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Why doesn't the US use 230V the way (almost) everyone does?

TechEkspert 92853 122
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  • Why doesn't the US use 230V the way (almost) everyone does?
    The question of the 120V 60Hz AC power standard in the USA is a common cause of confusion. First of all, not only the USA uses 120V in its home electrical system. There are also differences in "higher" supply voltages depending on the country, there are standards of 200V, 220V, 230V, 240V, 50Hz / 60Hz.

    In addition, almost all buildings in the USA have a 240V AC power connection. 240V AC power is also available on selected sockets in the house. Sockets with available 240V AC supply supply energy to receivers that require more power (washing machines, ovens). Low-power receivers, such as lamps, laptops, chargers, do not need access to 240V sockets and use 120V AC power.


    For those surprised by the fact that 240V is available in the 120V system - short explanation: the secondary side of the transformer feeding the building has a tap in the middle of the winding connected to the neutral wire. The neutral conductor is grounded in the fuse box, while the two extreme ends of the winding supply power to the two phase conductors (voltage phases displaced by 180 ° relative to each other). In most cases, one of the phase conductors and the neutral wire are used, supplying 120V AC voltage, which allows for 1800W power consumption (15A 120V). For devices with higher power, both phase wires are used, which allows you to work with a voltage of 240V and power consumption of 3600W (15A 240V). 240V can be supplied to specific sockets or led permanently to the device terminals.

    The historical reason for the fact that the USA stayed on 120V is the carbon filament lighting system used in the past. Before the introduction of tungsten filament lighting, a large 120V power supply infrastructure had already been built. 120V AC power remained the standard.
    The US has a very large power grid and nothing indicates changes to the current standards.



    The UK is one example where the power grid has been rebuilt. Fuses are built into the plugs instead of connecting each socket separately to the switchgear and protection. This is the reason why the nests in the UK are different compared to the rest of Europe.

    Why doesn't the US use 230V the way (almost) everyone does?

    Do we need a uniform global standard for supplying end user loads?

    It makes no sense to change everything just so that the same power standard is used everywhere. Such changes would be very costly. Many devices (especially with a switching power supply) accept a voltage range of 220-240V AC, sometimes even 90V-240V. In some devices, you can find switches that allow you to set a specific supply voltage. It makes sense to standardize the exchange of energy between the transmission systems of national energy networks, as well as transmission networks, so that foreign equipment used in the transmission network can be used more easily.

    Source:
    http://www.electronicproducts.com/Power_Produ...use_220V_like_everyone_else_in_the_world.aspx

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  • #2
    leonow32

    Level 30  
    Ehhh, these Americans ... have to do everything their own way ;)
  • #3
    TechEkspert
    Editor
    In the USA, the distribution network also looks a bit different.
    In Poland, we are used to a transformer station to which 3f 15kV is connected and 3f 400V (phase-to-phase), 3x 230V (against the neutral wire) are distributed further. 400V is distributed overhead or via earth cable to consumers.
    A transformer in urban areas can be located in a smaller or larger building or container, sometimes it is built into the structure of a residential or office building.
    In less urbanized areas, the transformer is usually placed on a pole, to which 15kV is connected overhead (sometimes via an earth cable), similarly 400V is supplied overhead or sometimes via an earth cable. We often come across transformer capacities of 100kVA, 250kVA, 400kVA, 1MVA.

    For the USA in open spaces, transformers with a capacity of several to several dozen kVA in the form of a barrel placed on a pole are characteristic: https://en.wikipedia.org/wiki/File :P olemount-singlephase-closeup.jpg



    An unusual, for our conditions, idea is SWER (single wire earth return), i.e. transformers on poles in an open space, to which one wire with an alternating voltage of several kV has been led. The other terminal of the primary winding is grounded. The secondary winding supplies low voltage household consumers. Thus, the circuit between the primary winding of the distribution transformer on the pole and the secondary winding of the isolation transformer is closed through the ground.

    Hence, the spectacular explosions and sparks of sparks, sometimes seen in the movies, are seen when a pole with a distribution transformer is knocked over, or the power line is broken or overloaded.

    Here are recordings of real situations:



    Oil flooded with the transformer can set fire to everything in the area quite quickly when ignited
  • #4
    oskar777

    Level 26  
    If it's such a ticking bomb on a pole, why won't they give it up? After all, it can set off the surrounding buildings with smoke, and when there is such a thing in the forest, I don't want to even think about it.
  • #5
    nici
    Moderator Chiptuning
    Great and factual article. By the way, I was curious why they have a different tension.

    Congratulations!
  • #6
    TechEkspert
    Editor
    oskar777 wrote:
    If it's such a ticking bomb on a pole, why won't they give it up? After all, it can set off the surrounding buildings with smoke, and when there is such a thing in the forest, I don't want to even think about it.


