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

As I wrote, some installations in the USA are very old ... And it is true that there is often a two-phase system in flats, but in all newer installations three phases are introduced because the difference in costs is small and the benefit is large and an air conditioner in each window.
In Poland, in the 1960s or even the 1970s, there were two-phase installations, often there were such installations in welding or blacksmith workshops, where transformer welders powered from 380V were used. There were even special Polish two-phase meters. I even remember such an exercise from the Measurement Laboratory at the Technical School: "checking a two-phase counter".
All professional equipment from the USA - if it is more powerful - has a 220 / 230V supply voltage. I used to install American-made transmitters in Poland, which used impulse power supplies and required 220 / 230V. There were always several power supplies - often in a redundant system - e.g. 6 units, and they could be connected by two for one phase or in any other systems.
Professional "general cargo" is most often equipped with 110 / 230V impulse converters.
As an interesting fact, it is not only in the USA that the voltage of 127V is used - or was it used. Back in the 1980s, in the Siberian part of the USSR, I saw local power plants (in places away from the main power lines) operating on original American power generators straight from Land-Lease or UNRRA transports. Only the rotational speed of the engines was changed from 1800 to 1500 rpm so that the generator was 50 Hz, not 60 Hz.
Therefore, Soviet electronic equipment was almost always equipped with voltage switches.

So it can be said that the main thesis has fallen? They have 230V. By the way, you can perversely give the answer that it is on purpose, as long as the sinkhole does not connect a washing machine with a heater, just call an electrician to the socket. Kasiorka.

95% of washing machines in the US have a dual water supply - separate hot and cold. Another thesis failed

Regarding the symmetry of the phase load in the case of single-phase or two-phase connections: a fairly common way to equalize the consumption of individual phases was to use MV / LV transformers with a secondary winding associated in a zigzag. In Poland, such systems were used in the past, now I do not see such a solution anymore, at least in the installations I have contact with. Perhaps I am looking for a little. Such transformers are usually marked with the symbol Yz5.

The standard transformer circuit has a star secondary winding with the central point of the windings grounded.
A transformer with a zigzag winding has not 3 but 6 secondary windings (LV) of about 74V each. Each of the phases is equipped with two secondary windings and were connected such that the "hot end" of the first winding of the first phase is connected to the "cold end" of the second winding of the second phase. As a result of such a connection, each phase in the 127V system loads two phases evenly, while in a 220V (two-phase) connection, one of the phases gives 2/3 of the power and the other 1/3 of the power.

Such a transformer has / had a special star mark with broken ends on the housing. The disadvantage of the system is the lack of parallelization of transformers or supply points.

Currently, such solutions are no longer used, but in the 1940s or 1950s in the USA it was quite common.
And as my colleagues write: two phases as standard, three in newer installations.

Echhh, nice those American dry transformers ..Welded core, but it is not important, wound with an aluminum flat bar with a flock of taps on the primary and secondary windings. You can adjust the voltage to the volt.

I will add for the curious:
https://pl.wikipedia.org/wiki/Transformator_energetyczny

American pole-mounted transformers almost always have aluminum windings to keep them as light as possible. In a "normal" transformer, the copper winding is more than half the mass.

irekr wrote:

With this voltage of 120 V and reversed by 180 degrees, gentlemen, that's an exaggeration ...
As an electrician I was a bit tinkering overseas (they honored our SEP qualifications!) And today almost every apartment has three phases with a phase voltage of 127 V, which gives 230V inter-wire voltage

Sorry, but somehow I completely can't fit it into reality. 120 / 240V split-phase is standard in 99.9% of houses and apartments, both old and new. Sometimes somewhere you can find some old 2-wire connection giving only 120V, but they were created before the war and someone renovating the house always modernizes it according to current standards, i.e. 120 / 240V with 200A main protection (for the last several decades, basically only this is in relation to changed, it used to be 60, 100, 125, 150A ...).

In buildings such as shops, services, small production 120 / 208Y is common, there is also a 120/208 high-leg delta (more in places where three-phase motors are mainly used). In homes, the first system is not applicable because it is impossible to get 240V in it, and all household dryers, cookers, heating and air conditioning are designed for this voltage.

In the meantime, I found information about 5kV stations used in Poland (specifically in Warsaw) before the 15kV MV networks became popular (due to the increasing demand for power):
https://pl.wikipedia.org/wiki/Transformator_kioskowy_(kiosk_elektryczny)
by Wikipedia's MV network with a voltage of 5kV was operated until 1977.

