Power to a shed and summerhouse

[Billy Boswell]

Hi,

I have read quite a few posts on here about this already, and I need to know what size SWA I will need and what size RCD and MCB. which seems to depend on load and distance.

I want run a spur from an internal socket using SWA, which will run 25m to the shed being part buried and part tacked to decking. I will have a normal 60w light and 2 double sockets in the shed, nomal usage (lawn mower, diy tools etc).

I will also run a further 25m length of SWA from the shed to the summerhouse, which will have 1 light 60w and 1 double socket, low usage (radio, cd player).

Will I just need a rcd and mcb in the shed? and what size SWA I was thinking 1.5mm 3 core.

Billy

 

[breezer]

as you said I have read quite a few posts on here about this already you should also notice what you propose is against regulations (suring off a spur)

read about it again, and you will find the correct solution and the answer to your question, try looking for "power to gargage or power to out building"

 

[Billy Boswell]

Breezer,

There is already a spur off a socket going to a double light switch, (was there when we bought the house) one switch is for 2 outside spot lights and the other was for a garden pond pump via a plug socket. The pump is now no more, and I intended to put one of those plates with a 13amp fuse in and thats what i would connect the SWA to.

I thought that would have been ok, I would have to take up the flooring to get to a cable which goes to the fuse box.

billy

 

[breezer]

just because "it was there" doesnt make it safe

there is only one way to do a job, and that is properly, the effort involved is off set by the fact you know it is the right thing to do, and it is correct, it may also prevent some one from being electrocuted

 

[Billy Boswell]

Ok, I'll connect the SWA to the fuse box.

Will I just need a rcd and mcb in the shed? and what size SWA I was thinking 1.5mm 3 core

Billy

 

[breezer]

yes. but 2.5mm would be better suited

 

[Big_Spark]

He should do a calculation on the probable loading of the first pat of the circuit, from the House to the shed, taking into acocunt the summer house loading.

When he knows the maxmum it will be, then calculate the volt drop on this section of cable, he may (probably not) need to go to 4mm SWA to comply.

 

[Billy Boswell]

what type of glands will I need for this cable http://www.screwfix.com/app/sfd/cat/pro.jsp;jsessionid=QFWN1FJWAZGORCJO2C3CIIQ?id=19322&ts=61923

one end of the cable will be inside the shed and the other inside the house.

Billy

 

[ban-all-sheds]

You'll need a BW gland indoors, and I'd suggest a CW in the shed, as sheds aren't always the most watertight of buildings. Given that they come in packs of 2, buy CW ones. Search on Screwfix for 'gland'.

You'll also need metal boxes / CUs to terminate in - plastic probably won't take the stresses.

 

[securespark]

I would use 2 rcds - one at the house end to protect the cable, and one in the shed to protect the circuits.

 

[Big_Spark]

I just looked at the link to the cable on screwfix...Blooming heck is all I can say..talk about profiteering!!

£21.99 for 25m of 3x2.5 SWA!! Someone tried to charge me that I would punch them in the face!!

 

[securespark]

That includes the dreaded, though, Jim.

Denmans offers it at 70p/m = 20.56 for 25m inc vat
TLC offers it at 95p/m = 27.91 for 25m inc vat

What do you get it for?

 

[dingbat]

Denmans offers it at 70p/m = 20.56 for 25m inc vat


What do you get it for?

OOI the last 2.5 sqmm 3-core swa I got from my local Denmans came in at under 50p/m, but it was that month's 'special'.

 

[kendor]

I would use 2 rcds - one at the house end to protect the cable, and one in the shed to protect the circuits.

Wouldn't this be an issue with discrimination?

 

[Big_Spark]

Simon, we only buy 100mtr drums of it, so I suppose that helps, but the most we have paid was less than 40p a meter.

I checked some invoices for recent purchases, and we are paying E&E 34p/mtr for 3C2.5, 28p/mtr for 2C2.5, 41p/myr for 4C2.5, 52p/mtr for 2C4.0, 66p/mtr for 3C4.0, 87p/mtr for 3C6.0

But we do buy about 1000mtrs of SWA a week, not to mention all the other materials.


Kendor, the only problem will be encountered if the RCD's are not rated so as not to cause problems. IE..in the House 50A 300mA, in the shed, 40A 30mA, the max current rating is only an example, this should be determined in the usual way, but the trip ratings for the devices should be along thos lines to use two together.