A Division In Voltage Standards

During my recent trip to Europe, I found out that converters were not as commonly sold as adapters, and for a good reason. The majority of the world receives 220-240 V single phase voltage at 50-60 Hz with the surprisingly small number of exceptions being Canada, Colombia, Japan, Taiwan, the United States, Venezuela, and several other nations in the Caribbean and Central America.

While the majority of countries have one defined plug type, several countries in Latin America, Africa, and Asia use a collection of incompatible plugs for different wall outlets, which requires a number of adapters depending on the region traveled.

Although there is a fair degree of standardization among most countries with regards to the voltage used for domestic appliances, what has caused the rift between the 220-240 V standard and the 100-127 V standards used in the remaining nations?

Typical Residential Power

Mains power (or grid power, wall power, domestic power) refers to the general purpose AC electric power supply that is accessible in homes and businesses, typically for domestic appliances. Mains power can differ by voltage and frequency, and of course trying to use an incompatible value runs the risk of destroying your appliances.

Most commonly, power is delivered to a household in two or three wired contacts — a line wire (the hot contact carrying the AC between the power grid and the home), the neutral wire (completes the circuit and carries AC), and the ground wire (connects the equipment to the earth ground to protect against electric shocks).

The value for the voltage is the measurement on a single hot wire with respect to neutral or ground. Given the resistance in household wiring and the distance of extension cords used for domestic appliances, this value usually drops by the time it reaches an appliance, which is one of the reasons for values other than the mains voltage to be used for appliance ratings.

We’ve previously written about power transmission equipment and the transformers you’ll find on typical utility poles to provide residential feeds from two- or three-phase utility lines.

Where Did These Voltage Standards Originate?

The first large-scale central electric power plant was started by Thomas Edison in 1882, providing direct current (DC) at 110 V for 968 light bulbs in London. This was considered to be a “safe” voltage for consumers to use and was also the best voltage for the filaments used in his lightbulbs.

After his London plant, AC systems began to emerge in the United States, using transformers to step down higher voltages from distribution. Edison responded by patenting a three wire distribution system in 1883 to provide greater versatility for users, which soon gave way to the War of Currents (there was actually a recent motion picture released on the topic).

Within the United States, after AC proved superior, Westinghouse Electric adopted the 110 VAC 60 Hz standard. European power companies, on the other hand, pushed the voltage to 240 V in order to improve distribution efficiency. At this point, insulated wires and safety measures in power distribution were sufficient that 240V was no longer considered dangerous for users, leading to the widespread adoption of the 240 VAC 50Hz standard.

Depending on the connection to the ground, wetness or resistance of their skin, surface area of their contact, and duration can all play a role in determining the real safety concerns for a person dealing with electrocution. But in modern times, circuit breakers, GFCI outlets (ground-fault circuit interrupter), and AFCI outlets (arc-fault circuit interrupter) have done much to address the electrocution and fire concerns of mains power.

This is the System We Have

This is the way things are and the way they shall be. There aren’t any plans for major changes to unify standard mains internationally. Converting from one system to another would be prohibitively expensive and there is no driving force to do so. Modern electronics manufacturers have for the most part made this a non-issue by designing power supplies that will happily function on either 240 V or 110 V, needing only a simple converter to make the wide array of outlet types play nicely with your country’s chose standard.

For devices that use the AC power directly, the plug type helps to ensure appliances relevant to the market are what is being sold. In countries like the United States, when the higher 240 V standard is needed an outlet is wired using two hot legs to obtain 200-240 V from a power grid system designed to deliver 110 V.

150 thoughts on “A Division In Voltage Standards

        1. Just before we lost our last Coal Power plant in Canada, It had 500,000 Volts coming out of one of the generators.
          That was cool just watching the mains in the Switching yard turn on N off.
          It was like being beside a lighting strike. So So cool and loud.

          1. You may mean the last coal-fired plant in Ontario. There are still coal burners in Alberta, Saskatchewan and Nova Scotia, plus one in Manitoba which can only be run in emergencies.

          2. The Nanticoke site. Good riddance. Four gigawatts of coal-sourced power at a single site made an awful mess of the neighbourhood. Now they use the space (and the existing connecting power lines) for a relatively pitiful solar farm and a few wind turbines, with their crappy capacity factor and zero baseload capability. A perfect site to plop down a few CANDUs, and they missed the opportunity.

            Note that the generators themselves didn’t / don’t put out 500 kV. That would require ridiculous amounts of insulation inside the generator, which would take up space better used for copper windings. No, they typically put out only 5-10 kV (at many kiloamps), and run immediately to transformers before going out to the switchyard.

      1. Yeah, those devils are scary! The Amsterdam Safety Museum made a bunch of nice posters of them. Here’s a picture of one of them: https://i.pinimg.com/originals/bf/aa/c5/bfaac5549fc12ee018cdcf15b5fb4c29.jpg
        [translation: Danger lurks on bare wires]
        But there are no devils in our domestic power lines. Instead, you have little electricity snakes: https://live.staticflickr.com/4076/4753872989_a465d8245e_b.jpg
        [translation: Bad materials are the cause of many accidents. Come to the Amsterdam Museum of Safety to see proper, safe materials!]

