Перевод текста по профилю электроэнергетика

CONTENT
the introduction…………………………………………………….3
Alternative Energy – The Solution To The Fossil Fuel………………………………………………………………………………4 
1.1 The history of Alternative Energy……………………………………..4
1.2 Alternative energy is crucial to the preservation of a habital environment………………………………………………………………………6
1.3 Modular Wind Amplified Rotor Platform……………………………….7
1.4 Geothermal energy……………………………………………………..8
conclusion…………………………………………………………….9
BIBLIOGRAPHY…………………………………………………………10

the introduction
If the United States continues to employ fossil fuels for energy, the nation will ultimately become more dependent upon fuel imports from the troublesome nations of the Middle East, and we will continue to damage our precious environment. Since the United States relies so heavily on fuel from the Middle East, the U.S. is subject to the will of those quarrelsome nations in order to maintain our fuel reserve. A shortage of oil can happen at any time and would cause an energy crisis that would hinder the United States. Another reason for us to substitute fossil fuels with alternative energy sources is that fossil fuels are hazardous to the environment. In order to minimize dependency on foreign oil and to maintain a habitable environment, the United States must maximize usage of alternative energy sources such as solar, wind, hydroelectric, and geothermal energy.
Alternative Energy – The Solution To The Fossil Fuel
1.1The history of Alternative Energy
It is imperative for the United States to replace fossil fuel energy with modern Alternative Energy sources. We have evidence of disaster based on the energy crisis of the 1970s. Barbara R. Fogel has some interesting remarks on this subject:
It seemed like an inexpensive and innocent habit, but suddenly the United States found itself hooked on oil. Our very life—what we ate, how we lived, what we were, our heat and light, our jobs and cars—depended on oil, and now there didn’t seem to be enough to go around.
Fogel is saying that we had become dependent on oil, and our suppliers were the troublesome countries in the Middle East. With most of our country’s energy coming from the Middle East, we were subject to obeying the whims of those countries in order to maintain our supply of energy. Fogel comments on the effects of our dependency on the middle east for oil: In the 1970s the Organization of Petroleum Exporting Countries (OPEC) decided to drive up oil prices. The price of oil went from $2.50 a barrel to $30.00 a barrel in six years (2). This price change caused us to plunge into an energy crisis. Fogel also says that many experts believe the oil crisis will inevitably repeat itself if the U.S. does not curb its high demands for imported oil (2). This means that if we do not use some other form of energy, then the U.S. will fall into another energy crisis.
1.2 Alternative energy is crucial to the preservation of a habital environment
According to Christine A. Erwin, doctors say that fifty thousand American deaths per year are directly connected to airborne particulate matter. About one third of this pollution comes from power-plants. Therefore, if we were to produce power without producing the pollutants, then we would cut the airborne particulates by one third, thus reducing American deaths.
Solar energy is one answer to producing power without pollution. This energy is inexhaustible and available for use anywhere. Fogel says that if everyone could make full use of the sun’s light and heat, we would have about twenty thousand times as much energy as the entire world uses now . We can never use up solar energy because it is enormous and limitless. According to Erwin, solar energy is already being used everywhere in many different applications. People are using solar energy to heat pools, houses, and hot water tanks and also to produce electricity be means of Photovoltaics. This means that solar energy not only takes the place of fossil fuels for producing electricity, but can also be used for non-electric applications such as heating water or homes by capturing the solar heat. “Raw, Clean, Power” exclaims that solar energy comes at no cost whatsoever to the environment and that if we used solar energy, we would protect the environment. This means that by using solar energy, we would protect the environment from the pollution that comes from fossil fuels, thereby supporting a more habitable planet.
Another reason to use solar energy is that it does not have to be gathered or refined like fossil fuels. Erwin says that unlike its fossil fuel counterparts, sunlight is readily available and does not “…need to be explored, mined, extracted, transported, combusted, transmitted, or imported…”, making it the cleanest, cheapest to maintain, and most abundant energy source on the planet.
One way to harness energy from the sun is to use sunlight to produce heat. Fogel states that Solar One, the biggest solar power station in the entire world, collects sunlight using 1,818 giant twenty-three-foot square mirrors in the southern California desert. Solar One uses the mirrors to reflect sunlight onto a water tank to make steam for generating electricity to power over forty thousand homes. Sunlight directed by mirrors can produce heat.
Just as mirrors are used to produce heat, photovoltaic cells are used to produce electricity. According to the web site “Photovoltaics,” these photovoltaic cells are made of semiconductor materials (usually silicon) and absorb the photons in sunlight and release electrons. These electrons are captured to produce an electric current. Because of Photovoltaics, energy can be produced for free during daylight. The site “Photovoltaics” also states that we can run the current to a battery and store it until it is needed. Therefore, we can use the electricity created during the day to power appliances at night.
