[Elecraft] Curiosity Only, somewhat off topic.

[Ron D'Eau Claire]

Most American homes have 240V at the entrance (circuit breaker or
distribution) panel. But, since most US electrical appliances and lamps have
been 120V for(almost)ever, the electrical system is split with 120V single
phase running to most outlets. 240V service is supplied to things like
electric furnaces, electric clothes dryers, electric kitchen ranges, etc.
Unless directed otherwise, most builders do not provide 240V outlets
elsewhere in the home. Other than Hams, perhaps the most common place for
240V service these days is in a workshop with power tools.  

When a 240 outlet is added, it is on a dedicated circuit from the 240VAC at
the main panel, not via transformer from 120V. And the reason is just as you
note: it takes a lot of copper to maintain a decent voltage under heavy
load. A KPA500 running full power, for example, will heavily load most 120V
circuits. Upgrading to a 240V service for the Ham shack avoids "popping" a
circuit breaker should something else be connected to the same circuit and
helps with overall voltage regulation. 

I don't know that there's a significant safety difference between 120 and
240 VAC. Indeed, there may be a safety improvement by lowering the current
demand, hence less heating in the outlet boxes, at 240V. 

Ron AC7AC

-----Original Message-----

I noted recently several refs by USA users asking about 240 volt ac power
plugs etc.

Now I have never even been to a 110v  country -  possibly only USA ? -
and
I can see a degree of (shock)  safety offered with that system, but I can
hardly imagine the mass of copper required to carry possibly 200 amps
around the house.   Nevertheless, I just wondered why there seems such
interest in running 240v equipment, presumably via suitable transformer.
                     David VK3DBD/G3SCD.
.
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