According to of other sources in Warsaw, there was a low voltage network of 125V and 122V (5kV / 125V stations):
http://oelka.bikestats.pl/926416,Przedwojenne-stacje-transformatorowe.html
and an interesting fact, an underground transformer at Zbawiciela Square.

I will add that there are 20kV stations in the Suwałki Region.

The voltage of 20 kV and 40 kV are new MV standards that are introduced in the EU. They will replace 15 and 30 kV networks.

irekr wrote:

They will replace 15 and 30 kV networks.

How? It is enough to replace transformers or need a complete line replacement because (taking into account the safety margin) it will not withstand a voltage increase of 33.3%.

@irekr Is it standardization or the real need for more power?

@ p.obelix are there any visible differences in the standards of their construction?

I do not know the reasons why a new amount of tension is introduced. There is a text about it on the website www.iec.ch but I haven't gotten into the content yet. Anyway, it concerns Europe and the topic is about the USA.
I can only guess that it is about making it possible to transmit more power than is currently the case while leaving the infrastructure. After all, 15 kV equipment will easily carry 20 kV, at least the newer one ...

irekr wrote:

After all, 15 kV equipment will easily transfer 20 kV,

I just don't get it. Is the newer equipment manufactured with such a large margin of safety that a permanent increase in tension by 33.3% is consistent with the art of engineering?

For example, if the equipment is designed, for example, with a 100% safety margin, it is known that it will move, but at the same time the safety margin will shrink.
Maybe the new equipment is already being designed and built for higher voltage by anticipating an increase in voltage?
After all, the change of nominal voltage from 15 to 20kV is not a change from 220 to 230V (increased by less than 5%)

Generally, designers have been advising to design cables with insulation for 20 kV (12/20) for MV lines for some time, despite the fact that the line operates at 15 kV (the cost is none and the potential savings are huge in the future). For example, NKT produces XRUHAKXS in 6 / 10kV and 12 / 20kV versions with nothing in the middle.
Equipment such as circuit breakers, switchboards, etc. are also often today in versions for e.g. max. 24 kV despite operating in a lower voltage network. Hence, in the newer networks there should not be any big problems with the transition to 20 kV (except for the replacement of transformers). In overhead networks, insulators have a spare, and their possible replacement is not a construction of the line from scratch.
It is worse with old cables in oil-paper insulation, especially in urbanized areas (and they are mainly there) or overvoltage limiters in overhead lines (although these sometimes have to be replaced, it is also not a property).

And by the way of this American SWER, it excludes the use of differences ... linden in its entirety.

SWER is not used in low voltage networks. In the USA, the standard is the TN-C system in the supply network and TN-S in the receiving installation, with the PEN distribution point (i.e. our equivalent of this cable because the North American nomenclature specifies it differently) in the main switchboard of the building or at the meter (different regions differ traditions).

In installations, differentials are used as much as possible, but not in all circuits because there is no such need (just like in Europe).

michcio wrote:

TN-S in a receiving installation, with a PEN distribution point (i.e. our equivalent of this cable because the North American nomenclature specifies it differently) in the main switchboard of the building or at the meter (customs differ in different regions).

and not TT by?

In the main switchgear of the facility, the protective and neutral busbars are connected with each other by a bridge or it is simply one common bus (while all subsequent switchgears supplied from the main switchboard must already be supplied with a cable with a separate protective and neutral conductor, and of course these busbars must be separated) .
The exception is the situation in which the main switchgear is powered by a cable with a separate protective and neutral conductor - then these conductors usually originate from the common busbar / terminal near the meter, then the busbars are separate everywhere.
In a typical installation, an earth electrode is made in the form of copper pins driven in near the connector at a distance of a few feet from each other, connected by a copper wire with a protective-neutral wire (there it is simply "neutral") in the meter base, along the way a rail is mounted to which elements such as a braid of coaxial cables from the cable or telephone system elements will be connected (all such installations are entered into the building in one place together with the electrical supply).

(photo from the internet)
You can see a typical meter base - the energy meter will be inserted into the knife terminals on the phase conductors and the whole thing covered with a metal mask with a round hole for the meter, the neutral wire (the one in the middle, you can see the earth electrode connected to it) does not pass through the meter (because it does not have to be) - here it is the cable braid. The cable is most likely 4/0 or 107 mm2 (it must withstand 200A) and it is of course aluminum.

In this way, the fact that the neutral and protection circuits are metallic excludes the TT system.

I just add that all American meters have current measurement on both wires, regardless of whether it is an "old type" 127 V or two-phase measurement as shown in the picture above.

