A barn is unlikely to be directly supplied, but 'exported' from the adjacent farm house. And will then be protected by the supplier's RCD. And if it really did have a knife switch that dates back to DC days - ie before WW2. I've never seen one outside a museum of such things. ;-)
But as circuit breakers in domestic installations?
No one in their right mind uses electricity for heating. We use gas or oil. It would only make sense if that electricity was generated by some other fuel - like renewable energy. But not if it's generated by oil or gas.
You can get very close to 100% efficiency with a condensing gas boiler - not really possible with a variable demand gas burning power station, even before the transmission losses.
--
*Life is hard; then you nap
Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.
Crikey !! I didn't know what I was starting when I opened this thread !
OK. Lets put some figures on it.
Last figures I could find were for 2003. Total UK generation capacity was
78.5GW at that time. Power generation for the year was 376.8 BkWH. Power consumption for the year was 399.8 BkWH, a shortfall of some 5.1 BkWH, which was imported from our grid connection to mainland Europe, via France.
There are some 23 countries cross connected in the European grid, supplying approx 450m people ( that's a few more than the U.S. grid ... )
The typical cross border capacity appears to be 2 way - ie to two adjacent network operators -at 2.5 GW per way - a net import / export capability of 5 GW per border crossing.
The original UK / France undersea cableway, comprised two single conductor cables with a DC capacity of 160MW total ( the power is rectified to DC and reinverted to AC at either end ). This cable has since been replaced with a
4 cable system, each comprising a positive / negative pair. These are buried in the sea floor in trenches 600mm wide, separated by 1 km to avoid interaction of the magnetic fields with marine navigation equipment.
The total capacity of this connection is 2GW DC net import / export.
The total consumption of the 23 countries, is around 2300 TW.
So, a total grid somewhat larger than the US one,in terms of subscribers, and quite possibly in distances and geographical area, and to the best of my knowledge, it has never fallen over in such a spectacular way as the US one sometimes does.
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.