# electric power

Electric power has three main characteristics:

## Voltage

Voltage is often compared to pressure in a water pipe. The higher the voltage, the thinner the wire needed to carry a given amount of current. Long distance transmission lines operate at thousands of volts, because that makes it possible to use thinner wires.

The choice of a voltage for homes is a compromise between safety and economy. For example, in the United States house current is 110 volts; in Europe it is often 240 volts. Lower voltages (for example, 120 volts instead of 240 volts) are safer but require thicker wires.

Generally, running an appliance on the wrong voltage will ruin it.

## Alternating current or direct current?

Electricity from a battery is direct current: the electrons move in one direction. The first power plants also produced direct current.

It is possible to reverse the direction of the current in a constantly repeating pattern. Electric current in which the direction is constantly changing is called alternating current, or AC. The wire that is positive becomes negative and the negative wire becomes positive. Electricity sold in the United States goes through a compete cycle 60 times each second; it is 60-hertz (60-Hz) alternating current. For ¹⁄₁₂₀ of a second the current flows one way, and for the next ¹⁄₁₂₀ of a second it flows the other way.

Transformer used by consumers to run an appliance made for one country in another. It converts 110 volts to 220, or vice versa.

Courtesy Powerbright.

Alternating current has almost completely replaced direct current, mainly because the voltage of an alternating current can be easily raised or lowered using a transformer. A transformer depends on having wires in a constantly changing magnetic field, and the changing magnetic field is produced by changing the voltage.

With alternating current there are two instants in every cycle when the voltage is zero; those are the instants when the current is changing direction. From these instants, the voltage slowly increases to a peak and then slowly decreases. The ideal pattern is a sine wave. (For simplicity's sake, we are leaving amperage out of this discussion. The amperes may lead or lag the voltage, depending on the load.)

We have spoken of electrons moving down the wire, but electrical energy is transmitted by the push the electrons give their neighbors, not by their “flow”. Imagine a line of people waiting for a bus. The person at the end of the line gives the person in front of him a shove. That person gives the person in front of him a shove, and so on, until the shove reaches the man at the other end of the line. He shoves back, and the shove passes back the line to the original shover. Energy has been transmitted, but everyone is still in the same place. That is alternating current. Even in direct current, the energy travels through wires much faster than the electrons themselves do, just as a wave travels over the surface of the ocean more rapidly than the water itself moves.

## Phase

The voltage falling to zero is perceptible in the flickering of old-fashioned fluorescent lights, and even in the performance of electric motors. To get a more nearly constant source of power without giving up the advantage of alternating current, engineers turned to three-phase power. Three-phase power requires a minimum of 3 wires; single-phase power can be delivered with two. Having three wires makes three possible pairs (AB, AC, BC). When the voltage across one pair of wires is zero, the voltage across the other two pairs is not. So a three-phase motor will run more smoothly than a single-phase motor.

## Grounding

In some countries the earth itself is used as one of the conductors in the electrical system. The way in which the ground is used differs greatly from country to country.

## World Standards

Almost all the electricity now sold in the United States is 60-Hz alternating current. In homes, the voltage is approximately 120 volts, but it may be brought into the house at a higher voltage, and high voltages are used for some power-hungry appliances, such as kitchen ranges, air conditioners and water heaters. (The higher voltage makes it possible to supply the same amount of power with smaller wires.) Three-phase power is rarely found in residences.

The appearance of the receptacle usually indicates what voltage and amperage is available, since the National Electrical Manufacturers Assn. (NEMA) and the NEC specify what type of current each receptacle design is to be used for.

The letters for the plugs and sockets, are arbitrary.

