Sorry 'bout that electrifying mistake.
Here is the post again:
Back in the old daz there was only 110 (or was it 120?) and 220 for all practical
purposes (in the home). Now there is this new-to-me 240. What is this 240
and what happened to 220 (for that matter what happened to 110)? I am purchasing
some electric baseboard heaters that are "220", so what happens now. Do i
have the house wired for 220 for the heaters or will 240 do it?
Here are the heaters. Awful, slow website HYDRO-SIL:
Posted Via Uncensored-News.Com - Accounts Starting At $6.95 -
Umm, "220" went bye-bye about 50 or more years ago when the nominal
voltage supplied to homes was raised from 110/220V to 120/240V, possibly
in steps (I've seen 115V and 117V listed as the standard voltage).
For some odd reason, nearly everyone, including professional electricians
refers to the 240V two hot supply as "220". 240V is what you should see
on the spec. plate of every non-ancient "220" device you see. (you
might see 208V/240V rarely, also OK, though 208V only devices may be
overstressed on 240V or won't work at all because they require 3 phase)
The original 110 V was Thomas Edison's best voltage for safety and the
operational characteristics (resistance) of the carbon filament lamps
at the time. The voltage also had to be high enough to overcome the
effect of voltage drop from the DC central stations extensively used
back then and since there were no transformers, the lamps could be
operated only within a mile or two of the central station without
excessive dimming. Initially, Edision only believed in DC until
Westinghouse made him see the light (literally). Only the AC systems
allowed transmission and conversion over extremely long distances.
As modern AC systems evolved, the higher voltage (120 V) was specified
as a standard as it allowed more efficiency (less voltage drop) and
allowed more power to be transferrred without too much of a compromise
During the 1930's, the US 110/220 V system was developed and promoted
by the U.S. Rural Electrification Agency (a unit of the Department of
Agriculture) as the best way to electrify rural America and became the
North American Standard.
European systems at the dawn of the 20th century were dominated the
standards set in Germany where the great manufactuers (Seimens, etc.)
set the pace and it was decided that 220 V. at 50 Hz would be the way
to go. The higher voltage meant that systems could be built with
less copper (copper was a critical wartime commodity and for the most
part, Germany was either fighting or preparing for the next war),
smaller transformers (less iron required at 50 Hz than 60 Hz), and,
greater efficiency with a corresponding greater shock hazard. A
shock from a 220 V. circuit hurts a lot more than one from a 110 V.
circuit, although it is easy for either one to kill you.
I thought it was the reverse of that. Higher frequency gives a lower V.s
integral therefore less flux and less iron required. I think 400Hz systems
are used in some applications to get size and weight down.
You're correct. Many US appliances are designed to work at 50/60 Hz,
including most military equipment. This requires a slightly larger
transformer, (iron), core, but with proper windings it makes appliances
that can be used in Britain and Europe. I was in Italy during WWII, and
the frequency sometimes went as low as 42 Hz! We would have to switch
to diesel generators.
400Hz has long been used in aircraft, because of the much lower
transformer weight. Much WWII military surplus was from equipment
designed for 400Hz.
The standard ATX computer power supply doesn't use a line transformer,
so it will work at any frequency.
That's certainly not the reason in the UK. The initial local generating
stations in cities were normally 100V (or slightly higher to allow
100V to be obtained at the ends of the local cable runs). Most
city centres passed bylaws forbidding overhead cables, so the cables
were buried under the streets. As the power required rapidly increased,
it wasn't easy to string thicker cables as was done in the US, so
instead the voltage was doubled.
First sorry for my english, I'm french...
The voltage was encrease from 110V to 120V to have better performance
i.e. have a lower current for the same power. If the current decrease,
the wires drop voltage is lower and the load have more power available.
Now, your hold wires are able to support 120V or 240V because the minimum
isolation wire is 300V. Also like I wrote before, the fact that the voltage
=> a decreasement of current. The wire size (dimeter) is establish with the
passing trough the wire. If the current wire decrease, your hold wire could
secure than a new one calculate with the present current...
One important thing is: do not have aluminum wires because they could
(slack) with time and brings many problems.