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Why does the world harbor so many different voltages, plugs, and sockets?

spectrum.ieee.org

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Re: Why does the world harbor so many different voltages, plugs, and sockets?

#61

Post by alkonaut »

pja wrote: post #60
alkonaut wrote: post #56

Earlier quoted context omitted.

> UK plugs are the best plugs. 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).

Why would people not accept fuses in plugs? (Apart from the size issue & in reality you could probably fit a fuse into a modern US plug without making it much bigger than it is now.)

Because it adds another point of failure for a safety improvement thats extremely marginal.

Re: Why does the world harbor so many different voltages, plugs, and sockets?

#62

Post by p1mrx »

nwallin wrote: post #37
tzs wrote: post #20

The article seems to be mostly about voltages and plugs/sockets that the consumer will see at the outlets throughout their home. 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 typical…

It's also common in the US for neighborhoods to have 240V 3 phase, and for a neighborhood to have a common neutral. Each house gets the neutral and 2 of the hots. Hot to neutral gives 120V, hot to hot gives 208V. (240*sin(120 degrees)) 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 reduc…

You could run a heating element at full power on 208V by adding a center tap connected to neutral. For something fancy like an EV charger, you would probably need dual 120V AC/DC converters, which isn't worth the effort, given that constant-current loads run at 86% power (208/240), compared to resistive loads at 75% power (208/240 squared).

Re: Why does the world harbor so many different voltages, plugs, and sockets?

#63

Post by masklinn »

ginko wrote: post #17
varispeed wrote: post #13

Earlier quoted context omitted.

I am always getting anxious that I get electrocuted when I disconnect US plug. I wish the whole world adopted UK plugs and sockets for safety.

UK plugs seem way overengineered. European schuko plugs have all the same advantages without weighing a ton.

> UK plugs seem way overengineered.

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.

Re: Why does the world harbor so many different voltages, plugs, and sockets?

#64

Post by masklinn »

gumby wrote: post #57
edrxty wrote: post #30

Earlier quoted context omitted.

Further, the UK has twice the voltage which means twice the current will pass through you. The US 120v system is pretty safe in general. If you do something really dumb it'll kill you but 120v isn't really that concerning compared to 230-240. The cutoff for dangerous voltages is usually considered to be around 60v.

The bulky UK plugs also have a longer ground, as do compliant plugs in Germany and Italy (at least)

Yes, pretty much all european plugs are designed such that you can not connect the live before the ground is connected. In UK plugs, the connection of the neutral will also open the safety doors and allow connecting the live at all (that is not the case for mainland plugs, at least not the 7/7 ones).

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".

Re: Why does the world harbor so many different voltages, plugs, and sockets?

#65

Post by masklinn »

BrandoElFollito wrote: post #28
evolve2k wrote: post #12

I know it’s likely highly subjective and prone to local bias, but I feel a next step would be to do user testing of alternatives and derive a best form factor plug. What’s the best plug we could all be aspiring to. Some are clearly more usable than others. One metric: easy of use in the dark/based on feel alone.

another metric: independence of the direction for ground. 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 rot…

> This is terrible because […] plugs […] sometimes do not physically fit.

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).

Re: Why does the world harbor so many different voltages, plugs, and sockets?

#66

Post by ficklepickle »

masklinn wrote: post #63
ginko wrote: post #17

Earlier quoted context omitted.

UK plugs seem way overengineered. European schuko plugs have all the same advantages without weighing a ton.

> UK plugs seem way overengineered. 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…

> 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.

Technology Connections recently made a video about this.

https://www.youtube.com/watch?v=K_q-xnYRugQ

Re: Why does the world harbor so many different voltages, plugs, and sockets?

#67

Post by BrandoElFollito »

masklinn wrote: post #65
BrandoElFollito wrote: post #28

Earlier quoted context omitted.

another metric: independence of the direction for ground. 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 rot…

> This is terrible because […] plugs […] sometimes do not physically fit. 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).

"Extremely uncommon" would need to be quantified.

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".

Re: Why does the world harbor so many different voltages, plugs, and sockets?

#68

Post by jsnell »

sschueller wrote: post #41
evolve2k wrote: post #12

I know it’s likely highly subjective and prone to local bias, but I feel a next step would be to do user testing of alternatives and derive a best form factor plug. What’s the best plug we could all be aspiring to. Some are clearly more usable than others. One metric: easy of use in the dark/based on feel alone.

I definitely have a local bias but I believe this one has the best of all criteria. From compact to safety (improved 2007 version) and robustness as well as being polarized. 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…

I don't like the Swiss plug. The 3x socket has a problem where a bulky charger will block all three sockets. I'd almost always rather have two sockets with some space between them.

And non-recessed sockets, which the Swiss socket allows while Schuko doesn't, make me uneasy.

Re: Why does the world harbor so many different voltages, plugs, and sockets?

#70

Post by frosted-flakes »

pja wrote: post #60
alkonaut wrote: post #56

Earlier quoted context omitted.

> UK plugs are the best plugs. 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).

Why would people not accept fuses in plugs? (Apart from the size issue & in reality you could probably fit a fuse into a modern US plug without making it much bigger than it is now.)

String lights often have fuses in the US.
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