        1. That reminds me of a mining railway, I saw. That was used inside the mine to draw the small carriages with lead ore. When it was converted to electric drive, they used a 3 phase 400V overhead wire system – less than 2 m above ground. I think it was very good for the engine driver, that all mining workers wear plastic helmets. Otherwise he could have easily touched the wires with his head while sitting on the engine to drive it.

    1. We don’t want none of that prius-driving stepped-down wussy electricity! Give us the high voltage transmission lines straight to the garage, all 345 kilovolts. It’ll be fine! I want every outlet to look like a stack of dinner plates because of the HV insulators. Six-foot arcs jumping out to vaporise the pets and small children.

      1. It’s simple really. Our last mile distribution carries 3 phases, but each home only has taps to 2 of them, but in a every-3-home cycle. So you may have phases A+B, next door has B+C, and next to them C+A, before the pattern repeats.

        Due to this, we obtain 3-phase by running a long extension cord through the yard and over the fence to our neighbors to access phase C, while they do the same with your A or B.

        This is better because it encourages a community of sharing and cooperation, along with higher educational standards from the necessity of first hand electrical safety and distribution logistics that are typically reserved in other countries for the elite few that learn “proper” electrical engineering, whatever that means.

        1. Not quite. US last mile MAY be 3 phase, but the typical household only pulls one. Outside of heavily populated areas, you’ll see three phase power split at the distribution level with miles of single phase spidering off through sparsely populated areas. The higher voltage distribution line is then stepped down to 2 legs of 120V (240V comes from the 2 legs being 180 degrees out of phase to each other). A neutral line to the end customer is generated in the windings of the distribution transformer and bonded to the neutral of the main line.

          In contrast, “European” distribution is more akin to US industrial power, where the phases are stepped down in what I understand to be a 3-phase Wye configuration. In this configuration, each line directly measures 240V to neutral.

          A 240V outlet in the US will end up with 4 wires: 120V x2, neutral, and Earthing ground (older houses will have 3: 120 x 2 and a ground). A 240V outlet on the European standard will have 240V, neutral, and Earthing ground.

          1. US household mains split one phase of power into two opposing 120v lines using a center-tapped transformer, where “nuetral” is the center tap that is “grounded” at the transformer and main electrical panel.

            For safety nuetral is also usually “bonded” at the main electrical panel to the water and gas distribution pipes inside of the house (so that if a conductor makes contact it will get back to ground and trip the the breaker instead of being a potential shock hazard).

          2. That’s more accurate, also here in the UK we give each side of the street the same phase which is presumably to reduce the chances of people trying to derive 3-phase from their neighbours. By a stroke of luck though, I have 3-phase running right into my house (although I currently (sic) am connected to only one phase.)
            I have been in a test lab where the 240V outlets in different parts of the lab were on different phases, and there were bloody big notices above the sockets warning you not to connect them together! (As though you would…)

          3. @abjq Your post scares me on multiple levels.
            I was making a joke that, I had hoped, was so silly and far out there just to self-mock our US system.
            Do you mean to say that not only has that situation happened, but happened enough a mitigation was actually put in place to stop it? And that mitigation is only partially effective at stopping people from doing it?!

        2. In the US, that “2/3” configuration is common in apartments and condos in densely populated areas, but not at all common for individual houses.

          BTW, if you actually have 2 phases 120 degrees out of phase, it’s theoretically possible to generate the third using a pair of autotransformers. (Try to figure out how!)

        3. I have only 1 phase in the apartment, which is supposed to be enough as heating and cooking is done with gas. But 3 phases enter the building and apartments with electric cooking or heating get 3 phases. It costs a little more, but not much. I own a small ground level storage room and workspace. When they replaced and upgraded the distribution lines in the building several years ago, I should have asked the electricians to prepare the line for 3 phases. It would have been without extra cost for me and would be fine for some motors.

      2. At least you get to pay more per kwh.

        Plus I never needed to run a 3-phase motor, but it would be nice if I needed to, I guess (especially since I’m a master dumpster diver!). I just wired my shop with 220, the lights are on one side and the table saw on the other, so the lights don’t dim.

        Technically I wired my shop so I could connect my solar panels, as they needed 220 for the inverters, but having both power and lights was a games changer and allowed my shop tool to move out of the basement.

        1. Respectfully you must have an interesting service panel. I have yet to see one where when a 20/240 breaker when installed it doesn’t tap both line conductors. Perhaps your flawed theory is tricking your mind not to notice if dimming occuring. Not that i saying the loads shouldn’t be balance. My shop has multiples of both 120 a 240 (single phase) circuits. I have never have seen the lights dim whenever some starts a arc, I did I would immediately start trouble shooting the electrical, because there is problem somewhere. Good luck on the dumpster diving. Even fractional HP 3 phase motors are cost effective to repair, so not many businesses are going to throw them out

          1. A lot of older 115V motors, such as would be on a table saw, will dim lights on the same circuit at startup, particularly if not run daily and there’s a little bearing sticktion. High current surge and probably dragging the phase outa synch for a couple of seconds. Maybe could use a new startup capacitor, but last decade these all seem to come with the no-extra-charge flammable option, so it makes you think twice whether you’d rather dim the lights or light the place up unexpectedly.

