Why does the world harbor so many different voltages, plugs, and sockets?
spectrum.ieee.org
spectrum.ieee.org
It's interesting to look a little beyond that. Most of the places that offer 230 V at their outlets seem to be distributing power in the neighborhoods using a 3 phase 230 V system. Individual houses are wired to one phase of that.
In the US, distribution throughout a neighborhood is typically 15 kV. There is a 240 V center tapped step down transformer for each house. The normal outlets in the house are wired across half the transformer, giving 120 V. Ovens, water heaters, dryers, EV chargers, air conditioners, etc get wired across the full transformer giving 240 V.
There was an interesting comparison of the two approaches in this Quora answer that turned up in my Quora digest mailing two days ago [1]. (Not sure if the link will work without a Quora account).
The result is that the high voltage appliances need to support both 240V and 208V. Most appliances just design for 240V and test to ensure they don't break at 208V, and just give reduced power at 208V. Which is often fine, but a 208V stovetop is a pretty miserable experience.
In many countries houses get wired to all three phases and the phases get split up afterwards, sometimes with a few 3-phase plugs available for high-power applications.
Or all 3. I thought this was most common. 3x20A (or 16 or 25) 240V is the standard for detached houses in parts of Northern Europe at least.
Maybe in rural areas, but in (sub)urban areas, you'll have a... ?node? step-down transformer serving many homes.
> The normal outlets in the house are wired across half the transformer, giving 120 V
Would add that homes usually balance this, so half of 120V circuits will be wired to one phase, and half to the other. So sometimes you get power failures where half the house loses power. Also means installing power-line networking may only work (well) when they're on the same half of circuits of the house, unless you add a capacitor between the two sides to bridge the gap for high frequencies. Or turn on a 240V appliance to bridge the two sides together.
Why not just give the 120 V up and go full 240 V in every outlet?
No one feels it's worth the effort.
You'd need two sets of plugs in every home and redesign a whole bunch of appliances and sell both types during the change over period, which could last decades.
Type C (the "europlug") is a compatibility low-amperage plug (2.5A @ 250V) for shavers and small lamps and USB power adapters and such. It was designed to be compatible with the high-power Type C, E, F, and K popular in mainland europe, but providing a cheaper plug, and allowing for dedicated low-amperage circuits (e.g. shaver sockets which would be safer in bathrooms).
Type H (and N, which is brazilian) were then designed to be compatible with the Europlug in turn.
> Then, main room air conditioners use Type M - but at least that's standardized...except for when it isn't.
Possibly rather than Type M (which is a 15A plug) it's the 30A plug from the same over-arching BS546 standard? Or a similar-looking 3-phase plug? That's what I'd expect for high-power applications like AC. I assume the standard Type H is 15 or 16A single-phase aka the usual mains.
The M used in Israel might be different than the one pictured as it is used exclusively for 3 phase lines (so an AC that doesn't need 3 phase can then have a regular plug)
One metric: easy of use in the dark/based on feel alone.
Reliability: Fit should be good. You should be easily able to plug a heavy transformer on a downward facing socket without it falling out by gravity alone.
Lastly, compactness. The standard should be compact so fittings can be good looking and not use too much space.
The UK grounded connector fails the last criteria. The US flat-face fails the first two.
(The requirement to have a fuse in every plug is a necessity for UK ring mains, but makes the things even bigger than they otherwise would be.)
Wonder if anyone ever arrived in the UK feeling the same way..
> (The requirement to have a fuse in every plug is a necessity for UK ring mains, but makes the things even bigger than they otherwise would be.)
Yes. It’s much too bulky to be acceptable anywhere where people aren’t used to that size (nor would anyone accept fuses in the plugs I think. Unsure about switches at sockets).
(Whether this is legally required in the US presumably depends on local electrical code.)
Swiss Plug:
https://www.worldstandards.eu/electricity/plugs-and-sockets/...
https://en.m.wikipedia.org/wiki/SN_441011
Compact 3 socket version: https://www.bauhaus.ch/product-images/52/95/22025295/1009627...
Multiphase: https://en.m.wikipedia.org/wiki/SN_441011#/media/File:SEV_10...
Chart of all current/phase versions: http://www.toplight.ch/info/ch_plugs.pdf
And non-recessed sockets, which the Swiss socket allows while Schuko doesn't, make me uneasy.
[1] https://en.m.wikipedia.org/wiki/SN_441011#Structure_of_the_S...
Indeed much more compact than type E or F.
French sockets (https://www.worldstandards.eu/electricity/plugs-and-sockets/...) have a male pin that forces your plug one way only. This is terrible because most (if not all) of such plugs are bent and sometimes do not physically fit.
German ones (https://www.worldstandards.eu/electricity/plugs-and-sockets/...) do not have a prong and ple plugs can be rotated 180°
This is extremely uncommon and basically only happens with power strips which both are the "wrong" way around and can't be reversed.
(and since pretty much every plug nowadays is an E/F hybrid, you can easily get a type F power strip for the rare case where it's needed).
Beside the case of the strip you mention, there is also the more mundane physical space above the ground, or other physical limitations.
In my case it is not extremely uncommon since I thought to myself a few times recently "oh no, again this £¨%¨¨£ pin".
