20 Mar
2011
20 Mar
'11
12:15 p.m.
On 2011 Mar 20, at 12:43 AM, Eric Smith wrote:
That seems far more sensible than the 120/240V "split-phase" wiring
used in residential and light business here in the US. I assume that
we use split-phase because putting a single-phase transformer on the
power pole is less expensive than a three-phase transformer. It's
also stupid that we use such a low voltage; it means that only a few
outlets in a US house are wired for 240V, generally just the
stove/range, clothes dryer, central water heater, and furnace. (Where
available, people use natural gas for those instead, as it costs
less.) Electric kettles, room heaters, etc. have to run on 120V at
15A or less, so they are very slow.
I suspect our 120/240V (also 110V,115V,117V) split-phase distribution
is a legacy of the "War of the Currents" between Tesla/Westinghouse and
Edison. When Westinghouse entered they presumably had some interest in
compatibility for end-users and existing loads with Edison's early
distribution system, which was 3-wire and conceptually similar: +110,
-110V & neutral.