The reason plugs in the UK are so big is that each one must be individually fused. And the reason for that is something called a "ring circuit".
In a ring circuit you have, say, a 40 amp fuse at the mains/box. From this you send out two wires, each rated only for 20 amps, going in a circle around the house. You can now supply 40 amps worth of power using only cheaper 20 amp wires. (Since the current can flow over both wires at once.)
But this means that the wires going to an individual appliance are far too small for the main breaker, so each appliance gets a fuse in the plug.
Ring circuits have serious drawbacks, but they helped during a time when there was a copper shortage.
And ever since then the UK has been stuck with huge plugs.
There's also a second reason British plugs are robust and fused: they're built to carry up to 3 kilowatts at 230 volts. (None of your wimpish American 110 volt mains juice here! Nothing quite makes your hair stand on end like accidentally touching a live pin carrying 230 volts and 13 amps ...)
To that end, the live and neutral contacts in a British socket are shuttered. The long earth pin on the plug makes contact before the live or neutral pins are in the socket, and once in contact, raises a shutter to permit live and neutral to make contact. And the nether regions of those pins are insulated so that if a plug is halfway into a socket and something bridges the pins, it can't make contact.
This is a great design -- for space heaters and ovens and server racks. It's a bit less useful for the low power consumption devices that have come to dominate the market (where maximum draw is well under 1Kw -- often under 0.1Kw).
> There's also a second reason British plugs are robust and fused: they're built to carry up to 3 kilowatts at 230 volts. (None of your wimpish American 110 volt mains juice here! Nothing quite makes your hair stand on end like accidentally touching a live pin carrying 230 volts and 13 amps ...)
Mainland european grounded plugs pretty much all handle 15A/230V, and none looks like a battlecruiser (see the well-known and widely used "CEE 7/7" aka "Type E/F hybrid": http://en.wikipedia.org/wiki/File:CEE_7-7.jpg)
And the nether regions of those pins are insulated so that if a plug is halfway into a socket and something bridges the pins, it can't make contact.
That's not really true, you can still get electrocuted if you put you finger on both bolts.
And that plug is massive. Luckily you can use any sticklike thing to allow continental plugs to be inserted (which incidentally I'm doing right now -- hello from Edinburgh)
The L+N pins are insulated half way down so you can't touch any metal part that is in contact with the supply.
The supply terminals are also covered by shutters so you can't put anything in them when there is no plug in the wall.
Australian plugs aren't designed to carry any significant physical weight, as far as I could tell (I was in Melbourne a month ago). The thickness of the live and neutral blades is similar to that of American/Japanese plugs, rather than the round pins common in the EU or the rectangular cross-section pins used in the UK. On the other hand? "Nowhere near as horrible" fits the bill for about 95% of purposes -- because nobody should be expecting a 230 volt mains plug and socket to double as a structural support!
Not at all. NZ plugs are the same design as Australian ones and mine seem quite capable of carrying a reasonable amount of weight - I have never ever seen one of our plugs fail under anything resembling sensible use. They're quite capable of carrying, say, a hefty attached transformer.
And since the pins are angled, even a two-pin version is pretty hard to accidentally wiggle free compared to the two round pin European plug (I think some European countries have extra bits as well that might help?). Definitely does not deserve comparison to the awful American plug design.
It does, however, mean that any type of appliance that you might wish to plug in uses the same plug, regardless of what power level it wants - quite a good example of It Just Works, even if the price you pay is huge plugs.
Of course, that does break down a bit when you get to fuses, since you now have to worry about using different capacity fuses for appliances with different expected maximum power draw (3A for most things, 5A for the odd high-power small appliance, 13A for anything involving a heater...)
