If National Grid install a new main fuse and meter in my new porch then how can i connect it to the existing consumer units 10 meters away?
Maybe a 100ma 100ms RCD by the new main fuse and then a fat cable burried in a wall?
This is because of th extension I'm building,
George
You will need a switch fuse immediately after the meter and 25mm2 meter tails and a 16mm2 earth.
You will also need some form of mechanical protection on the route if it is buried in anything like plaster like 3mm thick stainless steel sheet suitably deburred and possibly earthed too.
(been there, done that and got the T shirt when the new consumer unit was fitted to a new location and the old CU removed)
I think up to 5m of tails to the switch-fuse is allowed?
the switchfuse is a protective device for protecting the tails so thats why it has to be at the beginning of the meter tail run.
There is a limit on how long the meter tails can be before a switch fuse is required, which if my memory serves me right is 3m but I am sure ARW will be along soon to correct me!
S.
You're right 3m not 5m.
But I mentioned it in case for some reason george doesn't want the switchfuse immediately next to the cutout (e.g. the outer porch door might not be lockable, so you don't want johnny burglar waltzing in and turning off the power).
Well, I guess all you can say is on their side it will protect their systems, on yours its up to you what you do as long as its not making it supply a canherbis farm, presumably, before the meter. Brian
I'd be inclined to use SWA.
does SWA exist that has 25mm2 cores? it would also be harder to work with in terms of burying in the walls & plaster.... and to bend and feed through holes drilled in joist centres.
Yes:
Yes:
For internal use, I might be thinking about singles in steel conduit as the bends could be easier to manage than SWA's radii.
Theo
More likely split concentric?
Maybe, although I thought standard install was three phase these days?
Theo
Presumably this picture isn't showing the correct product?
It seems like they have a 3 core version but is that 3 concentric cores, or three cores in a single sheath like this:
Before I bought this house, the meter was moved from the cellar to the top of the cellar stairs - where the CU is also located. And the supply from cutout to meter is 3 core SWA - with the third core being used for the earth. I assume this was done by the electricity supplier of the day. But elsewhere in London, I've seen MI used for the same thing.
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