    Perhaps the point is that the network is easy to scale and change quickly.
    They run the 2-19kV network with an overhead cable, then, where necessary, they install a transformer on a pole and lead low voltage to the apartments.
    When new customers or demand for more power appear - they add more transformers or replace them with a transformer with a higher power.

    My subjective feeling is that the power grid in Poland is more standardized and perhaps a bit more secure. Perhaps the network in Poland is slightly scaled in places (e.g. too much transformer power in the substation), but I prefer more 400V 3f branches than having a line outside the window with a voltage of several kilovolts and a transformer on a pole filled with oil.
    Small container stations near the building have recently appeared in housing estates, as opposed to popular buildings with a larger transformer powering several blocks in the area.

    The effects of the storms show that consumers in less urbanized areas with an extensive 15kV network and transformers on poles (just like in the USA, only higher power and less dispersed structure) suffer the most.
    Cities usually suffer less from the effects of storms, as 15kV / 0.4kV stations are usually powered by a ground cable (often in a ring). Ev. damage to 0.4kV overhead lines disconnects individual groups of consumers.

    Of course, we are looking at the recipients of groups IV and V
  • #7
    Tommy82
    Level 41  
    @ oskar777
    That's the atmosphere. And more seriously, it is something for them that they have always dealt with, i.e. the existing state. Maybe they don't even see it in such terms. Because reversing the case, the voltage of 120 V seems to be safer, why do we use 230?

    @TechEkspert

    Gale is a total of one pic of which lines are damaged.
    On the other hand, many small transformers are certainly more expensive (sum sumarum), but if necessary, it is always better to replace a few small ones than one big one, it's easier to have a number of small ones in stock.
    In our case, if basically anything, basically to the level of the transformer in the area, the whole area has no electricity
    and there is always one level of failure that is dispersed so the neighbors have electricity.
    And you can always get some help.
  • #8
    andrzej lukaszewicz
    Level 40  
    And why the angola and a half of the world drive on the left side of the road, the track width varies in many countries, the inch and metric system, TV and video systems, etc. are still used.
    As you can see, the same things could be done in many ways.
    Power supply with voltages of 110, 115, 127 V is used in many countries (Libya, Indonesia, Saudi Arabia and others), especially in Central and South America. Over 120 million people in Japan have 100VAC power and they do it too.
  • #9
    janusz2k
    Level 14  
    In the USA, 3-phase voltage is also available - e.g. for three-phase motors, but not used in households, only in factories and manufactories.
  • #10
    rafbid
    Level 33  
    Tommy82 wrote:
    why do we use 230?
    We have adapted to the values of "European"
    janusz2k wrote:
    3-phase voltage is also available in the US
    With what tension?
  • #11
    hobbyelektronik
    Level 27  
    It should be mentioned that when using 230V voltage, we save on copper, the wire cross-sections are half smaller.
  • #12
    a_noob
    Level 23  
    The energy infrastructure in the US is old, neglected and backward. They have enormous losses in the transmission of electricity, however, changing the entire network is nowadays associated with too high costs (excluding consumers' receivers). That is why they sit and watch as the mass of energy goes to heat the wires and transformers before it reaches the recipient.
  • #14
    michalko12
    MCUs specialist
    a_noob wrote:
    The energy infrastructure in the US is old, neglected and backward. They have enormous losses in the transmission of electricity, however, changing the entire network is nowadays associated with too high costs (excluding consumers' receivers). That is why they sit and watch as the mass of energy goes to heat the wires and transformers before it reaches the recipient.

    Every 10-20 years they should increase the voltage by a few% so that it slowly reaches a reasonable value. Such periods allow old equipment to wear out, and new equipment can already be manufactured for higher voltage with greater tolerance. The replacement of infrastructure sooner or later has to happen anyway, because it is also getting old and worn out.
  • #15
    a_noob
    Level 23  
    michalko12 wrote:
    Every 10-20 years they should increase the voltage by a few% so that it slowly reaches a reasonable value. Such periods allow old equipment to wear out, and new equipment can already be manufactured for higher voltage with greater tolerance. The replacement of infrastructure sooner or later has to happen anyway, because it is also getting old and worn out.

    There is no shortage of stout heads like ours ;) but someone would have to turn these ideas into action, and that's a different story.
  • #16
    Tommy82
    Level 41  
    My great-grandmother, who survived most of the wars of the twentieth century (almost all because when the Wright brothers flew and the Titanic sailed, she was already in the world) had such a rhyme I was too small to remember it in full Janek died near Lviv, not near the ravine) the point was that the cat harassed the mice:
    And the learned mouse arises:
    Tie a bell to his tail.
    The punch line was so rhymed: who would do it?
  • #17
    koczis_ws
    Level 27  
    Tommy82 wrote:
    @ oskar777 ...
    On the other hand, many small transformers are certainly more expensive (sum sumarum), but if necessary, it is always better to replace a few small ones than one big one, it's easier to have a number of small ones in stock. ...