      3. I’m being curious. What is the the reason to by default 3 phase service to residences in Europe? Correct it costs more to run 3 phase to the premises in the USA, why wouldn’t it? No matter what it is anything that’s outside the “norm” always cost more. Most homes, and farm/home shops can can function fine with 240 VAC sibgle phase. The very few that may require 3 phases can use use a phase converter. supply 3 phase to locations that don’t need , unnecessarily raises the cost of providing service to everyone, with those who don’t need 3 phase subsiding the cost of those who need it.

        1. It’s more of a legacy, but it allows to keep the phase loading balanced and more importantly, single phase motors are limited to 2kW here, if you need more, you need 3-phase. Keep in mind that VFDs cheap enough for the average joe have been available for maybe 15 years tops, before that you’d need a rotary converter, which would be: 1) big and heavy 2) expensive to buy 3) expensive to run (losses) 4) pointless…just rewire the machine for single phase if you must.

          And it will come in handy again when people want to charge EVs. A common, 16A single phase plug gets you a measly 3.7kW, whereas a common 3-phase plug with a 3x16A breaker can toss out 19kW, which is more the good enough for charging in a few hours ;-)

        2. Quite a number of apartments use tankless water heaters for hot water. For those to be possible, you need 3-phase power. The one I have has 3 fuses with 32 Amps each. That’s a total of 22kW heating power.

          Upside: You get an endless supply of hot water.

          Downside: If you really use it for long showers, your power bill will be sky high.

          As for the cost of 3-phase power.. All transformers I have seen here are 3-phase and the cable that comes into the house has 4 wires (L1,L2,L3,N), so it’s not that much more effort combined with the american system.

        3. I don’t think its standard. Common in Poland, Germany, and NL (from my all be it limited experience). France I am not sure. UK no. Spain no (again in my limited experience).

          I am in the UK and would personally love it #1. For machinery and #2. For easier electric heating. I am off grid for natural gas so use electric and a wood burner. If all the electric heating (50 amp max) is going full power we have to be careful as to avoid over current the supply (100 amp). Add in an immersion heater (12 ish amp), oven (32 amp breaker but not sure of actual draw off top of head), tumble dryer, kettle, odds and sods and you can see its easy to create quite a draw for sort periods.

    1. My experience tells me that you got anything between 95 and 130V in the outlets, depending on the time of the day/load of the net.
      That’s OK unless you need to transform it up to 240V, so the swing doubles, or if you need to transform it even higher…

      Seriously, the brownouts are massive, and so are the peaks.

      1. My friends UPS tracks the incoming voltage and I was amazed when he showed me how much variances in the voltages happened in 1 day. It swung from 90 to 130 up and down all day only at night was there a consistent voltage near 120! He lived on a farm pretty far from a substation so could have been why he got so low voltage when everyone was running their AC’s on hot Florida days! Now they sold the farm and it was turned into a solar farm, his voltage is steady there now lol except when their inverter/transformers blow which happens quite often due to salt air!

        1. WTF part of florida do you live in with such a bad power system? I am in Tampa with an APC 1500 SmartUPS and I graph the voltage and other stats of the UPS with MRTG. The voltage is pretty rock solid at 120v with +/- 2-3 volts now and then, It does not ever significantly deviate for any length of time. Probably from dips in the power when large current devices like AC, water heater kick on and off.

      1. Britain is also in Europe – although it probably leaves the EU, the islands will not move :-) They had 240V, we had 220V and so it nominally got unified to 230V with some trickery of the tolerances

    2. When I lived in North America (many years ago) the standard voltage was said to be 117V. Did they really make physical changes to the distribution system to get today’s 120V, or is it just a voltage tolerance adjustment like the European harmonized 230V?

  1. Texas has it’s own grid though. Pity Japan with the lowest voltage but split between 50 and 60 Hz. The north was starving for power when Fukushima went offline. 3 rotary converters were able to bridge a tiny amount of power south to north. Basically two grids on one big island.

  2. I’ve visited Australia a couple of times and it’s nice being able brew a cuppa in a minute teapot by boiling water in less than a minute. Also, with double the voltage, you can get away with smaller electrical cords due to less current required on the power tools for instance.

    1. interestingly in the UK, power tools (used professionally on sites) are designed to run on 110v. with a ground-centre-tapped tranformer, so should any “leg” of the 110v cord get exposed, its only 55v to ground through a human.

      home gamers use 240v tools, and light industry like me is 240/480v 3-phase.

      but yes, boiling a kettle in a 110v country is an exercise in frustration, and this applies to mainland europe too tbo despite the 240v their kettles are crap. good reaon to leave the EU.

