Why do you have appliances at 240v rather than have all be 120v?

Answer 1

Answer for USA, Canada and countries running a 60 Hz supply service.

When a load is applied from either 120 volt conductor to the neutral (as is the case for typical receptacles, lights, and so forth) it is using 120 volts.

However, when a load is applied from one 120 volt conductor to the other, without using the neutral, the voltage being used is the sum of both 120 volt conductors (240 volts). This is the case for many water heaters, air conditioners, electric furnaces, clothes dryers, and so forth.

For more information see the answers to the Related Questions shown below.

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As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.

Before you do any work yourself,
on electrical circuits, equipment or appliances,
always use a test meter to ensure the circuit is, in fact, de-energized.

IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.

Answer 2

In Europe and many other countries 240 V is the normal supply, so all appliances are designed for that voltage. 240 V is more dangerous than 120 V, but it does make appliances more compact because the current flow is halved, also the house wiring can use smaller conductors

Answer 3

Power output of an appliance is the square of the voltage divided by resistance (P=E squared/R).

Appliances which must produce large amounts of heat (e.g. stoves, dryers, baseboard heaters) are operated at 240 volts so that doubling the voltage will quadruple the heat produced. Since most homes are wired with a 3 wire 120/240 volt system, bringing 240 volts to heating appliances can be accomplished by installing 2 pole breakers on a standard 2 wire circuit.

Answer 4

The loss of electrical energy in the wires that carry it to the appliance is proportional

to the square of the current (Amps) in the wire. So, for example, a device that uses

ten times as much power to do its job causes (10)2 = 100 times as much to be lost

in the wires.

A clock radio uses perhaps 5 watts of power, a light bulb maybe 40 to 100 watts.

An electric oven uses something like 3,000 watts when it's on, and a clothes dryer

something like 4,500 watts.

If the major appliances ran from the same supply as the small ones, then compared to

a 100-watt incandescent light bulb, the electric oven would lose 900 times as much

as the light bulb loses, before the power ever reaches the appliance to start doing its

job, and the dryer would lose 2,000 times as much. Besides the unnecessary expense,

the lost energy also heats the wires !

By supplying the power at higher voltage, the required current (Amps) decreases by half,

and the loss in the wires decreases by 75% .

Answer 5

It all has to do with Ohm's law. Basically, the higher the voltage is, the cheaper it will be to run. That is the most over simplified way to answer your question.

Answer 6

Less current is needed

Answer 7

voltage ratings are pluss or minus 10%