And differentials have been mandatory in bathroom installations for several years. So the scene in the movie, when a hair dryer falls into the bathtub with a delinquent (on the inherent long and twisted cord) is no longer relevant ....

The last two posts contain conflicting information. Either the zero wire passes through the meter or it is released sideways as shown in the picture.

Quote:

all US meters have current measurement on both leads

jaszczur1111 wrote:

The last two posts contain conflicting information. Either the zero wire passes through the meter or it is released sideways as shown in the picture.

Quote:

all US meters have current measurement on both leads

Maybe the measurement is on a current transformer?

British plugs may be safe and nice, but try to take the charger somewhere with you. Pins stick out, scratch (e.g. tablet screen), wipe backpacks - a tragedy. European plugs are small and soft, American plugs have pop-up pins. Only the British are "not transferable".

But back to the tensions in the US. I have something to add regarding another large American country, but in the southern hemisphere - Brazil. It is just a rolling ride there. Frequency 60Hz. But the voltage - it depends on the building and installation. Maybe 110 or maybe 220 (230) - free American. Nests? Theoretically there is a new standard, the higher voltage - but not always - depends on the installation entering the building. The dimensions of the plug resemble a European flat and it fits without any problems. this center pin is ground. Such something can be a socket and a light switch, then the two extreme ones are key switches. And we get an outlet by the door. It is unnecessary and inconvenient to use no one cares.



But something else. I saw the moan that central element flew out and between the light switches we have the bare power plate. This is already a light crime.

Other types of sockets, universal: slots for American plugs, holes for pins with European spacing, but a bit too tight for my EUR / UK adapter to enter. I used the American. Tensions? as above, but I was told that someone carved such an installation: the slots are 110 and the pins are 220V.




Moreover, the last thing, but very interesting in the context of energy saving. Brazil has a lot of sun, it is very warm outside, so the natural situation would be to use solar collectors to heat water - an ordinary barrel painted black would suffice.

But no, it is better to install electric water heaters for showers:



Maybe it's even more interesting elsewhere, I've only been to Rio and Macae.

These sockets in the first photo are also used in Switzerland.

And the American meters have two current coils and a measurement on two wires. The neutral / neutral wire is not needed for the measurement if there is line-to-line voltage. It's just a matter of setting the electromagnets on the dial or software in electronic meters ...

Our old two-phase meters - in some versions - also did not use "zero" for measurement, the voltage coil was powered from 380V. I had such a meter in my hands in the measuring laboratory in the technical school. A long time ago but it was ...

So I understand that the measurement takes place on 2 of 2 phases and zero comes directly. No contradiction. Thanks.

sanfran wrote:

But no, it is better to install electric water heaters for showers:

Hahahaha, E sabi, Amigo It's a curiosity with these heaters. The heating spiral is DIRECTLY immersed in the water! I recommend RCD for this In Suriname there is an identical brothel in the network as in Brazil, the tensions are the same, the network is TT by definition, and machines are mainly imported through the former metropolis - the Netherlands - from Europe. So there is no shortage of work ($$$) Regards.

So when we break zero, we have a dead body ?!

I don't suppose. As one of the colleagues noted, an earth electrode is made for each connection, the parameters of which are checked periodically. Additionally, its resistance cannot be higher than 0.5 ohms - in Poland 1 ohm. The condition for admission to operation is efficient earthing and no one will risk it, the energy company is responsible for it. In addition, the neutral conductor has a really large cross-section.

Even so, their installations can leave a hair on the head.

Frog_Qmak wrote:

So when we break zero, we have a dead body ?!

With an ungrounded heater - yes. There have been such accidents. This, however, has 2.2kW at full power and it happened that it could burn N by itself. Now they have banned these razors, but still use them in favelas and in the jungle As a curiosity, the Brazilians brought this "Mierde" from Brazil to Suriname, and that generally EBS (Electrobedrijf op Suriname - Power Plant) forced the installation of RCDs with penalties a few years ago, it was fun in the Brazilian district. Please - assembly drawing of this "miracle".

In the 90's you could buy an even better patent in bazaars from the Russians. Devices put on the tap, made of plastic inside 2 central and outer electrodes set so that the zero is closer to the water outlet. It was important
"polarity" and connection to a metal, grounded water system is mandatory. I had it in my hands but never checked if it worked. You could not turn off the electricity. According to the instructions, the water boiled and stopped heating.
It looked very similar. No switch, thermostat, non-dismountable. Contemporary buzała, if you know what we are talking about.

ps. I hope the moderator will let this off-topic post. the discussion deviated significantly from the main topic, but it seems to have been heavily exploited.