Wiring a summer house

[kyleshweet]

Hi, I was hoping that someone could confirm or correct what i intend to do do with suppling a summer house with power.

From the Main C/U in the house i will take 4.0mm2 SWA off a 32A CB up into the roof and along to the corner of the house. Now this is what i am unsure of - There a fixed awning between the house and summer house, i would like to run the the SWA along underneath, clipped to the awning and into the summerhouse. I will then take the SWA into a MK IP65 Garage C/Unit 40A 30mA RCD+1x6A 1x16A SP CB. From that i will have a switch to strip light on the 6A CB & a ring main with 4 double sockets and a spur to a outdoor socket on the 16A CB.

I am fully aware of part P compliance and that it is notifiable work.
I have attached a pic of the proposed
Thank you

Untitled

• kyleshweet
• 13 Aug 2008
• 1

Untitled

• kyleshweet
• 13 Aug 2008
• 1

 

[Pensdown]

How long is the run. 4mm may be a bit tight with volt drop. 6mm is not that much more expensive and will give you some spare capacity.

Can you post a picture of the "awning" that you propose clipping to?

 

[kyleshweet]

The run is only about 15m from C/U to C/U. The summerhouse will be replacing an old garage so the awning has been taken down for the mean time. The awning is constructed from 2 x 3 inch timber cross sections and a corrugated plastic roof. It will be secured to the house and to the summerhouse when it goes up in about 2 weeks.

 

[Pensdown]

For a sub-main design load of 32amps you will just get away with 4mm but it will only leave you a volt drop of 1% for your final sub-circuits. I would still recommend that you install 6mm.

Without seeing it, it's a bit hard to say whether your "awning" is suitable to clip to. It would need to be sound but leaving that aside, in a few years you may decide you don't want the awning any more, then what happens?

Is there no other route?

 

[kyleshweet]

I think that i will take your advice and use 6mm SWA, i would take a picture of the awning but as i said it has been taken down. Once the summerhouse has been erected, i will be constructing a new awning to replace the old one. It will be sound. There was cable on the old awning that supplied the garage but was not done correctly as it was 2.5mm T&E only! So this is why i was checking whether i could run it in the same way but correctly.
The only other way is to run the cable down the exterior of the house and dig a trench through the concrete - which i am trying to avoid.

 

[Pensdown]

If you do decide to clip to the awning (assuming it's sound I'm not aware of any regs to say you can't) leave a small loop of cable where it goes into the awning and where it come off.

The allows for a bit of movement without damaging the cable.

I don't know if you've played with SWA cable before but if not, there are some good tips on glanding it off in the Wiki section.

 

[kyleshweet]

Thanks for the advice. I have worked a bit with SWA, i am training to become an electrician, i have recently completed City & Guilds 2330 17th addition and a part p domestic installers course. So this will be my first real (in the field) installation!

 

[Cremeegg]

Nice simple job to show your scheme assessor - he/she should find plenty there to test you on - apart from how deep the trench should be when you bury cable! Sounds more like a permanent lean to/car port than an awning so wouldn't see any problem clipping to it. Always worthwhile oversizing your cable to cater for future loads - like the hot tub in your summerhouse.