      1. How powerful are your kettles?
        The average western european kettle is 2000w these days. I know that 15 years ago, most of them were around 1200w.
        But 3000w kettles are easy to find. Doesn’t get much faster than that!

        1. 3kw is normal in the U.K. a friend with solar had to do some work to find a lower power kettle that would fit below his solar production (which made it free to boil due to feedin tariffs).

          But in the U.K. our water is crying out to be made into tea, so it boils much quicker.

          More seriously, we actually do have a hydro reservoir specifically to power all the kettles boiled in the ad breaks on popular TV soaps. It’s refilled by pumping back off-peak, I believe.

          1. I moved from the UK to Switzerland, and had to give up my 3kW fast boil kettle. Sockets here are only 2.5kW (10A at 230V). It’s just not the same. I did think of plumbing the kettle into the high-power feed for the cooker, but sadly it’s not accessible in my apartment.

            I have no idea how Americans manage with 110V. Maybe they just don’t drink tea or something.

          2. Sadly I learned that kettles boiling is only a small part of the TV-led demand spikes – more of it goes into fridges which have had their doors opened, and pumping water uphill to reservoirs to replenish what was used by flushing toilets. Do the national grid a favour and if it’s yellow, let it mellow

          3. Thats because you’ll be hard pressed to find electric kettles in most american homes. Want tea? Throw a cup of water in the microwave and nuke it for 3 or 4 minutes. Done.

          4. My 1500W kettle will boil a cup of water faster than my 1300W microwave.

            I took 2 cups of room temperature water, put 1 in the microwave, 1 in the empty kettle. I timed the microwave to the first big boil bubble (130s), and the kettle until it turned itself off (98s).

            Numbers seem a little off. 1500W * 98s is 147KJ. 1300W*130s is 169KJ. The kettle appears to be more efficient. Also, the kettle turns off after about 10 seconds of a full roiling boil. I really should have zapped the cup for even longer to get to that same point. I’m guessing two major factors play into that efficiency difference: First, not all of the microwaves energy hits the cup of water. Second, the heat capacity of a ceramic mug is higher than that of the thin stainless steel of the kettle. Also, I cannot rule out the possibility that one or both of the power ratings are wrong. The kettle rating came from the power safety sticker on the base, so is likely to be fairly accurate. The microwave rating came from the marketing number on the door so could be rounded up. Both appliances are on the same circuit, and tests were run immediately sequentially. I believe that we can discount voltage differences between the two. I suppose we could repeat the zap using a paper cup to minimize heat lost to the vessel, but since I would use a real mug when drinking tea…

            Further analysis. 8oz of water = ~237g. SHC of water is 4182J/K/Kg. Room temp here is 69F. So to raise 237g of water by 79.5K will take ~78800J. That would be 52.5s for a perfect 1500W kettle, or 60.6s for a perfect 1300W microwave.

            Of course, none of this really matters. The trick is to use the kettle to boil just enough water for the first cup of tea each morning, then to immediately fill and boil it again and keep drinking tea fast enough that it never gets to cool down.

          1. Be careful with that, it’s possible to superheat water in a microwave. That leaves you with a cup of water that isn’t visible boiling, but as soon as you disturb it it flash boils into steam.
            I’ve seen it happen with a cup of coffee left in a microwave for about five minutes. It looked fine until someone added more sugar, whereupon it exploded. Fortunately it only resulted in a small burn to the person dropping the sugar.

      2. I live in a country where “standard” outlets are 120V. I don’t like waiting for water to boil, so I had a 240V outlet pulled to my kitchen and use a 3kW british kettle to boil water.

      3. Because you are doing it wrong.You either use a gas burner, or an espresso machine with the steamer.
        Besides in Italy there were a lot of electric companies and a lot of different voltages, depending on who was delivering the electricity. You had appliance with multitap transformer or external transformer/stabilizers for tv sets http://curiosando708090.altervista.org/oggetti-del-passato-stabilizzatore/ This lead of a nationalization of the power grid and a voltage unification.

        Some residuals of the mess of the ’50 is that you can find either a 240 three-phase distribution, and you have on a single phase both the wires live, or the more common 400 three-phase one. Sometimes in the same city a side of a street has different 3-phase voltages…

  3. “European power companies, on the other hand, pushed the voltage to 240 V in order to improve distribution efficiency”

    Yes and no.

    It has been 220V (since the start in Berlin in 1899) for next to all of Europe – except the UK, which is (has been) a 240V island. And both are based on doubling the US standard which was 110V in 1899 – at the point when the UK finally standardized their systems, after the war, US voltage had creeped to 120V – so 240V came natural.

    Standard in Europe is by now 230V. Since 220V, as well as 240V are within the tolerance, this a slow switch over. Without throwing away all equippment.

    1. Yup.

      And for a long time bringing light bulbs with you when you visited the island (aka “UK”) was a common thing, because those 240V light bulbs may burned ever so slightly dimmer than our 220V ones – but lasted MUCH longer.

