Why is the voltage 100-127 V in the US?

Back in 1880, Thomas Edison proposed and patented a three-wire DC electrical network, in which there were two wires +110 and -110 V and a neutral conductor. Such a network freely fed an incandescent lamp. For its operation, 100 V was needed, and Edison threw 10%, taking into account the losses during the movement of current in the wire.

Over time, George Westinghouse began to use alternating current for domestic consumers. From that moment on, the so-called “current war” began, in which Edison’s direct current was desperately losing. In 1898, people began to massively switch to the use of alternating current.

From that moment, the network standard of 100-127 V began to work. In the USA, power plants are powered by alternating current with TN-CS grounding. In this case, one phase from the secondary winding of the step-down transformer is fed into a three-wire network 120/240 V (with error calculations). Therefore, three wires come to the house of an American resident: two phases and zero. Between zero and phase, the voltage is 120 V for low-power consumers, and between phases – 240 V for powerful boilers, hobs and heaters.

Over time, Europe began to use lamps with a metal incandescent filament, which requires a voltage higher than 110 V. This is how networks with a voltage of 220 V began to appear. Electricity losses in such networks are four times lower than in 110 V networks. Why then The US hasn’t switched to 220V? The answer lies in the economic disadvantage of such reforms. Firstly, the 110-127 V network is an opportunity to combat the import of equipment, that is, the majority of Americans use devices of their own production. Secondly, electric shock at 110 V is much weaker than at 220 V (much depends on the time of exposure to the current). Thirdly, the transition to the “new” network is the cost of billions of dollars to rebuild substations and other electrical installations.

Why is the voltage 220 V in Russia?

In the USSR, as in the USA, a voltage of 100–127 V was used for a long time. However, in the mid-60s, the network began to fail to cope with an increase in the number of consumers. It was necessary to increase either the cross section of the wires or the voltage in the network up to 220 V. It became more economical to use a higher voltage. The subsequent global electrification of the country led to the fact that the 220 V 50 Hz standard became widespread not only in modern Russia, but also in all countries of the post-Soviet space.

In which countries besides the USA is the 100 – 127 V standard common?

Here is a list of countries where 100-127 V networks are used. This is worth considering if you plan to go on vacation abroad.

Country Voltage, V
Samoa 120
Anguilla 110
Aruba 127
Bahamas 120
Barbados 110
Belize 120
Bermuda 120
Bonaire 127
Brazil 127
Venezuela 120
Virgin Islands 110
Haiti 110
Guatemala 120
Honduras 110
Guam 110
Dominican Republic 110
Cayman Islands 120
Canada 110
Taiwan 110
Colombia 120
Costa Rica 120
Cuba 110
Liberia 110
Libya 127
Madagascar 127
Morocco 127
Mexico 127
micronesia 120
Antilles 127
Nicaragua 120
Panama 110
Puerto Rico 120
Salvador 115
Saudi Arabia 127
Saint Kitts and Nevis 110
Suriname 127
Tahiti 110
Trinidad and Tobago 115
Ecuador 120
Jamaica 110
Japan 100

As you can see, there are not so few countries where the voltage is 100–127 V.

What to do if you bought equipment from the USA?

Most equipment from the USA is designed to operate from 110-230 V. Therefore, if you purchased a laptop or other equipment from the States, then you just need to buy an adapter from an American plug to a European one. The issue price is 100-150 rubles.

Another thing is if the device operates exclusively from a 110 V network. A regular adapter will not help here. However, there is a solution to this problem. There are two of them:

1. Convert the power supply to work from 220 V. Most devices have a switching power supply, in which it is enough to change the capacitor (set to 400 V) and the varistor, with a breakdown voltage of 360 – 390 V. It is not difficult to find a capacitor – they are sold in any radio parts store, but with varistors they can be Problems. Of course, altering the power supply is not an easy task, but you can run an imported vacuum cleaner or other equipment without problems.

Why is the voltage in the networks 110 V in the USA, and 220 V in Russia?

2. Install a step-down transformer. It will allow the use of equipment operating from 110 V, including it in our network. However, it is important to choose a transformer of the appropriate power. Most transformers on the market are of Chinese origin, so we advise you to take them with a power margin of 10 – 20%. The cost of a Chinese device with a power of 10 W is approximately 1000-2000 rubles. At 100 W and above it will cost from 5000 rubles.

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