Wind can also be used to produce electricity. Fogel says that big windmills will make a big difference in providing energy. Windmills may not be able to replace all the energy produced by oil, but these seemingly outdated devices can cut significantly into the amount of oil the U.S. must import. By using this clean, efficient source of energy, the United States will cut down on oil imports from the Middle East and help preserve a habitable environment. According to “Popular Science,” even the most efficient wind farms cannot compete with the low prices for fossil fuels. However, a new design in wind turbines has been developed that will improve efficiency of wind turbines. “Popular Science” discusses the latest wind turbine prototype and its possibilities:
1.3 Modular Wind Amplified Rotor Platform
Weisbrich’s modular Wind Amplified Rotor Platform (WARP) looks like a stack of wheel rims laid on their sides, with a pair of turbines mounted to each of the rims concave surfaces. Wind-tunnel tests at Rensselaer Polytechnic Institute in Troy, New York, suggest that the WARP design can amplify wind speeds by 50 percent or more, because the curved surfaces channel wind toward the turbines.
This new design in wind turbines will make wind farms competitive with today’s super cheap fossil fuels.
Electricity can also be produced by harnessing the power of water in motion. Clean and safe, hydroelectric power is the electrical energy produced by “…harnessing the energy of falling water…” says hydroelectric power. Fogel tells us that hydropower is one of the cheapest sources of power in the country. In fact twenty percent of New York State’s electric power comes from hydropower and costs one-tenth the cost of oil burning methods. New York is utilizing hydroelectric energy that is cheaper and cleaner than energy from fossil fuels. If New York can benefit this much from hydroelectricity, then the entire nation could do the same or better while lowering costs and reducing damage to the environment.
Existing dams could be used for the production of hydroelectricity. The web site “Hydroelectric Power” explains that only 2,400 of the United State’s 80,000 dams are currently being used for hydropower. Therefore, creating new hydroelectric projects does not necessarily require building new dams. Many existing dams can be retrofitted with hydropower equipment so that those dams can produce electricity (Hydroelectric 3). Creating more hydroelectric projects will produce more clean and cost effective energy.
1.4 Geothermal energy
Geothermal energy, another clean source of energy, will greatly reduce the amount of oil the U.S. has to import. Energy obtained from the earth’s natural heat is explained on the web site “Geothermal Energy”:
Geothermal energy can be harnessed from the Earth’s natural heat associated with active volcanoes or geologically young inactive volcanoes still giving off heat at depth. Steam from high-temperatures geothermal fluids can be useful to drive turbines and generate electrical power, while lower temperature fluids provide hot water for space-heating purposes, heat for greenhouses and industrial uses, and hot or warm springs at resort spas.
Geothermal energy is obtained by tapping into the heat of the Earth. Augusta Goldin explains that this heat comes from molten magma deep in the Earth. Periodically, this magma rises, heats the solid rock above, and breaks through. Some of this heat is conducted to the next layer, porous rock filled with water. Then the water heats up, creating a hot-water aquifer that we can use to tap into the massive heat reserves of Earth (130). We can use the earth as the heat source for steam-driven generators because of the incredibly hot molten magma heating certain areas of the earth’s crust. This source of energy is limitless and is not hazardous to the environment.
conclusion
By maximizing the usage of clean and safe alternative resources, the United States will eliminate its dependency on foreign oil and will promote a cleaner, more stable environment. With the advanced technology of today’s world, the United States should begin a worldwide changeover to clean, renewable alternative energy sources including solar, wind, hydroelectric, and geothermal. By taking advantage of these alternative energies we can protect the world from pollution and the economic detrimental by products fossil fuels. Implementing the most up-to-date technology in the field of energy can protect the world now and insure that it will be habitable for future generations.
BIBLIOGRAPHY
1.Erwin, Christine A. “Solar Facts.” Solar Fact Sheets. Online.2. Fogel, Barbara R. Energy Choices For the Future. New York: Impact, 2015
3.“Geothermal Energy.” The Plus Side Of Volcanoes. Online.2016
4.vulcan.wr.usgs.gov/LivingWith/PlusSide/geothermal.html. 1/25/18.
5.Goldin, Augusta. “Geothermal Energy Is an Abundant and Clean Energy Source.”
6.In Energy Alternatives. Ed. Bonnie Szumsk.7.“Hydroelectric Power.” Hydroelectric. Online.8.www.westminster.pvt.k12.ct.us/science/Escience/ES%20Projects/Sa…/Hydroelectric.htm.
9. “Photovoltaics.” Pvexp. Online. www.seina.org/pvexp.htm. 1/25/2018
10.“Raw, Clean, Power.” Solar Energy Limited Map. Online.11.www.solarenergylimited.com/rawcleanpower.html. 1/25/18
12.“Wind Power Towers.” Popular Science. 14 December 2018: 14.