The American manufacturer of plugs and sockets is providing

http://www.interpower.com/cgi-bin/ic.cgi/guidelist.p

Nation Freq.
(Hz)
Phases Nominal
voltage
No. of wires Plugs & Sockets
Afghanistan 50 1, 3 220/380 2, 4 D
—Charikar 60 1, 3 220/380 2, 3, 4 D
Amer. Samoa 60 1, 3 120/240 2, 3 A, B, F, I
Angola 50 1, 3 220/380 2, 4 C
Antiqua 60 1, 3 230/400 2, 3, 4 A, B
Argentina 50 1, 3 220/380 2, 4 C, I
—Buenos Aires and a number of other cities also provide: direct NA 220/440 2, 3
Aruba 60 1, 3 127/220 2, 3, 4 A, B, F
Lago Colony 60 1 115/230 2, 3
Australia 50 1, 3 230/415 2, 3, 4 I
—Albany, Kalgoorlie, Perth 50 3 220/380 4
Austria 50 1, 3 220/380 3, 5 F
Azores 50 1, 3 220/380 2, 3, 4 B, C, F
—Punta Delgada, (this service is being phased out) 50 1, 3 110/190 2, 3, 4
Bahamas 60 1, 3 120/240 2, 3, 4 A, B
60 1, 3 120/208 2, 3, 4
Bahrain 50 1, 3 230/400 2, 3, 4 G
—Awali 60 1 110/115
60 1,3 220/240 3
Balearic Islands 50 1, 3 127/220 2, 3, 4 C, E
50 1, 3 220/380 2, 3, 4
Bangladesh 50 1, 3 220/440 3, 4 A, C, D, G, K
Barbados 50 1, 3 115/200 2, 3, 4 A, B, F, H
50 1, 3 115/230 2, 3, 4
Belgium 50 1, 3 220/380 2, 3, 4 C, E
—Anderlecht, Huy 50 1, 3 220/380 2, 3
—Charleroi, Mons 50 1, 3 230/400 2, 3
Belize 60 1, 3 110/220 2, 3, 4 B, G, E
60 1, 3 220/440 2, 3, 4
Bermuda 60 1, 3 120/240 2, 3 D, E
60 1, 3 120/208 2, 3, 4
Bolivia 50 1, 3 220/380 3, 4 A, C
—La Paz, Oruro, Viacha 50 1, 3 115/230 2, 3
—Cobija, Guayaramerin, Riberalta, Trinidad 50 1, 3 230/400 2, 3
Botswana 50 1, 3 230/400 2, 4 D, G
Brazil 60 1, 3 127/220 2, 3, 4 A through J
<_><_>big list here!!!!!
Brunei 50 1, 3 240/415 2, 4 G
Bulgaria 50 1, 3 220/380 2, 4 C, F
Burma 50 1, 3 230/400 2, 4 C, D, F
Cambodia 50 1, 3 120/208 2, 4
—Phnom-Penh 50 1, 3 220/380 2, 3, 4
—Sihanoukville 50 1, 3 220/380 2, 4
Canada 60 1, 3 120/240 3, 4 B
Canary Islands 50 1, 3 127/220 2, 3, 4 C, E
50 1, 3 220/380 2, 3, 4
Cape Verde 50 1, 3 220/380 2, 3, 4 C, F
Cayman Islands 60 1, 3 120/240 2, 3 A, B
Channel Islands 50 1, 3 240/415 2, 4 C, G
—Guernsey 50 1, 3 230/400 2, 4
Chile 50 1, 3 220/380 2, 3, 4 C, L
China 50 1, 3 220/380 3, 4 I
Colombia 60 1, 3 110/220 2, 3, 4 A, B
—Duitama, Honda 60 1, 3 120/208 2, 3, 4
—Sogomosa 60 1, 3 120/240 2, 3, 4
—Bogota (some older parts) 60 1, 3 150/260 2, 3, 4
Comoros 50 1, 3 220/380 2, 4 C, E
Costa Rica 60 1, 3 120/240 2, 3, 4 A, B
Cote d'Ivoire 50 1, 3 220/380 3, 4 C, E
Cyprus 50 1, 3 240/415 2, 4 C, G