Actually, UK buildings typically contain at least three different standard sockets and plugs--the big ugly ones (with a supply of four different fuses needed), a mini version of that design commonly used for table lamps and floor lamps, and a third design allowed in bathrooms so you can plug in an electric shaver (electrical sockets and even light switches are ordinarily barred from bathrooms). There are also many different kinds of lightbulbs (screw-in, push-in, push-and-turn-to-lock-two pins) in many different physical sizes (as well as different wattages). Running a family house requires a considerable stock of bulbs and fuses, which explains all the "electrical supplies" shops which are unknown in the US. Up until about 10 years ago, in my personal experience, UK small appliances, lamps, etc. were sold with bare AC wires and the householder was expected to add the needed style of plug; now everything comes with the huge plugs.
What are these mini plugs? Everything I've ever seen has either the BFO plugs or the wee razor type plugs that go into the BFO ones with an adaptor. I've never seen a socket in a house for razor type plugs (although hotels do have them) - I guess new properties might have them.
Given a choice between US plugs (spark, fall out of sockets, flimsy, dangerous, bendy pins), and UK plugs (Built to last, don't spark, fused, solid) I know which I'd choose.
There's also large advantages to having each plug individually fused - individual appliances blow rather than the whole circuit.
So I wouldn't say we're "stuck with huge plugs". The only real time it's a slight issue/pain is when you go on a plane and the cables take up a bit of space.
> The only real time it's a slight issue/pain is when you go on a plane and the cables take up a bit of space.
I prefer the UK plug too. But you missed one other very important point of pain: the pain of standing on one. As the flex on a UK plug leaves from the bottom, it has the unique property of tending to lay down on the floor with pins facing upwards.
When I was 14 years old, I went through a growth spurt and often passed out when I got up too quickly. One day, I got out of bed in a hurry, passed and and came to lying next to a broken (UK) plug, with a very sore head. It appeared that I had fallen head first onto the prongs of the upturned plug. Looking back, I was lucky not to have done myself a serious injury. A disadvantage of UK plugs versus those in other countries.
Why would the only choice to replace the huge UK plugs be US plugs? This one might make much more sense for example http://en.wikipedia.org/wiki/Schuko given the specs (much smaller, all the same advantages expect being fused - if I understand correctly) and also given the UKs geographic location ;)
Edit: I'd just be happy if Europe picked a single standard and stuck with it. It's ridiculous to have to carry all sorts of converters for what are, in the grand scheme of things, not very long trips.
The Schuko is definitely one of the better designs.
16A at 240V in a grounded plug that is very easy to protect against tiny fingers and that you'd have to be trying real hard to get your fingers on when inserting it, even in pitch dark.
Forwards compatible socket with the Euro plug. (that's the thin, ungrounded one with just two pins, one live, one neutral).
It will do anything from your phone charger to a light duty welder.
> Forwards compatible socket with the Euro plug. (that's the thin, ungrounded one with just two pins, one live, one neutral).
It's not really that it's forwards-compatible, but that the europlug was created specifically for this purpose. It's compatible with all european sockets but the english one I believe.
Yes, they do. Sometimes they'll even spark when they're just sitting there with something plugged in.
There is a mechanical/electrical machining process called spark erosion aka electrical discharge machining. Every time you have a spark a tiny bit of the metal of both contacts evaporates. Of course that's when you want it to happen, in sockets with plugged in loads you really don't want it to happen.
Over time this process accelerates and it has been the cause of many house fires in the US.
The fact that such sockets are placed in walls made of mostly wood placed right next to an upright stud does not help either.
Sometimes they're so bad you can actually smell the ozone.
Everything sparks - it's not unique to american plugs. In the UK the contact is just deeper so you can't see it. If anything UK plugs spark more because the voltage is higher.
And sparks are not the cause of many house fires, you just made that up. The sparks are harmless, and I've never seen a plug with erosion on it. Just because you can do it doesn't mean it actually happens.
No, I did not make that up, and I did not mean 'sparks on insertion' I meant 'sparks while inserted', though 'sparks on insertion' is not good either for your socket.