Residual-current device
A residual current device (RCD), similar to a residual current circuit breaker
(RCCB), is an electrical wiring device that disconnects a circuit whenever it
detects that the electric current is not balanced between the energized conductor
and the return neutral conductor. Such an imbalance is sometimes caused by
current leakage through the body of a person who is grounded and accidentally
touching the energized part of the circuit. A lethal shock can result from these
conditions. RCDs are designed to disconnect quickly enough to mitigate the harm
caused by such shocks although they are not intended to provide protection against
overload or short-circuit conditions.
In the United States and Canada, a residual current device is also known as a
ground fault circuit interrupter (GFCI), ground fault interrupter (GFI) or an
appliance leakage current interrupter (ALCI). In Australia they are sometimes
known as "safety switches" or simply "RCD". They can be found in kitchens,
bathrooms, and other places that can be wet.
Purpose and operation
RCDs are designed to prevent electrocution by detecting the leakage current,
which can be far smaller (typically 5-30 milliamperes) than the currents needed to
operate conventional circuit breakers or fuses (several amperes). RCDs are
intended to operate within 25-40 milliseconds, before electric shock can drive the
heart into ventricular fibrillation, the most common cause of death through electric
shock.
In the United States, the National Electrical Code requires GFCI devices
intended to protect people to interrupt the circuit if the leakage current exceeds a
range of 4-6 mA of current (the trip setting is typically 5 mA) within 25
milliseconds. GFCI devices which protect equipment (not people) are allowed to
trip as high as 30 mA of current. In Europe, the commonly used RCDs have trip
currents of 10-300 mA.
RCDs operate by measuring the current balance between two conductors
using a differential current transformer. The device will open its contacts when it
detects a difference in current between the live conductor and the neutral
conductor. The supply and return currents must sum to zero; otherwise, there is a
leakage of current to somewhere else (to earth/ground, or to another circuit, etc.).

RCDs with trip currents as high as 500 mA are sometimes deployed in
environments (such as computing centers) where a lower threshold would carry an
unacceptable risk of accidental trips.
In some countries, two-wire (ungrounded) outlets may be replaced with
three-wire GFCIs to protect against electrocution, and a grounding wire does not
need to be supplied to that GFCI, but the outlet must be tagged as such. The GFCI
manufacturers provide tags for the appropriate installation description.

Example

The photograph depicts the internal mechanism of a Residual Current
Device (RCD). The device pictured is designed to be wired in-line in an appliance
power cord. It is rated to carry a maximum current of 13 amperes and is designed
to trip on a leakage current of 30 mA. This is an active RCD; that is, it doesn't latch
mechanically and therefore trips out on power failure, a useful feature for
equipment that could be dangerous on unexpected re-energisation.
The incoming supply and the neutral conductors are connected to the
terminals at (1) and the outgoing load conductors are connected to the terminals at
(2). The earth conductor (not shown) is connected through from supply to load
uninterrupted.
When the reset button (3) is pressed the contacts ((4) and hidden behind (5))
close, allowing current to pass. The solenoid (5) keeps the contacts closed when
the reset button is released.
The sense coil (6) is a differential current transformer which surrounds (but
is not electrically connected to) the live and neutral conductors. In normal
operation, all the current down the live conductor returns up the neutral conductor.
The currents in the two conductors are therefore equal and opposite and cancel
each other out.