      Now we don’t have light bulbs no more. And soon we have no UK no more. Well …

      1. I think that must have been a small minority, which had done this. Think about the price of a litghbulb in comparison to the cost of the electricity wasted by reducing the meager efficiency of the incandescent bulb even more. And it makes the light even more yellowish. I am glad we have 4000K and 6000K LEDs in the meantime.

          1. Bad colors is mostly what you get when you buy the cheapest LED’s.
            Look into CRI = “Color Rendering Index”.
            There are quite a lot of LED’s which produce a decent to very good “white”.

            The blueisch LED’s do have a bit higher efficiency, and are the cheapest, which results in them being popular in lot’s of areas where nice colors are not very important.

          2. What paul said… complaint sounds like one that has been outdated by 15 years or so. First wave of LED lighting, sure, no choice. Now, the fault is that the monkey handed over the metal disks for the wrong thing.

  4. Beg to differ on the “no plans to change it”. My dad was on the international committee for standardization.

    Also, Australia is actually 230V, -5% +10%, like most of the 400v three phase world

    1. Yep, same here in the Netherlands.
      We “switched” from 220Vac to 230Vac some 10 to 20 years ago to unify worldwide voltages.
      In the us the “split phase” 230Vac system seems to be gaining traction too which is another step in unifying mains voltages.

  5. ??? – Many of the adapters I have support 90-240v. I do have ‘fun’ with the outlets differences. That can drive you nuts even with in a country. I accidentally picked up a 120v 25A AC unit instead of a 220v Unit, there are a lot of outlet types when you start to get to higher current.

    1. Depends on where you live.
      Here in the netherlands it’s pretty simple.
      Home appliances all have the same sockets and all household stuff is designed for 230Vac.
      There simply is no 120Vac.
      For higher power (>3kW) there is the 3-phase system, which uses different sockets.

      Some high-powered appliances such as kooking stoves use 2 phases. These are often built with separate heating elements, so if you connect only one phase, then you have half the power, (or it does not work as the transformer for the front panel display + buttons is on theunconnected phase).

      Small SMPS adapters are relatively easy to design with a wide input voltage.

      1. I think that can happen with North American standard stoves, they’re on each side of a 115-0-115 hookup. The main bake and broil elements are across the full 230, but I think the burner elements, light, accessory plug socket etc might be on different 115V legs.

  6. What no mention of Ohm’s law? it’s very simple power losses in a wire are IIR – they go up with the square of the current, double the voltage you halve the current and the power losses go down to 25% – more importantly you can either provide 4 times more power in a circuit with the same wiring, or use 1/4 of the copper in the wiring for the same power (Cu is expensive these days) – it also means pulling stranded wiring through the walls rather than solid core wiring.

  7. Kudos to the writer for clearly and succinctly explaining line, neutral, and ground. Many HaD writers would have said “LNG” and left it at that. Looking at YOU, every other HaD writer!

  8. Strange I am the first to post about this, but I think there is a mistake (petty) in the article.
    Modern electronics manufacturers have for the most post made this a non-issue by designing power supplies that will happily function on either 240 V or 110 V

    “have for most post”?

    Shouldn’t it be: “have for most part”

  9. >> It’s surprising really that Texas didn’t want to go for 360V to show them yooropeens hwat’s hwat.

    Weird fact – Texas is almost a standalone block in the US power distribution system. it has very few interconnects.

    This is mostly a quirk of infrastructure history related to the exact timing of electrification in the west, as opposed to, say, planning for secession part II, but nonetheless, if you wanted to disconnect Texas from the bigger grid and change it’s voltage, you actually could.

    1. Except you couldn’t, because they need the interconnects to sell federally subsidized wind power.

      The issue being that there’s almost a 180 degrees mismatch between supply and demand for wind power in the ERCOT system. They give it away to people for free to have somebody to waste it, in order to collect the subsidies, but at times that’s not enough so they either have to curtail it and pay the owners for not producing electricity, or sell it to other states.

      Reason being that there’s a very predictable wind pattern going on in Texas. The winds follow the transition from day to night with a certain delay. The peak wind power happens late at night when the grid load has already gone down, because the ground finally cools down and that creates a low pressure zone that sweeps across the plains, bringing winds with it. When the sun goes up, the ground warms up again, a high pressure zone develops and the air starts moving up instead of sideways, so the turbines barely turn.

      It’s pretty much like the California duck curve. You get power exactly when you don’t need it.

      1. Re: power when you don’t need it – Sounds ideal for charging electric cars in the night after using it in the daytime, and also for powering accumulator-type air conditioning systems. Cool a biiiiig underground tank of water or other liquid, and use the cold water in the daytime to cool down the building.

  10. Years ago I did a big computer roll out in Europe. I had configured everything in my office in the US, and the computers all had universal power so the only thing different when I got there was plugging in the computer with prog adapters. And all of them fell right into place except the last one. I hit the power button and the status light flashed a couple times and went out. Weird. I tried it again and a little puff of smoke came out of the back of it and that was the end of that computer. It turned out that one had a manual 110/220 switch on it. Oops. It took me a day to find a replacement but on the plus side, nothing but the power supply got cooked.