Czechoslovakia 50 1, 3 220/380 2, 3, 4 E
Denmark 50 1, 3 220/380 2, 3, 4 C, K
Djibouti, Rep. of 50 1, 3 220/380 2, 4 C, E
Dominica 50 1, 3 230/400 2, 4 D, G
Dominican Rep. 60 1 110/220 2, 3 A
Ecuador 60 1, 3 127/220 2, 3, 4 A, B, C, D
—Quito and most cities also provide 60 1, 3 120/208 2, 3, 4
—Esmeraldas, Guaranda, and Guayquil provide 64. In addition to 66 and 67,
—Latacunga 60 1, 3 120/208 2, 3, 4
—Riobamba 60 1, 3 110/220 2, 3, 4
60 1, 3 127/220 2, 3, 4
Egypt 50 1, 3 220/380 2, 3, 4 C
El Salvador 60 1 115/230 2, 3 A to G, I, J, L
England 50 3 240/415 4 C, G
50 1 240/480 2, 3
Ethiopia 50 1, 3 220/380 2, 4 C, D, J, L
Faeroe Islands 50 1, 3 220/380 2, 3, 4 C, K
Fiji 50 1, 3 240/415 2, 3, 4 I
Finland 50 1, 3 220/380 2, 4, 5 C, F
France 50 1, 3 220/380 2, 4 C, E, F
being changed nationwide to 50 1, 3 230/400 2, 4
—Briancon 50 1, 3 115/200 2, 4
—Caen 50 1, 3 127/220 2, 4
50 1, 3 220/380 2, 4
—Grenoble 50 1, 3 127/220 2, 4.
—Lille 50 1, 3 110/220 2, 4
50 1, 3 220/380 2, 4
—Lyon 50 1, 3 110/220 2, 4
50 1, 3 127/220 2, 4
50 1, 3 220/380 2, 4
French Guiana 50 1, 3 220/380 2, 3, 4 C, D, E
Germany 50 1, 3 220/380 2, 4 F
Ghana 50 1, 3 230/400 2, 3, 4 D, G
—Sekondi, Takoradi, Tamale 50 1, 3 230/400 2, 4
Gibraltar 50 1, 3 240/415 2, 4 C, G
Greece 50 1, 3 220/380 2, 4 C, D, E, F
Greenland 50 1, 3 220/380 2, 3, 4 C, K
Grenada 50 1, 3 230/400 2, 4 G
Guadaloupe 50 1, 3 220/380 2, 3, 4 C, D, E
Guam 55       A, B
60 1, 3 120/208 3, 4
Guatemala 60 1, 3 120/240 2, 3, 4 A, B, G, H, I
Guinea 50 1, 3 220/380 2, 3, 4 C, F, K
Guyana 60 1, 3 110/220 2, 3, 4 A, B, D, G
—Georgetown 50 1, 3 110/220 2, 3, 4
Haiti 60 1, 3 110/220 2, 3, 4 A, B, H
Honduras 60 1 110/220 2, 3 A, B
Hong Kong 50 1, 3 200/346 2, 3, 4 C, F
Hungary 50 1, 3 220/380 2, 3, 4 C, F
Iceland 50 1, 3 220/380 2, 3, 4 C, F
India 50 1, 3 230/400 2, 4 C, D
—Ajmer direct NA 230/460 2, 3
—Ambala direct NA 220/440 2, 3
—Mumbai (Bombay City) also has 50 1, 3 230/460 2, 3
direct NA 300/600 2, 3
—Calcutta and Kanpur also have direct NA 225/450 2, 3
—Cuttack, Rajkot and Indore also have direct NA 230/460 2, 3
—New Delhi also has direct NA 250/500 2,3
—Lucknow also has direct NA 220/440 2, 3
—Madras also has direct NA 225/450 2, 3
50 1, 3 250/440 2, 3, 4
—Mussorie, Naini Tal, Simla 50 1, 3 220/380 2, 4 .
—Patna also has 50 1, 3 220/380 2, 4
and direct NA 220/440 2, 3
Indonesia 50 1, 3 220/380 2, 4 C, E, F