Any fault to earth (for example caused by a person touching a live
component in the attached appliance) causes some of the current to take a different
return path which means there is an imbalance (difference) in the current in the two
conductors (single phase case), or, more generally, a nonzero sum of currents from
among various conductors (for example, three phase conductors and one neutral
conductor).
This difference causes a current in the sense coil (6) which is picked up by
the sense circuitry (7). The sense circuitry then removes power from the solenoid
(5) and the contacts (4) are forced apart by a spring, cutting off the electricity
supply to the appliance.
The device is designed so that the current is interrupted in a fraction of a
second, greatly reducing the chances of a dangerous electric shock being received.
The test button (8) allows the correct operation of the device to be verified
by passing a small current through the orange test wire (9). This simulates a fault
by creating an imbalance in the sense coil. If the RCD does not trip when this
button is pressed then the device must be replaced.
Use and placement
In most countries, not all circuits in a home are protected by RCDs. If a
single RCD is installed for an entire electrical installation, any fault will cut all
power to the premises. Normal practice in domestic installations in the UK was to
use a single RCD for all RCD protected circuits but to have some circuits that are
not protected at all. Regulation introduced in 2008 dictate that on all new electrical
installations in the UK, all circuits must be protected by an RCD; however, this
does not affect existing installations.
GFI receptacles in the USA have connections to protect downstream
receptacles so that all outlets on a circuit may be protected by one GFI outlet.
Residual current and overcurrent protection may be combined in one device
for installation into the service panel; this device is known as a GFCI breaker in the
US and as an RCBO in Europe. In the US, RCBOs are more expensive than RCD
outlets.
More than one RCD feeding another is unnecessary, provided they have
been wired properly. One exception is the case of a TT earthing system where the
earth loop impedance may be high, meaning that a ground fault might not cause
sufficient current to trip an ordinary circuit breaker or fuse. In this case a special
100 mA (or greater) trip current time-delayed RCD is installed covering the whole

installation and then more sensitive RCDs should be installed downstream of it for
sockets and other circuits which are considered high risk.
Testing
RCDs can be tested with the built-in test button to confirm functionality on a
regular basis. RCDs if wired improperly may not operate correctly and are
generally tested by the installer to verify correct operation. Use of a solenoid
voltmeter from live to earth provides an external path and can test the wiring to the
RCD. Such a test may be performed on installation of the device and at any
"downstream" outlet.
Limitations
A residual current circuit breaker cannot remove all risk of electric shock or
fire. In particular, an RCD alone will not detect overload conditions, phase to
neutral short circuits or phase-to-phase short circuits. Over-current protection (fuse
or circuit breaker) must be provided. Circuit breakers that combine the functions of
an RCD with overcurrent protection respond to both types of fault. These are
known as RCBOs, and are available in 1, 2, 3 and 4 pole configurations. RCBOs
will typically have separate circuits for detecting current imbalance and for
overload current but will have a common interrupting mechanism.
An RCD will help to protect against electric shock where current flows
through a person from a phase to earth. It cannot protect against electric shock
where current flows through a person from phase to neutral or phase to phase, for
example where a finger touches both live and neutral contacts in a light fitting; a
device can not differentiate between current flow through an intended load from
flow through a person.
Whole installations on a single RCD, common in the UK, are prone to
nuisance trips that can cause safety problems with loss of lighting and defrosting of
food. RCDs also cause nuisance trips with appliances where earth leakage is
common and not a cause of injury or mortality, such as water heaters.
A dangerous condition can arise if the neutral wire is broken or switched off
before the RCD while its live wire is not interrupted. In this situation the tripping
circuitry of the RCD that needs power to be supplied will cease to work. The
circuit will look like it is switched off, but if someone touches the live wire
thinking that it is de-energized, the RCD will not trip. For this reason circuit
breakers must be installed in a way that ensures that the neutral wire is turned off
only at the moment when the live wire is also turned off. Separate single-pole

circuit breakers must never be used for live and neutral, only two or four pole
breakers must be used in cases there is a need for switching off the neutral wire.