    I also used to do sound reinforcement. We had a lot of gigs but one was at a large local theater. One show had a lot of lighting effects and we were getting humming and clicks in the audio so the house electrician offered wire in a couple drop boxes on the sides of the stage on another circuit. Somehow he managed to get us 220 instead of 110. I hit the switch on the one of the amp boxes and there was a big pop, some very loud hum and silence. That took out the fuse in the active crossover, 4 amps, and one of the bass drivers. That was a very rushed van trip back to the shop for replacement gear.

    1. We have a lot of older test and measurement equipment that we keep because it’s so unbelievably expensive to replace. It’s pretty common to have a power supply or oscilloscope that “just suddenly stopped working and I don’t know why” and we turn it around and pull out the mains fuse, which is carried in a plastic holder that can be plugged in several different ways, once for each type of voltage input it’s intended to use, and if the engineer who blew out the fuse doesn’t know about this and put it back in with a different orientation, the machine won’t power up. I’m glad more modern equipment just deals with any input voltage. But at least none of them burn out with the wrong configuration: Hewlett Packard and Keithley managed to design that right.

          1. When dropped or left unplugged, the UK plug is designed to always land on it’s back with the prongs up in the air, waiting for someone walking barefoot to step on it. Gotcha!

      1. The UK plug has nicer contacts, but you can’t insert them both ways. Also, they seem to land on their back, pins in the air, waiting for someone to step on them at night. Schuko’s don’t do such evil things.
        Also, the UK doesn’t have an extra small version without ground pin for double isolated low current devices like desk lamps, radios and such.

          1. Those little round pin 5A sockets are still used commonly for lighting circuits where you plug in a desk/table lamp. They’re usually on a dimmer or turned on/off from the same switches on the wall so you don’t want people plugging in random devices.

          2. You can also insert a 2-prong euro plug in a BS1363 socket just fine, just use a teaspoon (or more preferably something not conductive) in the ground socket to open the ‘doors’, then use a little force. Used this method in hotels many times XD

            You do have to be super careful though to hold the socket when you pull it out because the slight angle of the pins and the edge of the metal contacts can pull the socket right out of the wall. It has happened to me also :P

            PS All the above is extremely unsafe. But it works pretty well when in a pinch.

      2. [SnarkOn] And the stupid UK plug is monumentally inferior to the IEC 60309 “Blue P+N+E, 6h” one[1]. [SnarkOff]

        Srsly though, this debate over which plug is better depends on a lot of factors and you Brits wouldn’t need hurtful plugs with wasteful fuses inside of them were it not for those wired wire loops with two circuit breakers allowing 25A in total (I think).
        And AFAR some of your (older) appliances relay on the correct wiring of N and P for the safety of the user which makes the appliance inherently less safe (thanks to your plugs), don’t they?

        My personal favorite plug is the “TYPE L” [2] if the sockets were recessed like e.g. “Type J”.

        [1] https://en.wikipedia.org/wiki/IEC_60309#Blue_P+N+E,_6h
        [2] https://www.worldstandards.eu/electricity/plugs-and-sockets/l/

        1. The rings only have one breaker and yes, they are stupid, a lot of the regulations to do with house wiring are.

          Jobs for paper pushers for the most part. Hopefully that will change once we eventually do leave the EU.

          1. I’m not from the UK, but I seem to remember those ring circuits were designed during WW2 to save copper.
            That way you could have a single large current circuit and the fuse in the plug of appropriate size for the appliance wiring.

      3. The UK plug has one really nasty flaw though: The big flat back makes it almost always fall down with the prongs pointing upwards. When the girlfriend leaves her hairdryer or GHD lying around this can lead to some really nasty surprises when trying to make your way to the bathroom in the dark. They’re too big to pierce a foot when walking slowly but they can certainly cause a lot of pain :D

        1. That’s a feature, the UK was jealous of the Danish area denial weapon known as “lego” and developed a similarly purposed but more effective ubiquitous object to be dropped in front of enemy troops in event of invasion.

    1. The hexagonal plugs are a compromise to fit into German, French, Swiss, Italian, and Danish sockets. They don’t have a PE contact and are specified for low currents only. Sockets of that type are used in Germany usually to fit several sockets into little space. Sometime they are also used to prevent people from plugging in high current devices.

      When my parents moved to Switzerland they learned the hard way that most Swiss wall sockets are 10A only.
      They had only two sockets capable of more than that and those were in the basement, reserved for the washing machine and the dryer.

    2. I’m from Germany and knowing some of the other plugs I find that Schuko is the best one because it’s robust. On the other hand, I really like the French sockets with the ground pin because it allows, at least in theory, to lock plugs against rotation so that phase and neutral is always in the same place (although there is no standard that defines on which side is phase and one which neutral, AFAIK).