—Bandjarmasin, Medan, Padang, Palembang, Ujungpandang 50 1, 3 127/220 2, 4.
Iran 50 1, 3 220/380 2, 3, 4
Iraq 50 1, 3 220/380 2, 4 C, D, G
Ireland 50 1, 3 220/380 2, 4 G
Isle of Man 50 1, 3 240/415 2, 4 C, G
Israel 50 1, 3 230/400 2, 4 C, H
Italy 50 1, 3 220/380 2, 4 F, L
—Rome, Venice, Trieste, Genoa, Ancona, Bologna, Como, Cremona, Latina, Milan, Perugia, Pisa, Udine, Verona, Pescara and Chieti also offer 50 1, 3 127/220 2, 4
Jamaica 50 1, 3 110/220 2, 3, 4 A, B
Japan cmtelec_Japan 50 1, 3 100/200 2, 3 A, B, I
60 1, 3 100/200 2, 3
Jerusalem 50 1, 3 220/380 2, 3, 4 D
Jordan 50 1, 3 220/380 2, 3, 4 C, D, F, G, J
Korea         A through D, G, I, K
Kuwait 50 1, 3 240/415 2, 4 C, G
Laos 50 1, 3 220/380 2, 4 A, B, C, E, F
Lebanon 50 1, 3 220/380 2, 4 A, B, C, D, G
—Aley, Beirut, Bhamdoun, Brummana, Tripoli and Tyre also have 50 1, 3 110/190 2, 4
Lesotho 50 1, 3 220/380 2, 4 D
Liberia 60 1, 3 120/240 2, 3, 4 A, G
60 1, 3 120/208 2, 3, 4
Libya 50 1, 3 127/220 2, 4 D
—Barce, Benghazi, Derna, and Tobruk 50 1, 3 230/400 2, 4
—Sebha 50 1 230 2
Luxembourg 50 1, 3 220/380 3, 4, 5 C, F
Macao 50 1, 3 200/346 2, 3 C, D
Malaysia 50 1, 3 240/415 2, 4 G
Maldives 50 1, 3 230/400 2, 4 A, D, G, J, K, L
Mali 50 1, 3 220/380 2, 4 C, E
Malta 50 1, 3 240/415 2, 4 G
Martinique 50 1, 3 220/380 2, 3, 4 C, D, E
Mauritius 50 1, 3 230/400 2, 4 C, G
Mexico 60 1, 3 127/220 2, 3, 4 A
Monaco 50 1, 3 127/220 2, 4 C, D, E, F
50 1, 3 220/380 2, 4
Montserrat 60 1, 3 230/400 2, 4 A, B
Nepal 50 1, 3 220/440 2, 4 C, D
Netherlands 50 1, 3 220/380 2, 3 C, F
Neth. Antilles 50 1, 3 127/220 2, 3, 4 A, B, F
—Emmastad 50 1, 3 220/380 2, 3, 4 .
—St. Martin 60 1, 3 120/220 2, 3, 4
New Caledonia 50 1, 3 220/380 2, 3, 4
New Zealand 50 1, 3 230/400 2, 3, 4 H
Nicaragua 60 1, 3 120/240 2, 3, 4 A
—Bonanza, Jalapa, Matiguas, Quilali, Siuna, Telpaneca 60 1, 3 120 2, 3
No. Ireland 50 1, 3 230/400 2, 4 C, G
50 1, 3 220/380 2, 4
Norway 50 1, 3 230/400 2, 3 C, E
Okinawa 60 1, 3 100/200 2, 3 A, B, I
—Military facilities are 60 1, 3 120/240 2, 3
Oman 50 1, 3 240/415 2, 4 C, G
Pakistan 50 1, 3 220/380 2, 3, 4 C, D
Panama 60 1 110/220 2, 3 A, B, I
—Boquete 60 1, 3 110/220 2, 3, 4
—Colon 60 1, 3 115/230 2, 3, 4
—Panama 60 1, 3 120/240 2, 3, 4
—Puerto Armuelles 60 1 120/240 2, 3
Papua New Guinea 50 1, 3 240/415 2, 4 I
Paraguay 50 1, 3 220/380 2, 4 C
Peru 60 1, 3 220 2, 3 A, C
—Talara 60 1, 3 110/220 2, 3
Arequipa 50 1, 3 220 2, 3
Phillipines 60 1, 3 110/220 2, 3 A, B, C, E, F, I