American plugs spark (much) more frequently and strongly than their equivalent UK/EU plugs because the spring pressure from the side contacts is insufficient to maintain good contact over the lifetime of an installation, especially if the plugs are also worn. The fact that typically the current is twice as high doesn't help either (though if you get zapped it's less of a problem than in 230V installations, the US uses a balanced 110 system for most residential circuits where only a few receptacles which are of a different design have both sides of the step-down transformer outside of the house running to them).
The UK/EU plugs are of a much more solid construction than the American ones, as are the wallsockets they go in to.
I've seen US sockets that made an audible buzz while operating and get extremely hot (hot enough to melt the plastic). Not good.
The usual way in which it gets to this state is that a socket has been overloaded a couple of times, or heavy load is plugged in or removed while switched on, the contacts have corroded or have some soot build up on them and then the resistance increases enough to start a runaway process that ends with the socket failing altogether or with the socket getting so hot that the plastic outside cover will start to melt.
At that point all bets are off, especially in houses that are mostly constructed from wooden sticks instead of brick or concrete.
Another cause of trouble like this is that there was a short period when due to the supply issues with copper electrical wire made of aluminum was tried in residential installations in the US.
These required special fixtures so the wire would not come lose as the aluminum compressed over time thus shrinking away from the contact and causing an airgap and thus sparking.
This kind of wiring is no longer 'code' and if you have such wiring it wouldn't harm to periodically tighten up on the screws to ensure good contact.
Aluminum oxide build-up compounds this problem.
People always blame 'short circuits' for electrical fires, but most of the time this is nonsense, since the breaker will almost always instantly trip in a short circuit situation. That's what they're designed to do.
Half shorts (shorts that are of a resistance low enough to cause significant heat build-up and high enough not to cause the breaker to trip) and faulty contacts (intermittent contacts, sparks and thus heat) are a much more frequent cause of fire.
Another big cause of fire is counterfeit junk hitting the market and do-it-yourself types that don't know the difference using this to wire up that extra socket for a space-heater in the attic.
You must deal mainly with very old poorly maintained houses (rentals?), because all those problems do not exist in normal outlets.
You have soot on your contacts???? Corrosion? Did it rain inside your house?
NEVER tighten aluminium contacts! You will cause exactly those problems that you describe. If there is a problem with it you need to remove it, apply the anti-oxidant paste and reinstall.
But aluminium to the contacts is very rare in america these days, where it does exists it's usually been pigtailed with copper.
I have visited the USA twice this year, and found the power outlets in expensive hotels, serviced apartments, and office buildings to be of a much lower build quality compared to those of my home country, Australia.
In my two months in the USA, I observed more arcs and electrical crackling noises than I have in the rest of my life in AU.
I'll add my anecdotal 2c :it's the same as you. The UK plug is overkill, IMO, but the US plug is downright nasty. The lack of 'off' switches in the majority of them is a problem. I always figured the problem stems from the original design, which was probably a version 1.0, as the USA was the first to get electricity into homes. That's why other countries have superior systems - they had time to learn from the problems and design better systems, with built-in grounds, isolating switches at the point, and higher voltages (220/240 vs 110).
But I could be all wrong, as I'm no expert beyond having a drawer full of adapter plugs.
> You must deal mainly with very old poorly maintained houses (rentals?), because all those problems do not exist in normal outlets.
Rural areas, farmhouses, but one building I lived in in Toronto had a problem (a bad one) with one of the sockets and it was a fairly recent upgrade from what I remember.
> You have soot on your contacts???? Corrosion? Did it rain inside your house?
No, simply an installation from the 70's still operating in 2005. There are millions like that. And I don't live there anymore, I'm back Europe now.
> NEVER tighten aluminium contacts!
Not over-tighten, tighten. You should do it to the proper torque (there are special tools for that).
> But aluminium to the contacts is very rare in america these days, where it does exists it's usually been pigtailed with copper.
Yes, that's the slightly newer method, also since outlawed (and used as a way to fix problems).
The biggest problem I think with the alu wiring was not even that it could not work, but that people would use it with the wrong connectors, the al specific sockets were pretty pricey.
