Taking power to a Shed / Garage.

[sweeneyuk]

After some advice from the experienced sparks out there.

I have built a concrete base at the end of my garden ready for a 15' x 10' summerhouse to go on.

I need to take power to it for s/o & lighting.

The shed is approx 12m from nearest part of house which is a kitchen extension.

Need to take pwr from main CU under stairs in the house, best route i can see is to take it up to my loft then out through eaves, down exterior wall around eaves on extension & along concrete fence posts.
My extension roof cavity doesnt line up with floor cavity of house so running under floorboards into extension roof cavity is out.

Questions.

1. should i run 10mm up to the loft & into an adaptable box by the eaves, run 10mm swa from the box out through eaves along walls & through black pvc conduit attached to fence posts?
then Run it straight in to a metal clad CU inside shed.

2. Could i just run 10mm t&e all the way using blk pvc conduit for the exterior run?

3. Should i use a 40A rcbo at main CU in house with a 32amcb ring in the shed or just a 20a mcb radial for s/o's? will use a 6Amcb cct for lighting.

Want to avoid burying anything as i have a patio in the way.
Looking for the easiest most cost effective way to take pwr to shed.

Have a load of 10mm left over which i'm hoping to use.

Did consider a fused spur from a s/o on kitchen ring in the extension but as this will limit me to 13a in total have now ruled it out.

Is there an easier way?

any help appreciated.

 

[sweeneyuk]

Thanks for all the good advice.

Will def add some kind of batton along fence posts to attach the swa cleats to.

Summerhouse is all wood construction inc window frames so assume i'm good to carry through the cpc?

Should i use 3 core swa & use 1 conductor as earth, earthing the armour at 1 end only?

Will come off the non rcd side on home fuse board using a 40a mcb as suggested then rcbo the ccts inside the shed CU.

As i have 10mm T&E left over will prob run that up to eaves then through adaptable box into swa. will take swa all the way into metal clad CU in shed.

Now making relatively tight bends using 10mm swa, any advice on best methods?

Also should i use 3 core

 

[Deleted member 26818]

I wouldn't bother with 3core. Just use the armour as the CPC.

 

[mike2790]

the way i would do it is to take some 10mm tails into an enclosure with a 100mA RCD and a 40A breaker, come out of the breaker with the 10mm twin you have lying around into an adaptable box, i would definately use 10mm SWA for outside earthed at both ends (personally i like to use 3 core and use the remaining core for earth but the armoring would be okay), into a metal clad CU in the shed, 30mA rcd, 32A ring or 20A radial (wired in 2.5mm) for sockets and a 6A circuit for the lighting. job done.

 

[Wiredspark]

Earthing the armour at one end only? er why? For the little extra cost of a 3 core, yes I'd use 3 core. A little extra protection is NEVER a bad thing.

edit: If you are only gonna earth at one end, just how are you gonna terminate at the other???

 

[telectrix]

Earthing the armour at one end only? er why? For the little extra cost of a 3 core, yes I'd use 3 core. A little extra protection is NEVER a bad thing.

edit: If you are only gonna earth at one end, just how are you gonna terminate at the other???

plastic SWA gland?

 

[Wiredspark]

never thought of that

 

[sweeneyuk]

the way i would do it is to take some 10mm tails into an enclosure with a 100mA RCD and a 40A breaker, come out of the breaker with the 10mm twin you have lying around into an adaptable box, i would definately use 10mm SWA for outside earthed at both ends (personally i like to use 3 core and use the remaining core for earth but the armoring would be okay), into a metal clad CU in the shed, 30mA rcd, 32A ring or 20A radial (wired in 2.5mm) for sockets and a 6A circuit for the lighting. job done.

I assume you would use a 100a tails connector block to run 10mm tails into seperate 100ma rcd enclosure?

Only reason i suggested earthing at 1 end is i've read that using the core & armour will give a parallel earth path, not sure on how adversely this will affect results though?

 

[Wiredspark]

I assume you would use a 100a tails connector block to run 10mm tails into seperate 100ma rcd enclosure?

Only reason i suggested earthing at 1 end is i've read that using the core & armour will give a parallel earth path, not sure on how adversely this will affect results though?

why not use this

 

[Deleted member 26818]

There's nothing wrong with having parallel earth paths in this particular case.
In some instances, with sensitive equipment, such as guitar amplifiers and perhaps some inverters, there can be problems with earth noise.

 

[sweeneyuk]

Does the space underneath the kitchen units behind the kickpanel constitute a viable enclosure to run cable?

Only ask as it would be the most direct route to get cable to outside wall of extension & save a lot of cable.

I doubt i will be able to reach far enough to clip it direct the the rear wall under there but maybe it could be run through some flexible conduit?