Electricity around the world

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There is no standard mains voltage throughout the world and also the frequency, i.e. the number of times the current changes direction per second, is not everywhere the same. Moreover, plug shapes, plug holes, plug sizes and sockets are also different in many countries. Those seemingly unimportant differences, however, have some unpleasant consequences.
Most appliances bought overseas simply cannot be connected to the wall outlets at home. There are only two ways to solve this problem: you just cut off the original plug and replace it with the one that is standard in your country, or you buy an unhandy and ugly adapter.

While it is easy to buy a plug adapter or a new “local” plug for your “foreign” appliances, in many cases this only solves half the problem, because it doesn’t help with the possible voltage disparity. A 120-volt electrical appliance designed for use in North America or Japan will provide a nice fireworks display – complete with sparks and smoke – if plugged into a European socket.

It goes without saying that the lack of a single voltage, frequency and globally standardised plugs entail many extra costs for manufacturers and increase the burden on the environment.

Pure waste and unnecessary pollution !

Single-phase voltage and frequency

Look-up table (single-phase voltage, frequency and plug/sockets)

Plugs and sockets

What do I need to use my appliances abroad ?

Why can only “electric” appliances be used with a converter, and not “electronic” ones ?

Trick to know the local voltage and frequency

Three-phase voltage, frequency and number of wires

Single-phase voltage and frequency

Europe and most other countries in the world use a voltage which is twice that of the US. It is between 220 and 240 volts, whereas in Japan and in most of the Americas the voltage is between 100 and 127 volts.

The system of three-phase alternating current electrical generation and distribution was invented by a nineteenth century creative genius named Nicola Tesla. He made many careful calculations and measurements and found out that 60 Hz (Hertz, cycles per second) was the best frequency for alternating current (AC) power generating. He preferred 240 volts, which put him at odds with Thomas Edison, whose direct current (DC) systems were 110 volts. Perhaps Edison had a useful point in the safety factor of the lower voltage, but DC couldn’t provide the power to a distance that AC could.

When the German company AEG built the first European generating facility, its engineers decided to fix the frequency at 50 Hz, because the number 60 didn’t fit the metric standard unit sequence (1,2,5). At that time, AEG had a virtual monopoly and their standard spread to the rest of the continent. In Britain, differing frequencies proliferated, and only after World War II the 50-cycle standard was established. A mistake, however.

Not only is 50 Hz 20% less effective in generation, it is 10-15% less efficient in transmission, it requires up to 30% larger windings and magnetic core materials in transformer construction. Electric motors are much less efficient at the lower frequency, and must also be made more robust to handle the electrical losses and the extra heat generated. Today, only a handful of countries (Antigua, Guyana, Peru, the Philippines, South Korea and the Leeward Islands) follow Tesla’s advice and use the 60 Hz frequency together with a voltage of 220-240 V.

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 the US is still evolving from the 50s and 60s, and – mostly in older buildings – 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.

Look-up table (single-phase voltage, frequency and plug/sockets)

There are 214 countries listed below. 175 of the countries mentioned use 220-240 volts (50 or 60 Hz). The 39 other countries use 100-127 volts.

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

* In Brazil there is no standard voltage. Most states use 127 V electricity (Acre, Amapá, Amazonas, Espírito Santo, Mato Grosso do Sul, Maranhão, Pará, Paraná, Rondônia, Roraima, Sergipe and Minas Gerais). Other – mainly northeastern – states are on 220 V (Alagoas, Brasília, Ceará, Mato Grosso, Goiás, Paraíba, Rio Grande do Norte, Santa Catarina and Tocantins). Although in most parts of the states of Bahia, São Paulo, Rio de Janeiro and Rio Grande do Sul 127 V is used, the cities of Santos, Jequié, Jundiaí, São Bernardo do Campo, Novo Friburgo, Bagé, Caxias do Sul and Pelotas run on 220 V. The states of Pernambuco and Piauí use 220 V, except for the cities of Paulista and Teresina (127 V).

** Although the mains voltage in Japan is the same everywhere, the frequency differs from region to region. Eastern Japan uses predominantly 50 Hz (Tokyo, Kawasaki, Sapporo, Yokohama, Sendai), whereas Western Japan prefers 60 Hz (Osaka, Kyoto, Nagoya, Hiroshima).

*** Saudi Arabia uses 110 V in many parts of the country, such as the Dammam and al-Khobar area (situated in the eastern province of Ash Sharqiyah). 220 V can be commonly found as well, especially in hotels.

**** In Tahiti the frequency is 60 Hz, except for the Marquesas archipelago where it is 50 Hz.

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