Digital Museum of Plugs and Sockets
plugsocketmuseum.nl
plugsocketmuseum.nl
This means: we have numerous converters on our devices. We are paying the price for them and not all of them are specially efficient or durable. It is time to standardize a multi voltage DC connector so I can connect all my electronic devices directly to mains without the need of any converter. My LED lamps would be significantly less expensive, more durable and (maybe) more efficient if they didn't have to house a small converter inside the fake bulb. Sometimes you have to replace the "power board" of your TV... it shouldn't even exist if we had a standard for DC mains.
It is time to pressure power distributors to provide huge powerful converters just like they do with transformers, This way we could have quality cheap DC inside our homes without any of these numerous redundant dubious quality converters we need today.
Even within a system the size of a desktop PC, the architecture that has been determined to maximize efficiency and cost savings is an AC-to-12VDC power supply box, feeding additional DC-DC converters that produce the necessary logic supply voltages (~1.2V) as physically close to the actual load as possible.
Actually, no. That power supply box contains an AC-to-DC rectifier, followed by a DC-to-DC power convertor: high-frequency convertors are much more efficient than 50Hz transformers and can be built with much smaller components than a toroidal transformer. Yes, you don't want 5V power lines in your walls, but 150V DC would still be more efficient for most devices than 120V AC.
The reason (other than inertia) why we probably won't do that is because of polarity: AC plugs can be inserted either way; DC plugs might destroy the equipment if inserted the wrong way, and most existing plugs allow both orientations. Not sure many people would like to "re-learn" how to insert a power plug.
But, truth be told, I have been thinking about getting myself certified as an electrical engineer so I can install DC voltage lines in my home: I already have DC solar panels (48V), and DC line batteries. It's awfully wasteful to have AC convertors on them all, just because that's the standard we've settled on.
I will concede there may be advantages to centralizing power factor correction. But on the flip side, components like circuit breakers, connectors, and switches for high voltage DC face arc quench challenges that their AC equivalents basically don't at domestic line voltages and currents due to the zero crossing.
In-home batteries are a case where the benefits of DC wiring may outweigh the drawbacks though. That is also the basic situation in those datacenters I mentioned, where power to the racks all comes from a UPS system.
Arcing can become a hazard with large-scale DC power distribution. Old American wall switches often had ratings for both AC and DC service, and the DC current rating was much lower due to arcing. An AC arc self-extinguishes 60 (or 50) times a second, but DC doesn't offer that luxury.
Even 48V can pack a wallop; I've read accounts of wrenches being vaporized when dropped onto bus bars in telco installations.
FYI in most countries low voltage DC wiring is not regulated in the same way AC is.
And modern AC plugs are usually three prong or bigger prong anyway.
Bonus: Three phase transmits more power per "mass of copper" than single phase.
Extra bonus: You will never have the stupid starting capacitor fail on any of your larger domestic motors!
We actually have that connector already: it's the USB-C connector, together with the USB-PD protocol. And with its Programmable Power Supply mode, an arbitrary voltage can be requested.
> It is time to pressure power distributors to provide huge powerful converters just like they do with transformers, This way we could have quality cheap DC inside our homes without any of these numerous redundant dubious quality converters we need today.
You'd still need one per device, though. At the voltages and currents used by most electronic devices, the voltage drop between separate wall sockets would be enough to have one or more of them be outside the correct voltage range (to start with, you'd need a sense wire to each socket so that the power source knows how much to increase the source voltage to compensate for the power drop in the wiring; from which socket would the sense wire come if a single DC/DC converter is supplying more than one?). Not to mention that it would either waste a lot of power as heat (within your walls), or require thick (and more expensive) cables. And that's before considering that what some devices really want is constant current, not constant voltage (IIRC, LED lamps are one example of that).
It makes much more sense to distribute a higher voltage, and convert it to a lower voltage next to the device itself. It's more efficient, allows for thinner cabling, and since you're already converting voltages, you can use AC which has its own advantages.
Not everything I own needs to be Neutrik Powercon... IEC works well for plenty of things, as do the locking IEC connectors. And sometimes you really need to run a 50A3φ extension cord-- which has quite different requirements than the NEMA 5-15 connectors which are common in the place I live. There are several options for that kind of power; portable 3phase distros are not cheap, but they are much better than, say, running the sound and lights for stage off a bunch of daisy chained power strips :D
There are so many different usage conditions for power that wishing for fewer options triggers my Chesterton's Fence warning light.