Poland 50 1, 3 220/380 2, 4 C, E
—Katowice 50 1, 3 220/380 2, 3, 4 .
Portugal 50 1, 3 220/380 2, 3, 4 C, F
Puerto Rico 60 1, 3 120/240 2, 3, 4 A, B
Qatar 50 1, 3 240/415 2, 3, 4 D, G
Romania 50 1, 3 220/380 2, 4 C, F
Rwanda 50 1, 3 220/380 2, 4 C, J
St. Kitts-Nevis 60 1, 3 230/400 2, 4 D, G
St. Lucia 50 1, 3 240/415 2, 4 G
St. Vincent 50 1, 3 230/400 2, 4 A, C, E, G, I, K
Saudi Arabia 60 1, 3 127/220 2, 4 A, B, G
Scotland 50 1, 3 240/415 2, 4 C, G
Seychelles 50 1, 3 240 2, 3 G
Sierra Leone 50 1, 3 230/400 2, 4 D, G
Singapore 50 1, 3 230/400 2, 4 D, G
Spain 50 1, 3 127/220 2, 3, 4 C, E
50 1, 3 220/380 2, 3, 4
—Cadiz 50 1, 3 127/220 2, 3, 4
Sri Lanka 50 1, 3 230/400 2, 4 D
Surinam 60 1, 3 127/220 2, 3, 4 C, F
Swaziland 50 1, 3 230/400 2, 4 D
Sweden 50 1, 3 220/380 2, 3, 4, 5 C, F
Switzerland 50 1, 3 220/380 2, 3, 4 C, E, J
Syria 50 1, 3 220/380 2, 3 C, E, L
Tahiti 60 1, 3 127/220 2, 3, 4 A
Taiwan 60 1, 3 110/220 2, 3, 4 A, B, I
Tanzania 50 1, 3 230/400 2, 3, 4 D, G
Thailand 50 1, 3 220/380 2, 3, 4 C
Tonga 50 1, 3 240/415 2, 3, 4 H
Trindad & Tobago 60 1, 3 115/230 2, 3, 4 B
60 1, 3 230/400 2, 3, 4
Turkey 50 1, 3 220/380 2, 3, 4 C, F
USSR 50 1, 3 220/380 2, 3, 4 G
United Arab Emirates 50 1, 3 220/380 2, 3, 4 D, G
—Abu Dhabi !.
Ajman 50 1, 3 230/400 2, 3, 4
Sharjah 50 1, 3 230/415 2, 3, 4
Uruguay 50 1, 3 220 2, 3 C, I, L
Venezuela 60 1, 3 120/208 3, 4 A, B, H
Vietnam 50 1, 3 220/380 2, 4
—Dalat and Saigon-Cholon also provide 50 1, 3 120/208 2, 4
—Can Tho also provides 50 1, 3 127/220 2, 4
—Da Nang, Hue, Nha Trang only provide 50 1, 3 127/220 2, 4.
The country plans to convert all supply to twenty-four.
Virgin Isl (Am.) 60 1, 3 120/240 2, 3, 4 A, B
Wales 50 1, 2 240/415 2, 4 C, G
Western Samoa 50 1, 3 230/400 2, 3, 4 H
Yemen Arab. R. 50 1, 3 220/440 2, 4 A, D, G
—Aden, Little Aden, and Sheik Othman 50 1, 3 230/400 2, 4
Yugoslavia 50 1, 3 220/380 2, 4 C, F, J

# According to the Denon News (Mar/April 1992), the area east of the Fuji River receives 60-Hz current provided by Tokyo Power and Light, which bought its first equipment from the United States. The area west of the river receives 50-Hz power from Osaka Power and Light, which imported its original generating equipment from Europe.

If you need information on multi-phase power, these obsolescent of ours Africa, Asia and Oceania, Central America, Europe, Middle East, North America, South America