Устройство защитного отключения
Устройство защитного отключения (УЗО), более точно устройство
защитного отключения, управляемое дифференциальным (остаточным)
током (УЗО-Д) - коммутационный аппарат, который при достижении
(превышении) дифференциальным током заданного значения при
определённых условиях эксплуатации должны вызвать размыкание
контактов. Такой дисбаланс иногда вызван протеканием тока через тело
человека, который заземлен и случайно коснулся части цепи с током. При
этих условиях может произойти смертельный удар током. УЗО
предназначены для быстрого разъединения цепи, чтобы уменьшить вред
вызванный таким ударом тока, хотя они не обеспечивают защиту от
перегрузки или короткого замыкания.
В Соединенных Штатах и Канаде, устройство защитного отключения
также известно как выключатель неисправности заземления цепи (GFCI),
выключатель неисправности заземления (GFI) или выключатель тока утечки
(ALCI). В Австралии их иногда называют "безопасные выключатели" или
просто "УЗО". Они могут быть обнаружены на кухнях, ванных, и других
местах, где может быть влажно.
Назначение и применение
УЗО предназначены для предотвращения удара электрическим током,
обнаруживая замыкание, которое может быть меньше (обычно 5-30 мА), чем
ток необходимый для стандартного выключателя или предохранителя
(несколько А). УЗО срабатывает в течение 25-40 миллисекунд, прежде чем

электрический ток вызовет фибрилляцию сердца – наиболее частую причину
смерти от электрического тока.
В Соединенных Штатах, согласно Национальным Правилам
Эксплуатации Электроустановок требует, чтобы УЗО защищающие людей от
замыканий, отключали цепь, если ток замыкания превышает диапазон 4-6 мА
в течение 25 миллисекунд. Устройства УЗО которые защищают
оборудование (а не людей), применяются с уставкой по току до 30 мА. В
Европе, в большинстве случаев УЗО применяются с уставкой по току 10-300
мА.
УЗО работает измеряя текущий баланс токов между двумя
проводниками, используя разность токов в трансформаторе. Устройство
откроет свои контакты, когда оно обнаруживает разницу в токе между
рабочим проводом и нулевым проводом. Восстановление питание
возобновляется только когда разница будет равна 0, иначе замыкание тока
может произойти где-нибудь еще (на землю или другой провод и т.п.).
УЗО с уставками по току выше 500 мА иногда применяется в условиях
(например вычислительные центры), где более низкий риск случайных
замыканий.
В некоторых странах, двухпроводные розетки могут быть заменены
трехпроводными УЗО, для защиты от удара электрическим током, в этом
случае заземляющий провод не подключается к УЗО, но розетка должна быть
с соответствующей отметкой.
Пример

На фотографии показано внутреннее устройство одного из типов УЗО.
Данное УЗО предназначено для установки в разрыв шнура питания. Его
номинальный ток 13 А, отключающий дифференциальный ток 30 мА. Данное
устройство является: УЗО со вспомогательным источником питания,

выполняющим автоматическое отключение при отказе вспомогательного
источника.
Фазный и нулевой проводники от источника питания подключаются к
контактам (1), нагрузка УЗО подключается к контактам (2). Проводник
защитного заземления (не показан) подключается к нагрузке.
При нажатии кнопки (3) контакты (4) (а также еще один контакт,
скрытый за узлом (5)) замыкаются, и УЗО пропускает ток. Соленоид (5)
удерживает контакты в замкнутом состоянии после того, как кнопка
отпущена.
Катушка (6) на тороидальном сердечнике является вторичной обмоткой
дифференциального трансформатора тока, который окружает фазный и
нулевой проводники. Проводники проходят сквозь тор, но не имеют
электрического контакта с катушкой. В нормальном состоянии ток, текущий
по фазному проводнику, точно равен току, текущему по нулевому
проводнику, однако эти токи противоположны по направлению. Таким
образом, токи взаимно компенсируют друг друга и в катушке
дифференциального трансформатора тока ЭДС отсутствует.
Любая утечка тока из защищаемой цепи на заземленные проводники
(например, прикосновение человека к фазному проводнику) приводит к
нарушению баланса в трансформаторе тока: через фазный проводник
«втекает больше тока», чем возвращается по нулевому (часть тока утекает
через тело человека, то есть помимо трансформатора).
Эта разница сразу же регистрируется следящим устройством (6),
которое приводит в действие сенсорную схему (7). Сенсорная схема
отключает питание соленоида (5). Отключенный соленоид больше не
удерживает контакты (4) в замкнутом состоянии, и они размыкаются под
действием силы пружины, обесточивая неисправную нагрузку.

