Running a new SWA to supply a shed

H

Helm-Electric

Running a 4mm SWA to the shed, approx distance is 20m. Earthing is PME.

I plan to run the 4mm SWA out from the wall of the house and cleat it along the side until it reaches the back of the house. From there the cable will go to ground at a depth of 450mm all the way to the shed. I plan to fit a 2 way CU for lights and a double socket within the SHED. The SWA will be protected by 30mA RCD and MCCB at the CU within the house. Total load shall not exceed 2kW. The installation will be inspected and tested by qualified electrician who also happens to be my friend. I am making it easier for him by doing all the grunt work...

I am guessing there is no height restriction for the SWA?

Thanks
 
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450mm comes from my DNO background. 500mm it is then if thats the spec for private cable. I will be using the SWA as the cpc from the CU in the house.


Below is the route. Hence why I am erecting the cable along the wall.

cableroute.jpg
 
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And the consumer unit. That socket appears to be in the way unless there is another way in. The wooden paneling is fixed into place. It is a split board with spare ways on the left.

CU.jpg


CUWays.jpg
 
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Yeah thats why I am not bothering with a RCD in the shed. So there is the option of upstairs or downstairs split of the board. I guess downstairs is more critical so I'll connect it to the upstairs of the board. Unless of course the board has been split equally regards to load.
 
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What is wrong with exporting the earth from a PME system? The earth loop impedance will still be within the required value. Or are you thinking about circulating currents if both ends of the SWA is earthed?

Thanks.
 
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Sorry sorry .sorry sorry .sorry sorry .sorry sorry .sorry sorry .sorry sorry .sorry sorry .sorry sorry .sorry sorry .sorry sorry .sorry sorry .sorry sorry .sorry sorry .sorry sorry .sorry sorry .sorry sorry .
 
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Well I take it exporting PME is fine, as there are no extraneous-conductive-parts, and if the shed is all wooden (insulating), then a perfectly adequate equipotential zone can be constructed using just the cpc and so it doesn't seem any more hazardous then using PME inside a house[FONT=Arial, Helvetica, sans-serif]. [/FONT]
 
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Helm-Electric said:
Well I take it exporting PME is fine, as there are no extraneous-conductive-parts, and if the shed is all wooden (insulating), then a perfectly adequate equipotential zone can be constructed using just the cpc and so it doesn't seem any more hazardous then using PME inside a house[FONT=Arial, Helvetica, sans-serif]. [/FONT]
Click to expand...

Absolutely and where there are extraneous-conductive parts, the zone can still be extended but that cpc would have to be sized to meet the requirements of a main protective bonding conductor too.
 
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Thanks IQ. No metal frame in shed. Just out of curiousity, what do you with a CEW system? Just continue the earth through in the same scenario?
 
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The other half was asking if the cable could just be under the stone chuckies when going along the side of the house (she doesnt like the idea of cable along the wall - aesthetics and all that) before going to 500mm when it reaches the backgarden. My initial thought is no its not acceptable, but I might as well ask the question and I can feed that back to her!

Or I volunteer her to do all the digging if she really wants it underground all the way ;)
 
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Guitarist said:
How about running it inside 32mm white waste pipe along the side of the building? She may find that less intrusive than black swa. Just a thought
Click to expand...


I have got black polypipe already.. so will this suffice? I want to do it properly, no short cuts.

Below is how I think I may be able to connect the SWA without disrupting the wooden paneling that my current house CU is on. Basically, the tails get split from the meter via a new 2 way CU with RCD.

ConnectingSwa.jpg
 
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It is under 3m. 16mm suffice? Overall, no quams with the above idea? The shed end wouldnt have a RCD as it would rely on the RCD back on the new 2 way CU in the garage.
 
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To be honest with your design criteria and protection devices in the shed CU you could get away with 4mm but personally I would go 6/10mm
 
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Load wont exceed 2kW and volt drop is only 4.4V at 20A over 20m (4.6kW at 230V 1.91% VD).

The design is adequate for what I need to use it for. There will be nothing hefty supplied from it.
 
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An even tidier approach if you have that spare way is to connect the SWA direct into the CU, saves you messing with tailis and of course isolation of the installation to fit a new Cu ................

You can then if there is an unprotected way in the CU connect to that. and have your RCD local
 
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It is a split board protected by a RCD on each side. Have various options in my head and looking at the pros and cons and great to get feedback from you guys for each proposal. The separate RCD would be on the side fed from a spare way in the board. Would be far easier to hook up than fit the SWA direct to the board using a 3 x 3 metal box for the glanding. I've not opened the CU up yet to see whats going on in there. Will do it when the Doris is out (so she doesnt complain about power being off) and post a pic up.
 
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Running a new SWA to supply a shed
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