The only place where I know that aluminum is still used in residential wiring is on the entrance wire from the pole to the transformer, usually that's a very tricky connector that uses wedges to make the contact.
If I found myself in a house with aluminum wiring I'd probably rewire the whole thing just for safety. Costly (especially with the US system which staples cables to studs) but worth the peace of mind.
No, I mean don't tighten it at all! Not unless you open it and add anti-oxidant. If you tighten it you break the air seal, and allow it to oxidize, and aluminium oxide does not conduct.
The correct installation uses anti-oxidant to seal it, then you tighten it enough to crack the aluminum oxide, and the anti-oxidant protects it. If you tighten it without fresh anti-oxidant you are creating a hazard.
And pig tails are not outlawed - quite the opposite, they are the recommended way to handle aluminium wiring.
> No, I mean don't tighten it at all! Not unless you open it and add anti-oxidant. If you tighten it you break the air seal, and allow it to oxidize, and aluminium oxide does not conduct.
Ah ok, I see what you mean now, yes that makes good sense.
As for the pigtails, as far as I know you can not make any new wiring with Aluminum in residential installations, pigtailed or not (I left my code book in Canada because it is of no use to me here, maybe there is some up-to-date online resource). Industrial use is still ok I believe.
Unfortunately yes. As a Brit living in America, every time I have to deal with a plug socket I feel ever so slightly like I'm about to electrocute myself. Sure, the big bulky plugs are a pain to carry around, but at least I felt safe using them.
Wow, so self-delusion is alive and well in the UK!
"The only time its a slight issue"???
How about manufacturing, shipping, selling, storing, repairing, and paying for that overdesigned eyesore? How about looking at it? How about moving the couch out from the wall so the dang thing will fit back there?
* trip up a cable, and the plug falls out of the wall
(Pulling a UK plug out required force. It will not pull out)
Plus the cable exits a plug pointing downward, which
means it will not pull out via the cable.
* Sparks when you put a plug in or out.
* Bent pins that look like they're about to drop off
* No shielding on pins
* Often no mechanism to stop things being put in sockets
(All UK sockets only open once an earth pin has gone in
I wonder what the incidence of electrocution is in the UK vs US. I'm probably biased, but I certainly feel far safer here, especially having kids.
> * trip up a cable, and the plug falls out of the wall
> (Pulling a UK plug out required force. It will not pull out)
> Plus the cable exits a plug pointing downward, which
> means it will not pull out via the cable.
This one is a mixed bag (trip up a cable, throw the expensive grandma lamp to the ground).
> * Sparks when you put a plug in or out.
Not at all. Euro plugs earth pin always makes contact first.
> * Bent pins that look like they're about to drop off
Bent pins? UK plugs are only marginally sturdier.
> * No shielding on pins
What use is it?
> * Often no mechanism to stop things being put in sockets
> (All UK sockets only open once an earth pin has gone in
All euro sockets have plastic spring-loaded linked stoppers that prevent accidental insertion of random stuff into the holes, and insertion of anything in only one hole (you need to push both sides together).
Lamps seem very prevalent in the US. Why do most apartments I've been in not have ceiling lights? WTF? When I lived in the US I'd go in a room and spend a while finding 4 lamps and turning them on. Same in hotels.
Also, when you decide to put a lamp somewhere, you typically make sure the cable is not somewhere that can be tripped up.
But as I say, all rooms in the UK come with a fitted ceiling light, and a light switch by the door. So lamps are less common.
Even though I currently live in a U.S. apartment where the main rooms have no light fixtures (though they do have switched outlets), past experience hasn't shown a trend of not having light fixtures. Additionally, newer construction seems to have more fixtures, not less. This thread seems to be a circus of alternately overstating and understating problems though, so I'd take it with a huge grain of salt.
So you're saying that if you trip over the cord while your hair dryer is plugged into an American socket, it doesn't fall off of whatever ledge it's on? Do you use an industrial hair dryer or something?