      …and comparing electrical installments of homes in Germany and the USA… it’s like a Porsche vs. a Ford Pinto 😀

      1. Yes the big flaw of the Schuko is its reversibility. There’s almost no point in using blue/brown wires because you can never know for sure.

        I like that about the French ones too but I didn’t know the phase and neutral weren’t specified? That seems like a huge oversight.

        1. Location of the phase and neutral wires are purposely not defined to prevent manufacturers from relying on polarisation.

          Even for the largest household appliances with plugs, dealing with unpolarised connections requires just a few cents worth of components. So having unpolarised plugs doesn’t limit the devices that can be connected.

          However, it does limit the number of accidents significantly, given that in polarised regions, manufacturers tend to only disconnect the live wire. A common example is a toaster, which in the USA or UK may only disconnect the live wire to turn off the heating element. Touching the inside with a knife (like nobody should but all idiots do) to get the burned parts out, will electrocute you if your socket has the polarity reversed. Even worse are some older appliances that assume neutral equals earth and may even tie them together.

          I agree that color coding in appliance cables may well give someone a false sense of security, though one would expect anyone working with electronics to realise this. Then again, I would expect people to know not to put their knife inside a toaster.

          We (most parts of Europe) do, however, use polarisation for fixed installations (including light switches, which do disconnect just one conductor). So color coding is important up to the wall socket.

  11. when I lived in the usa I found anyone doing even home hobby work with power tools had to put on a higher voltage system, as 110v is just useless for a lot of tools..

    And not all power supplies are made for 240v, I reckon a lot are made for 220v – as they can’t handle the plus and minus on the 240v ie I regularly have 254v at my power point and that tends to wear out cheap crappy power supplies relatively quickly..

    1. Trying to learn to stick weld with a 110V arc welder in the 1980’s was a lousy experience. It’s just not enough power: a learner continuously touches the electrode for a moment too long, freezes it, and flips the breaker. I’ve wired in 220 in multiple places in my shop, and it’s such an improvement.

  12. Japan is a special case. After WW2 the US and UK split the job of rural electrification of the islands. They compromised on 110 volts but the Brits insisted on building out their half as 50 Hz while the Americans went with 60 Hz. So much purely electro-mechanical stuff sold in Japan, especially clocks, has a 50/60 switch.

    1. The 50Hz/60Hz split in Japan has a much longer history that that. It dates back to the very first generating stations built in the later 19th century sourced from Europe (AEG in Germany) for Tokyo and the United States for Osaka.

      After WW2 the UK had practically no dealings in Japan which is why most places have the US standard of power distribution with overhead lines on poles in the street.

    1. It was happening as early as the 90s I think, remember one old betamax I was trying to run at one house just seemed to struggle to get the tape up to speed and flutter the display, then turn off, whereas it ran fine at a buddies in the next town over on a different part of the grid. Had big old linear power supply specified for 240V, and meter was saying 232 at the one place, and 245ish IIRC at the other… I know some tolerance should have been built in, but it also had caps drying out for a decade, and when new I think there was no inkling of such happening.

  13. > The UK plug has nicer contacts, but you can’t insert them both ways. Also, they seem to land on their back, pins in the air, waiting for someone to step on them at night.

    Australian ones can do that too if you get one with the cable entry on the side instead of directly out the back. Often such beasts are found on fridges and freezers as the fridge/freezer pressing on the plug does no damage.

    1. Yes – the goals of “Progressive” Marxism are: 1. Collapse the System. 2. Rebuild, making the “Ideal” society. Step-1 is easy. Unfortunately as history repeatedly shows us, the Progressives never make it to Step-2.

  14. So with 220/240 VAC split phase in most residential, it’s fun to see the highrise residential/condos where the building gets three phase and their 220/240 VAC is only 208 VAC. If they or their trade doesn’t know to buy the correct voltage appliance, they end up wonder why it underperforms or doesn’t work.

    If you don’t blance your residential loads between the splits, then you end up paying more for the use of your 110 VAC devices. If it’s a 220 VAC device, it’s a balanced load from the start.

  15. Tidbits….

    50 Hz requires marginally more steel in the core of every transformer than 60 Hz.

    As many point out, for NA, it is 120/240V or 120/208V. There is no 110V or 220V, unless you are measuring it and are experiencing a brownout.

    Niagara Falls had a lot of 25 Hz 100 years ago. Ontario had to convert to 60 Hz starting in 1949. It took 10 years and hundreds of $M. 25 Hz power was finally decommissioned about 10 years ago. Look up Rankine Generating Station which should be turned into a museum soon.

    Some computing facilities in NA operate 230/400V as the 230V is L-N and most every server power supply will accept that voltage happily. So the European voltage is making inroads to certain North American applications, where it can.

    To bad 480V gets into Canadian buildings where a US electrical engineering firm is involved. Canadian 600V distribution is more efficient, and for calculations sake, for a balanced load of say 100A, you have approximately 100 kW.

