Paulbarrett
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zx9
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When we had the loft extension done it was signed off by the sparkie in an email to the local council who then issued the certificate again by email. I still found an un connected T&E to the shaver point in the bathroom, no wonder it did not work, Friday afternoon testing I guess! My point is just because you use a registered sparkie and the install has been tested don't assume it has been done correctly.
Screwdriver
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You can do whatever you want in your shed if it's on the end of a plug, it's just an extension. So use a dedicated outlet on your house consumer unit and wire it up to a 16amp socket. You may need a qualified electrician but the law states it has to be done by "a competent person". Then just run a SWA cable out to the shed and you can terminate that in your own consumer unit in the shed. So long as the entire shed is fed from a detachable plug and socket, it won't require any form of certification whatsoever.
Personally I wouldn't run a setup like that from an RCD, a type C MCB will be sufficient at the house end, then have an earth spike locally at the shed end for any local RCD devices. This type of arrangement usually provokes highly technical arguments around earth loops and whatnot but this is how my workshop is setup and its been absolutely fine for 15 years. Among all the large workshop machinery including lathes, grinders etc. I can happily run 200A welders 25m from the house and even from a further extension running out to the garage. I bit the bullet and went for an over spec 1.6mm SWA which I thoroughly recommend otherwise the voltage drop over a long distance can cause unending problems in the long term.
Screwd.
Personally I wouldn't run a setup like that from an RCD, a type C MCB will be sufficient at the house end, then have an earth spike locally at the shed end for any local RCD devices. This type of arrangement usually provokes highly technical arguments around earth loops and whatnot but this is how my workshop is setup and its been absolutely fine for 15 years. Among all the large workshop machinery including lathes, grinders etc. I can happily run 200A welders 25m from the house and even from a further extension running out to the garage. I bit the bullet and went for an over spec 1.6mm SWA which I thoroughly recommend otherwise the voltage drop over a long distance can cause unending problems in the long term.
Screwd.
Wendelspanswick
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I hope that's a typo and you mean 16mm SWA and not 1.6mm SWA?
Screwdriver
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I hope that's a typo and you mean 16mm SWA and not 1.6mm SWA?
Actually it's a typo and I mean 1.5mm²... (25 amp)
Wendelspanswick
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25 amps at 25m (buried underground or in ducting) needs 4mm!
http://www.doncastercables.com/technical-help/
1.5mm SWA is only safe upto 13amps at that distance and installation method.
dobbslc
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1.5mm?
Jeez that's small missus!
I've uprated mine from 2.5 mm to 4mm as it was too small for anything useful.
You have to watch the de-rating factors as running a cable in "Free air" gives it a higher rating than if it's "buried"
Jeez that's small missus!
I've uprated mine from 2.5 mm to 4mm as it was too small for anything useful.
You have to watch the de-rating factors as running a cable in "Free air" gives it a higher rating than if it's "buried"
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brightspark
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one lighting circuit and one ring main in mine with an armoured 35 mm supply cable to an old wylex 4 way db . been like that for the last 25 years 
brightspark
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there was worse than that as well
steviec_lj
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I'd personally ignore 99% of this.
There are strict calculations for exporting an earth, not all installations are suitable, and you can't just chuck an earth spike in for good measure.
There are also areas you can and can't do electrical work yourself.
Bathrooms, kitchens and outside are definitely all covered by part p.
Replacing an existing circuit like for like isn't, last time I read up on it.
Mine is 16mm2 2core SWA clipped direct for 14mtrs and then buried for 20mtrs, well over spec for what I want, but lighting circuits are sensitive and there are calculations for allowable voltage drop over distances.
How not to do it..
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I like the idea of emergency stop switches, where can I get a couple?Personally for the cost...6mm2 SWA or ideally 10mm2 2 core or 3 core SWA
6mm2 on a 40Amp Type C MCB in the house
10mm2 on a 50Amp Type C MCB
Ideally all RCBO garage board (you DON'T want a single RCD...especially with a Mill / Lathe...RCD goes click...your then in the dark with objects still rapidly spinning near you.
Personally
1 x 6amp RCBO for the lights
1 x 20Amp Type C RCBO to run a pair of 16Amp commando sockets
1 or 2 x 20Amp Type C RCBO
20mm black high impact conduit and metal clad sockets/light switches. (stops the cables getting damaged)
(Though I've still got to stick the board and cabling into mine - which is severely over the top)
Mine (OTT)
2 x 6Amp (lights split into 2 banks)
1 x 10 Amp (outside lights
All below apart from the 6Amp MCB and the fan RCBO are wired through a pair of contactors to cut the power if any of the 3 e stops are hit ( lights stay on and fans stay on though)
1 x 16Amp (13amp sockets for chargers/radio)
2 x 20Amp (one socket radial each side with 3 doubles on each side)
2 x 32 Amp (2 x 32 commando sockets)
2 x 16Amp (2 x 16 amp commando sockets)
1 x 16Amp (fused down to 3Amp - 2 x 6" extractor fans)
1 x 6amp MCB - power to Emergency stop switches
Though I've still got all my testing kit from my sparking days and I'm in Scotland so no Prat P to deal with
All that for a 6x3 garage/workshop
told you it was OTT.......
What is the purpose of 32 amp sockets? I.e, what do you plug in to them? I've only said I want some 16 amp ones as I could put my welder and on a compressor when I get one.
What is the difference/how do you choose between MCB RCD, RCBO? I know what they all stand for, just not what they do.
Maker
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Don't know what I'm looking at here, what's wrong with it?
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Screwdriver
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Works for me. I know the arguments regarding earthing and I am entirely satisfied with the solution I have employed.
What are the regulations regarding having a shed running from an extension socket?
S.
steviec_lj
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MCB is like your old cartridge fuse, it will trip when you pull more amps than its rated for, plus its resettable.
RCD detects phase/neutral imbalance, and trips. These usually cover numerous circuits.
RCBO is a combination of both of the above.
Choosing them is where you need calculations, power factors and demand and diversity.
RCD detects phase/neutral imbalance, and trips. These usually cover numerous circuits.
RCBO is a combination of both of the above.
Choosing them is where you need calculations, power factors and demand and diversity.
steviec_lj
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A shed can run from an extension cable. SWA is an installation, not an extension cable.
You could use SY cable, but this isn't rated for outdoor use.
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steviec_lj
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Now that's getting technical, I was keeping it simple for the poor chap..
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Depends on installation method