Just FYI, the US NEC requires each entryway of a room in a dwelling to have a switch which can control a light.
It is usually, but does not have to be, an overhead light.
An alternative that is also code-conforming is to have the switch control a socket (typically, the bottom plug in several duplex receptacles in the room) where a lamp is plugged in. Sometimes people don't actually plug a lamp in there, so the switch does nothing, and maybe that's what you've been irritated by.
If the wiring is done this way -- e.g., bedrooms and living rooms -- it can be quite flexible if you want to rearrange the room layout. You move the furniture and plug the lamp into the bottom receptacle where-ever it is convenient and sensible.
> I wonder what the incidence of electrocution is in the UK vs US. I'm probably biased, but I certainly feel far safer here, especially having kids.
Cars kill 100 times more people than electrocution (not to mention severe injuries, which are rare for electrocutions), so they're probably a more important risk to worry about. Any slight difference in car accidents is going to swamp electrical concerns.
I just meant that as far as comparing the US to the UK for feeling safer (his words), electrocution concerns are pretty trivial. Unless he spends an unusual amount of time near wall sockets or suffers from an acute case of electrophobia.
According to (http://www.faqs.org/faqs/electrical-wiring/part1/section-20....) and to the wiki article on wire gauges, 40A requires 8-gauge wire, which is 3.264mm in diameter, while 20A is 12-gauge, which is 2.054mm. The ratio of their cross-sectional area is 2.53; this justifies that the 40A wire conducts twice as much as the 20A but has 2.53 as much area, thus being more costly.
I'm not sure why. Is the skin effect sufficient to explain this?
Yes, a ring circuit you run a single wire around the room and back to the fuseboard. With a spur circuit you run a single wire to the furthest plug.
In a typical room going back to the fuseboard isn't much further so it's not twice as much wire - more like 10% more
I think that's simply so that the wire runs parallel to the wall instead of sticking out at 90 degrees. Without a movable part it's hard to have one feature without the other.
This is a common complaint. I wonder where people are leaving their unused plugs that they constantly tread on them? Probably not in a storage box/drawer.
The promo shots of the final working model don't show how you get at the fuse, but I'd be very surprised if it has been overlooked. I suspect it's something to do with the red dots.
> The promo shots of the final working model don't show how you get at the fuse, but I'd be very surprised if it has been overlooked. I suspect it's something to do with the red dots.
Indeed, the red dot is the plug cover. This set of blogspam pictures don't show it, but previous sets (the folding plug first made rounds in mid-2009) showed how the plug works. You can see an "action shot" simulation of the plug in the video: http://www.youtube.com/watch?v=f6DvjKkGT6s#t=1m46
Why not have socket fuses like you can find in bathrooms sometimes? I'm not arguing history, instead I'm just curious if there's some latent advantage to putting that hardware into the plug. All I can see are losses in convenience, duplication of effort, and weakened robustness.
Different plugs will have different fuses appropriate to the type of device. I have no idea how much of a benefit this is but you couldn't do that if the fuses were in the socket.
They tend to rest on the plug's back, and hurt a lot when you step on them.
> Any other countries use them?
India and South Africa use the so-called Type D plug[0] (also called Type M in its 15A incarnation), which is similar but uses round plugs (type D is actually an older english standard). Some other south-east asian countries also use Type D. The english plug is called "Type G" and used in a number of former colonies and protectorates[1], especially in Africa and the Middle East.
The reason plugs in the UK are so big is that each one must be individually fused. And the reason for that is something called a "ring circuit".
In a ring circuit you have, say, a 40 amp fuse at the mains/box. From this you send out two wires, each rated only for 20 amps, going in a circle around the house. You can now supply 40 amps worth of power using only cheaper 20 amp wires. (Since the current can flow over both wires at once.)
But this means that the wires going to an individual appliance are far too small for the main breaker, so each appliance gets a fuse in the plug.
Ring circuits have serious drawbacks, but they helped during a time when there was a copper shortage.
And ever since then the UK has been stuck with huge plugs.