    Chinese hotels have solved the guest converter issue by using a universal outlet. It can accommodate most plugs from all over the world. Of course, that would never be acceptable where standards bodies and lawyers rule… but the Chinese are a bit more practical and demand personal responsibility for mischief or misuse.

  16. Major error in this article – The majority of the world, INCLUDING the united states receives 220V-240V single phase. I have never seen a house in the USA which does not receive 220-240V single phase. We simply have chosen to break out half the phase to outlets. The reason for this dates back to the introduction of electric lighting, as the USA was ahead of the rest of the world in this area… The half-phase standard was retained despite changes in lighting technology over the years. 120V countries have the benefit of requiring only 3 wires for their 120V outlets as opposed to 4 wires for many 240V outlets (especially by today’s code) saving in wiring costs and reducing complexity of the outlets, but with the disadvantage of requiring polarized plugs and more careful wiring for the outlets… One can make many arguments for one standard vs. the other but the bottom line is that since the advent of switching power converters, it really hasn’t mattered.

    1. My understanding is most of europe receives 3 phases. At least that’s the case where I live. Usually those 3 phases are used as such for waterboilers, ovens, powertools, saunas and so on, and the rooms (lights & sockets) are actually wired with one phase, so that different parts of the house use different phase. It’s handy when a fuse blows as the whose house isn’t left dark.

      1. I don’t believe that any house is left in the dark when a fuse blows, USA domestic electrical circuits for residences are limited to 20A and in most cases are 15A, when you trip a breaker it is only one circuit. If you trip your main breaker, which is almost always 200A for new construction in USA, then something is seriously wrong and it’s a good thing that everything is dark!

    2. Except for significant distribution losses or requiring much more material.

      US homes tend to have far more circuits which additionally require thicker wires than 230V systems. Most European wall outlets will supply 16A at 230V. That’s 3680W. This can be delivered on 1.5mm diameter conductors, though 2.5mm are generally used.

      To deliver 3680W at 120V, while keeping distribution losses equal, you would need a 5.1mm diameter wire. That’s more than 4x the amount of copper.

      1. I am not aware of any use cases where the typical ~1500W limit (15A*120V*0.8 due to NEC 80% continuous rating) on common USA house circuits is a problem – Kitchens and the like generally get 20A circuits giving you 2000W continuous all day long which will cover larger motored devices like those monstrous blenders that people use. I believe that the lower voltage may be one reason that we tend to have more outlets in houses in the USA than in EU, but then again that could be due to the age of the construction since it seems that half the buildings I visit in EU seem to have been built ages ago and wiring is often in visible raceways. Not sure. I like having more outlets for more convenience of where one can plug stuff in, wandering electrical cords bother me.

        You can do 30A circuits with 10AWG wire but NEC disallows more than 20A for 120V residential outlet circuits so it’s a moot point in USA. I don’t know why you would do it anyway when you can just run a 240V outlet. I’ve installed 3 in my place, they are not the same plug as the EU (we have several allowable NEMA options in USA depending on application and whether neutral is required) and they aren’t any harder nor more expensive to wire than a 120V outlet. The only inconvenient thing is that they require double gang box but that would be the case with EU socket type too so it doesn’t seem to matter.

  17. The US uses 110-120V because the original Edison DC system was 110V DC and by using a similar voltage for AC the same bulbs could be used along with devices with universal motors could be used on the new Westinghouse Tesla AC electric system.

    By the time Europe started electrifying the war of the currents was mostly over and the new metal filament bulbs could be made to make use of the higher voltage.

  18. Having lived in both 110v and 220v countries. I now really appreciate the 110v standard. First of all, most devices do not need large current. Things like light bulbs, even back in the 100W days, just require a current of 1A on 110V. Most modern devices ended up stepping down the voltage anyway. But the 110V outlet has a clear advantage. Where 220V is used, their outlet usually has just 1 socket and their socket is HUGE. Where as the 110V outlet usually has 2 sockets that I can plug in 2 devices easily. 220V power strip is also huge, due to safety reasons. I am glad that US chosen the 110V standard.

    1. Weird experience of yours!
      I live in a 230V@50Hz country and I’m currently seeing a wall socket sized 10x5cm [ yeah, also metric system here ] with 2 appliances plugged comfortably. Also have laying around a strip with 5 sockets sized 30x5x2,5cm.
      (No buzzing or smoke coming out either)

      1. Your sockets are much more bulky, even the device end, I always bring an EU plug for my laptop on travel there and the end of that thing is annoyingly large. Your dimensions are way off, or you are talking about the two prong w/o ground which is not equivalent to the USA socket – All appliances are required to use ground in both EU and USA and all USA wall sockets have ground. Recheck your data, it is not correct for EU standard.

        1. Don’t know about EU standards since I’m not in the EU.
          The sockets have Line, Neutral and Ground [ here is also required to have Ground or the appliance can’t be commercialized unless it has double isolation ] wired with 1,5mm^2 or 2mm^2 if the load is large. So 3 prongs.
          It worth to mention that we are not a 3kW-kettle-centered nation.
          So, data rechecked ’round here ;).

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.