Устройство спроектировано таким образом, что отключение
происходит за доли секунды, что значительно снижает тяжесть последствий
от поражения электрическим током.
Кнопка проверки (8) позволяет проверить работоспособность
устройства путем пропускания небольшого тока через оранжевый тестовый
провод (9). Тестовый провод проходит через сердечник трансформатора тока,
поэтому ток в тестовом проводе эквивалентен нарушению баланса

токонесущих проводников, то есть УЗО должно отключиться при нажатии на
кнопку проверки. Если УЗО не отключилось, значит оно неисправно и
должно быть заменено.
Использование и размещение
В большинстве стран не все цепи в домах защищены УЗО. Если для
электрической цепи установлено только одно УЗО, то при любом
повреждении будет отключаться вся нагрузка. Согласно техническим нормам
в Великобритании одним УЗО защищаются все защищаемые цепи, но не все
цепи необходимо защищать. Согласно правилу введенному в 2008 году все
новые электрические системы должны быть защищены УЗО, однако это
правило не касается уже имеющихся систем.
УЗО в США имеют связь между собой, чтобы была возможность
отключения по цепочке, таким образом все цепи могут быть защищены
одним УЗО.
Защита от статочных токов и сверхтоков может быть осуществлена
одним устройством, устанавливаемым на специальной рабочей панели. Эти
устройства известны в Европе и США как УЗО-Д. В США УЗО-Д более
дорогие чем простые УЗО.
Для питания УЗО необходима лишь одна цепь питания, при условии
что оно правильно установлено. Исключением может быть трансформатор
тока, заземляющий систему, так как их сопротивление может быть выше, и
при замыкании значение тока будет недостаточным, чтобы сработал рабочий
выключатель или предохранитель. В этом случае применяются специальные
УЗО с уставкой по току 100мА (или выше), которые защищают всю систему,
а затем более чувствительные УЗО которые должны защищать цепи с
большим риском удара током.
Тестирование
УЗО может быть протестировано нажатием кнопки “тест”, для
проверки его работоспособности. Если УЗО присоединено неверно, то оно
может не сработать и как правило его настройку осуществляет монтажник,
используя вольтметр, соединив рабочую фазу с землей по внешнему контуру.
Ограничения
УЗО не может полностью исключить риск поражения электрическим
током или пожара. УЗО не реагирует на аварийные ситуации, если они не

сопровождаются утечкой из защищаемой цепи. В частности, УЗО не
реагирует на короткие замыкания между фазами и нейтралью. Должна
обеспечиваться защита от тока перегрузки. Выключатель который
объединяет в себе функции УЗО и защиты от тока перегрузки должен
обеспечивать защиту от обоих типов повреждений. Они известны как RCBO
и выполняются в 1, 2, 3 и 4х полярной конфигурации. RCBO обычно
разделяет цепи небаланса и цепи с током перегрузки, но имеет один
размыкающий механизм.
УЗО поможет защитить человека от удара электрическим током, когда
ток течет через человека из фазы на землю. УЗО также не сработает, если
человек оказался под напряжением, но утечки при этом не возникло,
например, при прикосновении пальцем одновременно и к фазному, и к
нулевому проводникам. Предусмотреть электрическую защиту от таких
прикосновений невозможно, так как нельзя отличить протекание тока через
тело человека от нормального протекания тока в нагрузке.
В результате установки только одного УЗО могут возникнуть
проблемы, т.к. при срабатывании защиты будет проходить потеря освещения
или размораживание пищи. УЗО также доставляет неприятности с
устройствами где утечка на землю является обыкновением, а не причиной
повреждения, как например в водяных нагревателях.
Опасная ситуация может возникнуть когда нулевой провод поврежден
или отключен перед УЗО, а рабочая фаза не отключена. В этом случае ток
необходимый для питания УЗО не будет поступать, и оно не будет работать.
Цепь будет выглядеть отключенной, но если кто-нибудь коснется рабочей
фазы, думая, что она отключена, то УЗОР не сработает. По этой причине
выключатель устанавливается таким образом, что нейтральный провод
отключается только тогда, когда рабочая фаза тоже выключена. Разделение
однополярного выключателя никогда не используется для нулевой и рабочей
фазы, только 2 или 4 полярные выключатели используются в случаях, когда
есть необходимость переключения нулевого провода.