This article has 1 Comment

  1. Originally Europe was 120 V too, just like Japan and the US today. It has been deemed necessary to increase voltage to get more power with less losses and voltage drop from the same copper wire diameter. At the time the US also wanted to change but because of the cost involved to replace all electric appliances, they decided not to. At the time (50s-60s) the average US household already had a fridge, a washing-machine, etc., but not in Europe.

    The end result is that now, the US seems not to have evolved from the 50s and 60s, and still copes with problems as light bulbs that burn out rather quickly when they are close to the transformer (too high a voltage), or just the other way round: not enough voltage at the end of the line (105 to 127 volt spread !).

    Note that currently all new American buildings get in fact 240 volts split in two 120 between neutral and hot wire. Major appliances, such as virtually all drying machines and ovens, are now connected to 240 volts. Mind, Americans who have European equipment shouldn’t connect it to these outlets. Although it may work on some appliances, it will definitely not be the case for all of your equipment. The reason for this is that in the US 240 V is two-phase, whereas in Europe it is single phase.

    Roughly speaking, to operate a particular appliance requires a particular amount of POWER, which (at least for resistive loads) is current times voltage. If you double the voltage, you draw half the current to achieve the same power. The primary advantage of lower current is that you lose less power in the wires feeding current to the appliance (or you can use smaller, cheaper wires for the same power loss rating). On the other hand, the higher voltage is somewhat more dangerous if accidentally touched or if there is an accidental short circuit. Some experienced electricians are relatively casual about touching 110 V circuits, but all respect 230 V. (This constitutes a “don’t-try-this-at-home thing, though–it’s quite possible to get a fatal shock or start a fire with 110 V!) Current trends are toward the use of even lower voltages (24 V, 12 V, 5 V, 3.3 V…) for any devices which don’t draw much total power to increase safety. Power is rarely distributed at these lower voltages; rather it is converted from 110 V or 230 V by a transformer at the earliest opportunity. Even in North America, 220-240 V is commonly used in residential appliances for
    most high-power electrical appliances (ovens, furnaces, dryers, large motors, etc.) so that the supply current and supply wire size can be smaller. Higher power industrial applications often use 480 V or more. And, of course, transmission lines use progressively higher voltages as the distance and total power go up (22,000 V for local distribution to 1,000,000 V for long distance lines).

    from
    http://thednetworks.com/2012/06/10/why-does-ukusa-use-110120v-and-others-use-220240v/

Leave a Reply