So if you’re designing an appliance that has to work with these two-prong outlets, especially if it has a metal housing, you want to know which wire is the “shock your customer” one and which is the “probably don’t shock the customer” one.
Nowadays a lot of devices are made of plastic and / or are DC powered so it doesn’t matter as much.
Everyone cares about polarity - when you have a 3 prong plug, then the ground forces the orientation of hot vs neutral, and the two prongs are the same size.
EU/German/Shuko and Italian plugs are entirely reversible and grounded, that’s what the OP probably was referring to. There’s no way to force an orientation (and thus a “polarity”)
What is it about weak eye sight that prevents someone from turning their plugs over when they find it doesn't fit the first time? Are people with weak eyesight also all THAT short of time as well?
Far easier with polarized NEMA plugs than, say, USB-A.
> I never understood why US uses a wider pin on two prong plugs
Because single-pole switches are cheaper, and ensuring the outer contact on an Edison light bulb screw fixture is neutral and NOT energized is an important safety feature.
So, there was this cottage industry of huge transformers so that these folks could run their US 110v/60Hz appliances on (mostly) 220V/50Hz mains. Things like microwave ovens, blenders, toasters, vacuum cleaners and so on. They were typically oversized and when you turned them on there was an audible hum and dimming of all the nearby lights for both you and your apartment neighbors. They were also often fairly sketchy steel or aluminum boxes without manufacturing labels. I suspect there were probably some dangerous ones.
https://en.wikipedia.org/wiki/NEMA_connector#/media/File:NEM...
and this isn't a theoretical thing, in our lab we routinely use about 10 different plugs for 120 and 240
Then you have historical plugs that don't entirely go away like NEMA-1.
Using IEC 60320 sockets (like for computers and kettles) would be great ( https://en.wikipedia.org/wiki/IEC_60320 ). Failing that, my second choice would be the Australian socket (also used in China) ( https://en.wikipedia.org/wiki/AS/NZS_3112 ).
I wouldn't prefer continental European sockets because while the hot and neutral pins are somewhat standardized, the ground pin and overall shape are wildly different per country (e.g. https://www.plugsocketmuseum.nl/EuropePlugsSockets.html ). I also wouldn't prefer the British socket because it's too big. North American plugs have safety problems due to easily accessible live pins.
So I think you would need to design a new system with at least two different kinds of outlets, and three different kinds of plugs: one for 120V only, one for 240V only, and one for "universal" devices (like switched-mode power supplies) that can be plugged into either.
And of course, once you replace all the outlets with the new standards, everybody would need to get the appropriate adapters for their old devices.
The other option would just be to require all appliances to be dual voltage. This would add several dollars to many devices but they cost would go down over time.
It's academic anyway, a switchover isn't happening any time soon. The only way I can see it happening is if we switch to a system similar to EV charging where all connections are negotiated. Nothing is hot until required and anything operating over current can be immediately identified and disabled. Appliances could even limit their consumption to a lower setting if insufficient capacity was available on their circuit. Such a change could occur due to future regulation and hopefully at a time where the cost of the technology has gone down significantly.
If I were designing a global plug it would not be based on that. I like the layout of Switzerland, but it needs to be smaller - there's no need for that much space around the plug.
Something the size of a US plug, with the Switzerland layout, and shielded prongs instead of a recessed outlet.
That’s the UK plug, Shuko doesn’t have a fuse
I still prefer the Italian plug design due to compact size tho
The Shuko plugs are also ok, easier to insert without looking, but very bulky. It’s in theory nice that they have “bent” (i.e. the cable protrudes at a 90 deg angle) and “straight” plugs, but in practice in most cases you can’t choose which plug to use where.
thats the british one.
> Something the size of a US plug, with the Switzerland layout, and shielded prongs instead of a recessed outlet.
Sounds like the europlug, which is compatible with shuko outlets. Also, IMO a recessed outlet is superior, because it provides some additional support, both against slipping out and breaking off.
I would use flat pins (blades) because they are cheaper to manufacture, and make better electrical contact.
Also the Europlug is too large, my ideal plug would be smaller.
> IMO a recessed outlet is superior, because it provides some additional support
It does that, yes, but it's not necessary for it to do that - it's an unneeded complication. And if that was your goal, just have one blade perpendicular to the other, then it can't slip out (it can only go straight back, it can't tip downward or sideways).
Extra resistance to breaking off is simply not needed, it's not a problem that occurs in the real world.