07-03-2015, 07:26 PM
I must admit that the more I search around the subject, the more confusing it becomes. As I said, I'd done quite a bit a few years back, and I did a fair bit before my earlier reply. The lack of consensus was the overriding conclusion, which is why I'd be tempted to "outsource" the decision to someone willing and able to sign off the work. But I agree that can be easier said that done 
With a 13A fuse in the BS1363 plugtop, feeding 16A cable, and also being RCD-protected just inside the house, I think that you've covered most bases. SWA cable obviously offers much-improved mechanical protection, but is a PITA to terminate. And gets away from the "extension cable" philosophy.
While it probably doesn't meet the regs, I can't think of an obvious problem with it. Should you slice through the cable with a spade or loppers, the fuse and RCD should offer decent protection. Should the roof get ripped from your shed during a freak storm, any water ingress will trip your RCD plugtop in the house. If you include at least one emergency light fitting, then that makes things much safer after dark.
I've had to study "temporary installations" used by OB vehicles in the past, and these often run from 13A BS1363 outlets at a venue. So, not much different to what you are doing. The complication arises with the earth connection, and the fact that like you, many venues don't know about their incoming earth. Measuring the earth-loop impedance normally gives a decent indication of the earth type. It might be worth measuring the earth-loop impedance at the outlets in your shed, but even if it's a bit high, the plugtop RCD should take care of that.
Interestingly, the mains cables on some of these vehicles are 13A BS1363 to 16A "C-form". Once inside the vehicle, there is a full and comprehensive installation. I can't help wondering if you could do a similar thing - mount one of those on a wall of the shed, so the cable can be disconnected at either end. Inside the shed, I don't see why you shouldn't install as many sockets and lights as you want. If you wanted to be smart, how about including a cheap voltage meter: http://golbornevintageradio.co.uk/forum/...p?tid=3299
With a 13A fuse in the BS1363 plugtop, feeding 16A cable, and also being RCD-protected just inside the house, I think that you've covered most bases. SWA cable obviously offers much-improved mechanical protection, but is a PITA to terminate. And gets away from the "extension cable" philosophy.
While it probably doesn't meet the regs, I can't think of an obvious problem with it. Should you slice through the cable with a spade or loppers, the fuse and RCD should offer decent protection. Should the roof get ripped from your shed during a freak storm, any water ingress will trip your RCD plugtop in the house. If you include at least one emergency light fitting, then that makes things much safer after dark.
I've had to study "temporary installations" used by OB vehicles in the past, and these often run from 13A BS1363 outlets at a venue. So, not much different to what you are doing. The complication arises with the earth connection, and the fact that like you, many venues don't know about their incoming earth. Measuring the earth-loop impedance normally gives a decent indication of the earth type. It might be worth measuring the earth-loop impedance at the outlets in your shed, but even if it's a bit high, the plugtop RCD should take care of that.
Interestingly, the mains cables on some of these vehicles are 13A BS1363 to 16A "C-form". Once inside the vehicle, there is a full and comprehensive installation. I can't help wondering if you could do a similar thing - mount one of those on a wall of the shed, so the cable can be disconnected at either end. Inside the shed, I don't see why you shouldn't install as many sockets and lights as you want. If you wanted to be smart, how about including a cheap voltage meter: http://golbornevintageradio.co.uk/forum/...p?tid=3299