IEC 60906-1 was developed to be the standardised global standard, with the intention of rolling it out across the EU first. However that didn't happen and so far South Africa is the only country that has chosen to adopt it.
Brazil and Switzerland have closely-related local forms of IEC 60906-1, but neither is fully compatible.
For example the absurdly large UK plugs with integral fuses date to first (or was it postwar? I forget) surge of electrification which,for expediency’s sake was often point-to-point (like “party line” phones) so local devices needed protection. Nobody else went this route (well, excepting some dodgy informal systems I’ve seen in India and southern Africa) so could get away with smaller, less expensive plugs.
(And as for terminology, why do we plug the plug into the plug in Australia?)
Like, it is possible, if one finger in a hand is touching the live prong, and another finger on the other hand is touching the neutral/ground prong, you'd pass current across your chest.
Or if you are touching something that is grounded, like a pipe/sink...
But actually dying this way is rather unlikely.
With respect to UK plugs, it's also common for them to have the live pins only half exposed, with the rest being insulator, to avoid the possibility of touching live pins while the plug is partially inserted.
On the mainland the sockets tend to be recessed to work around the risk, but the "europlugs" (which are not grounded) almost all have this property as they can't really be "sealed in".
Still harder to do than it looks, and to your point, very difficult to actually die from. Not impossible, but very unlikely.
The modern US one (NEC) is probably the best trade off of size and safety (see my parallel comment on its physical design). Though I do think there is still too much use of two-prong plugs, despite the near ubiquity of grounded sockets these days.
You can’t see this structure in the standard diagrams such as the ones in the article but you can tell it for yourself by inspection.
Although it is extremely solidly built, it's mostly built for a different context: the UK mostly uses ring circuits (similar to a ring network) rather than the radial topology used pretty much everywhere else. This means there can't really be "small" fuses at the fusebox, you can't put a 16A fuse for the entire ring because that'd be the load for all the devices in the house.
As a result you need smaller fuses at the plug level. An advantage of that is that your fuses can then be sized specifically for the appliance cable, and thus you can safely use much smaller cable e.g. let's say that you want to design a 2.5A extension cable, you can put a 2.5A fuse in it and be safe. In a radial context where plugs are unfused, somebody could plug a 10A appliance on the 2.5A cable and melt the cable, the fuse only protects the "wall" circuit and won't blow until >16A (generally).
In fact this has been an issue in the US in the last few years: because of the low voltage, 20A circuits have become more common, but extension cords are still usually 16A. If you plug a 16A cord to a 20A circuit and draw 20A from it, the fuse will be perfectly happy (everything's fine as far as it's concerned) but the cord can catch on fire.
Anyway since they needed larger plugs for the fuse, I expect the UK standards body reinforced the plug while at it.
Technology Connections recently made a video about this.
34 years in the US. I have never been electrocuted when plugging/unplugging anything. I dont know anyone that has been.
Wtf are you playing at? Everywhere across the planet has to adopt things that make you comfortable because you apparently dont know how to not touch the metal bits when unplugging something? Wait no, you're the one they write, "Dont eat package" for, aren't you?
It was during WWII, and it was less expediency and more efficiency and saving on copper. Ring circuit can deliver more power to more surface with less copper.
The UK used to use standard radial topologies before WWII, this is also allowed by modern building code, and very high power devices (>3kW) generally have their own "radial" circuit.
Why Argentina used the same plug as Australia I have no idea, and it's not fully documented as far as know.
So when I had to make an emergency trip, I assumed my newish Dell with USB-C charging would be the same. And that assumption was false. Unless you're charging with 20V USB-C (not common outside of laptop chargers), it won't draw anything at all.
Isn't one particular plug prevalent in all modern installations or at least prevalent in particular geographical areas?
The size looks very similar to European Schuko sockets, and if you jam it in, then it will just about fit (without an earth). You can get adapters all over the place, which is the way you are supposed to do it, but for older sockets they don't really hold very well so often come loose. Apparently there are sockets that will take all three, Schuko, 10A and 16A but I never saw those while living there.
It's not just to trick tourists though... When you buy electrical products, sometimes they come with an Italian plug, sometimes they come with a Schuko plug.
Meaning that nowadays three ways sockets ( Schucko/10 A/16 A) are common enough, but a Schuko (or a three way one) will take two "modules" whilst both the 10 A and the 16 A are narrower and take a single "module". (typically electric boxes in the wall are either a model 503 - three modules - or a 504 - four modules, but these latter oness can only be found in more recent houses), so until the use of 504's became more common, historicallty Schuko's were rare, as it was not possible to have in the same box a bipolar switch+fuse+Schuko (while it was possible to have bipolar switch+fuse+16A) which is/was the proper setup for high power sockets and with a single socket installed, it resulted in looking asymmetrical, see:
https://www.elettronew.com/blog/2017/05/11/presa-elettrica-t...
JFYI, recently came out a new kind of socket (not yet very common) that allows in two modules to insert either a Schuko or two 10 A (or 2x16 A or 1x10A and 1x16A):
https://www.archiproducts.com/newsletter/dossier/193843
The 10A one is actually compatible with the class 2 (earthless) Europlugs:
https://en.wikipedia.org/wiki/Europlug
Schuko's have larger pins, and it is not a good idea to jam them in a normal Italian 10A plug as the plastic cover of the plug might crack.
Fixed that for you.