    There is one more thing. As I remember from the electrical engineering lesson, the efficiency of electrical machines increases with their power.
  • #18
    vodiczka
    Level 43  
    adria5n wrote:
    And which electric kick hurts more?
    What do you think? :)
    The lower the voltage, the less dangerous the current and the less painful the sensation after close contact.
    At home, until 1960, I had a voltage of 120V and despite kicking several times, I did not feel respect for the current.
    Until my grandparents were fond of 220V.
  • #19
    oshii
    Level 24  
    koczis_ws wrote:
    There is one more thing. As I remember from the electrical engineering lesson, the efficiency of electrical machines increases with their power.

    As long as the US has the cheapest energy in the entire civilized world, no one will care if it is possible to cut off a few percent of efficiency in a few places.
  • #20
    mefist
    Level 11  
    TechEkspert wrote:
    depending on the country, there are also differences in "higher" supply voltages, there are standards of 200V, 220V, 230V, 240V


    In my socket there is still 252V ;)
  • #21
    Sofeicz
    Level 18  
    andrzej lukaszewicz wrote:
    Over 120 million people in Japan have 100VAC power and they do it too.


    To make it funnier, part of Japan has a 50 Hz mains frequency and part 60 Hz.
    At the junction of these areas, gigantic inverters operate to match these frequencies.
    This is just a gang ride.
  • #22
    michał_bak
    Level 18  
    oshii wrote:
    As long as the US has the cheapest energy in the entire civilized world, no one will care if it is possible to cut off a few percent of efficiency in a few places.

    It's true, the same is with cars that had such a capacity that it could make your head spin.
    Americans have a specific attitude to the environment, they see a threat to the Białowieża Forest, they do not see what they have led to, e.g. with the Hoover Dam.
  • #23
    amator2000
    Level 24  
    I like English plugs the most - industrial design and this beautiful fuse in all of them.
  • #24
    kkknc
    Level 43  
    michał_bak wrote:

    Americans have a specific attitude to the environment, they see a threat to the Białowieża Forest, they do not see what they have led to, e.g. with the Hoover Dam.

    Because at every step, they know what progress this is and what's more, the free market that helped break Rockefeller's monopoly on lighting kerosene for homes. And it was so powerful that it could overthrow the entire United States. That is why Roosevelt opened the dam so solemnly.
  • #25
    nici
    Moderator Chiptuning
    amator2000 wrote:
    this beautiful fuse in each


    and I can already see how in Poland, our citizens, after burning one, are artfully facing whatever they can:]
  • #26
    hobbyelektronik
    Level 27  
    Even today, the USA generates electricity at 25, 30 and 40 Hz for some applications, it should be emphasized that North America does not
    there is still formal acceptance of the 60Hz frequency as a standard quantity. Unlike Europe, where the 50Hz frequency has been formally approved by treaty between individual countries, in North America it is used only by consensus.
  • #27
    bernanio
    Level 14  
    when I read it a little incredulously,
    the truth is that we have an average of 15kV in Poland, sometimes even in some places 30kV, 10kV, 6kV, 3kV
    MV outgoing feeders at stations have the following protections: overload (low current, long time), short-circuit (high current, short time (0.1 to 0.3s)), earth fault (conduction, admittance)
    In the case of overhead lines, the auto reclosing cycle is set once or twice in case of overload or earth-fault protection.
    In the case of American lines, there is no such diagnostic option, I do not even see the option of checking whether a given line is overloaded or earthed, since the power supply is 1 medium phase and a hoop by the pole :P )
    However, in "backward" PL you have, for example, 40kW of connection power as standard
  • #28
    koczis_ws
    Level 27  
    Today on TV I watched the program "Death in 1000 Ways" (American), in which a girl was shown walking barefoot on a wet pavement, touched a metal pole buried in the ground and was electrocuted to death. I'm terribly curious how is this possible? And if so, it's scary to go to America :D
  • #29
    bernanio
    Level 14  
    A phenomenon such as step voltage occurs, the potential difference is deposited along the length of the earth.
    in Poland it is much safer, because each current leakage through the ground from the MV or HV line is treated as an earth fault and the line is switched off. However, this will occur for about 0.5 seconds before the earth fault protection is triggered
  • #30
    akajarz
    Level 23  
    koczis_ws wrote:
    Today on TV I watched the program "Death in 1000 Ways" (American), in which a girl was shown walking barefoot on a wet pavement, touched a metal pole buried in the ground and was electrocuted to death. I'm terribly curious how is this possible? And if so, it's scary to go to America

    It is possible, because if some power is taken from the "barrel" transformer, the voltage is deposited on the ground, which is not perfect after all. And God forbid this grounding will spoil this misfortune 100% it is. It is unthinkable for us, but the Americans are a power, they are not afraid of anything, as you can see even electricity.