ring final, the first consideration is where it is on the ring final, if near centre no real problem, but if near the origin, it can cause an overload in one leg, however the risk is low.

The next is what is the shed and summer house made of? If non-conducting material, no real problem, but metal sheds can't really be connected to a TN-C-S supply.

We then need to consider volt drop, and the earth loop impedance. Again, unlikely to be a problem, but really need to know the existing loop readings to be sure.

In Wales also need registering, and the LABC chargers mean if following the rules, cheaper not to DIY.

In the main, unlikely to be a problem, but I am an electrician and have made off 1000s of SWA glands. The main problem is for some reason some outdoor boxes have 22 mm holes, not a clue why, but glands at 20 or 25 mm, so one is left trying to get a 20 mm gland to fit a 22 mm hole without leaking. So be careful when selecting the box.

 

[Patroller]

If the fused connection unit (FCU) is fed from a ring final, the first consideration is where it is on the ring final, if near centre no real problem, but if near the origin, it can cause an overload in one leg, however the risk is low.

The next is what is the shed and summer house made of? If non-conducting material, no real problem, but metal sheds can't really be connected to a TN-C-S supply.

We then need to consider volt drop, and the earth loop impedance. Again, unlikely to be a problem, but really need to know the existing loop readings to be sure.

In Wales also need registering, and the LABC chargers mean if following the rules, cheaper not to DIY.

In the main, unlikely to be a problem, but I am an electrician and have made off 1000s of SWA glands. The main problem is for some reason some outdoor boxes have 22 mm holes, not a clue why, but glands at 20 or 25 mm, so one is left trying to get a 20 mm gland to fit a 22 mm hole without leaking. So be careful when selecting the box.

Thank you for your reply, it was very helpful.

The shed and summerhouse are both wood. I am in England and everything I could find pointed towards this simply being an extension of a circuit rather than new, therefore not notifiable.

I am planning to use the Wiska 308 boxes with earthing plates, and then storm glands at each termination.

https://www.cef.co.uk/catalogue/products/4083857-85mmx85mmx51mm-polypropylene-enclosure-surface-mounting-with-lid-black-ip66

Earthing Kit for Combi 308 Enclosure (Pack of 2)

Speeds up installation of SWA cable

www.cef.co.uk

https://www.cef.co.uk/catalogue/products/4706250-storm-m20s-cable-gland-2-per-pack

Unless you or anybody recommends anything better?

 

[Murdochcat]

So OP, why not employ a competent spark to do this ?

 

[Patroller]

So OP, why not employ a competent spark to do this ?

I suppose that reply could be copied and pasted into every thread, and each thread closed. In fact, cut out the middle man and stop people posting any query.

 

[ericmark]

Competent has now been removed from BS 7671, it was above Skilled as one also looked after the safety of others. So now no such thing, although it was valid back in 2008.

My thoughts are if we point out how testing and inspecting is required that is fair enough, but to go OTT means the advice given will just be ignored.

As an industrial electrician I have worked with SWA so I see not problem, using it, there may be a problem with flame proof glands, and even I would not want to use mineral insulated, but although SWA is my bread and butter, that does not mean anyone can use it.

My aim is to instruct so done safely. My main concern is installations which will become dangerous with loss of PEN, since wood there seems to be no problem.

Next is overload, so 13 amp fuse should prevent that, and next is clearly RCD protection, but returning to the 13 amp to rupture the loop impedance needs to be low enough, and a plug in tester with loop will show if within limits.

 

[Patroller]

Competent has now been removed from BS 7671, it was above Skilled as one also looked after the safety of others. So now no such thing, although it was valid back in 2008.

My thoughts are if we point out how testing and inspecting is required that is fair enough, but to go OTT means the advice given will just be ignored.

As an industrial electrician I have worked with SWA so I see not problem, using it, there may be a problem with flame proof glands, and even I would not want to use mineral insulated, but although SWA is my bread and butter, that does not mean anyone can use it.

My aim is to instruct so done safely. My main concern is installations which will become dangerous with loss of PEN, since wood there seems to be no problem.

Next is overload, so 13 amp fuse should prevent that, and next is clearly RCD protection, but returning to the 13 amp to rupture the loop impedance needs to be low enough, and a plug in tester with loop will show if within limits.

I do appreciate that qualified people have a difficult balancing act between providing practical advice and cautioning about safety, but I appreciate you spending the time giving your feedback.