I'm quite happy with my wish. I've seen led clusters in a MR16 package deliver the equivalent light to a 43W incandescent for a consumption of 3.6W: that's 300mA at 12V. Our rooms over here are probably smaller than yours, Jim, but I might have 4 ceiling-mounted units to give me a nice light in most of my rooms (<150sq ft). Our lighting wiring is mostly rated 5A, so, the 1.2A ac/dc I would need is well within spec if I just put a 12V transformer on the lighting circuit. So, in my house (fairly typical in the UK) my wiring would not change, but in a new build it could be not only smaller, but not have an earth/ground wire with it and no outer sheath, ie just twin. That's a lot less copper and a lot less pvc. It's easy to incorporate thermal trips (ptc devices) which are cheap and last my lifetime.
All this adds up to taking a lot less current out of the mains and therefore a lot easier to suppress if switching supplies are used. Sorry for the thread drift, but it's an interesting subject. David G3UNA > On 4/3/2011 3:24 AM, David Cutter wrote: >> I'm looking forward to a time when all domestic lighting can be run >> from a 12V supply at the main switchboard. > > Be careful what you wish for. A major advantage of higher voltage > distribution is that copper losses are much less, and much smaller > copper conductors are required. This makes the 240V system used in much > of the world superior to the 100V and 120V systems used in Japan and > North America. It gives 240V a 20:1 advantage over 12V. > > More important, try a quick calculation for the cost of converting every > building in the world from the existing 120VAC or 240VAC to your 12VDC. > Remember -- none of the old wiring is sufficient, so one must rip out > the walls and start over. Please tell me when this is going to happen -- > I want to buy stock in the copper industry, because the price is going > to multiply by a factor of at least 5X, because copper is going to > become VERY scarce. > > In addition, distribution of power as an AC voltage means that it is > easily transformed from one voltage to another by transformers that > don't make electrical noise. The electrical noise produced by switching > power supplies to do that would wipe out all radio communications! > > 73, Jim K9YC > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
