Have you ever wondered why power plugs have the shape they do? The common American Type A design dates back to the original 1920′s two-pin plug design. Why are we still using 1920′s technology to power electric devices when virtually every other household technology has experienced rapid change and evolution?
It turns out that everything about electric wiring is strictly controlled by the National Electric Code, a national standard that is reissued every three years or so, but has changed so little, that aside from various safety devices, a 1960′s code book is virtually the same as a new one. Many, perhaps most, electricians are content with the standard 120V/60Hz/15amp 3-prong socket, but I would beg to differ.First, the 3-prong, triangular plug is unnecessarily large. Using a flat plug design with two circular prongs and a ground in a groove would shrink the size of power plugs to a tiny fraction of their current size. (For somewhat superior standards, check out the European B, C, or SE plugs.) Second, the 120V/15amp current is either too strong or too weak for the majority of consumer devices. Most households use three types of devices: a few power-hungry home appliances such as dishwashers, vacuums, air conditioners, and disposal systems that need 240volts, medium to low power devices such as computers, speakers, and TV’s, and many very low power consumer electronics such as CD players, cameras, and computer accessories that only need 6-12V and 1 amp. The 120V standard is too weak for the large devices (your vacuum cleaner is limited to 12amps, for example) and is too much for small devices, which require a large transformer to use the power.
I am neither an electrician nor an economist, but I think it is likely that the enforcement of a national electric code has prevented innovation in this area. In developing nations, it is common for a single building to have multiple power sources with differing voltages, and plugs that support several different standards. Certainly, an electric code has many benefits in such cases, but when governments get involved in the construction code business in the interests of “safety,” the consequence is often technological stagnation. The case is aggravated by the fact that the code covers the United States and Canada, and thus prevents interstate differences which could introduce competitive differences.
Faced with a regulatory barrier on the construction side, entrepreneurs have introduced some innovations on the consumer electronics side during the computer revolution. A standard set of voltages has evolved for low-power devices, so that most transformers are interchangeable, and there are kits with universal adapters for devices in the 6-12V range. The creation of a power standard from an auto cigarette lighter is another example.
A recent development has been the proliferation of Universal Serial Bus (USB)-powered devices, despite the fact that a USB port is limited to 5V and 500mAmps. I own a USB-powered mouse, keyboard, camera, joystick, webcam, and an auto-USB adapter, and there are USB powered coffee mugs, lights, hard drives, nail buffers, Christmas lights and trees, disco balls, aquariums, and god knows what other kinds of devices. In effect, USB has become a de-facto global standard data and power standard that has overcome regional electrical regulations. There are over 1 billion USB devices in the world, and that number is sure to grow.
Nevertheless, leaving the evolution of electric wiring codes up to the market is likely to create power standards we can only dream of today. Imagine having a dozen tiny, flat plugs on every wall socket that power everything from a vacuum to your desk lamp to your keyboard and contain in-wall power cables that can be pulled out to connect to any device. Because these devices could transfer data as well as power, each plugged in device would register its power requirements and capabilities on the home computer, which could then remotely control them and manage overall household power usage. A printer, webcam, or TV would be connected in the living room and network with a computer over the power line. Bulky transformers and separate power cords would be history, and electronic devices would shrink because external power sources would automatically adjust to their needs. All the components for this technology exist today – but attempting to integrate and mass produce them in households would be a legal and regulatory nightmare.
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well i am an electrician and the national elec code changes every 3 years and there has been around a 1000 changes since 1980 every three years. and along with those changes we now have the gfi plugs and now arc fault breakers, yes they do cost some money. and the list goes on…
My wife is from Malaysia and is over there now and we are going thru immigration now and that is a nitemare, but trust me over in Malaysia yes they opperate at a 240 volts system but it is a nitemare. yes we should be at a 240 volt system but that is not going to happen now, impossible i think. Unless you want to totally redesign the whole elec grid of the US? see the wiring can stay but you would have to rip out all the transformers, period. and then all the breakers and so forth. Hmmm talk about needing more electricians and quick. i could really be making some money.
“Unless you want to totally redesign the whole elec grid of the US?”
Well, that’s part of the problem isn’t it. If the eletric grid was something that emmerged spontainiously out of natural market processes instead of top-down control comand economy style, it would be much easier for some enterprising entrapreneur to try his hand at alternatives.
Tracy
Roger:
Could I install transformers and outlets in my house that give my 6V/1A DC? So that I could plug my low-power devices directly into the wall without need of external transformers? WHy couldn’t the transformer be *behind the wall*, with a little round outlet like is found on my portable CD-Player? If I wired my house like this, would I bring the wrath of the Inspectors down on my head?
IANAGN (I Am Not A Grammar Nazi), but come on, really:
Second, the 120V/15amp current is either to strong or two weak for the majority of consumer devices.
Tracy the nation would have to totally do away with all the 240/120 volt transformers you see on the poles or on the ground that feed houses.
In some commerical buildings and a lot of industrial buildings they use 3 phase power which would come in at 480/277volts and then inside have a big step down transformer that is feed from the 480/277 volts and off to the side a 240/120volt electric panel to feed the outlets throughout the place. LIke computers and so forth. Since most of our appliances are wired for 120 volts, then the manufactures would have to redesign them for 240 volts. Do you realize how much money this would cost? Would you want to go out and purchase all new appliances, and light bulbs and so forth?
I am not a power grid expert. Just that yes the wiring could still be in place but almost everything else would have to change and that is just not gonig to happen now. If the electric system was first being formed here in the USA and also everything else then yes it would have been the smart thing to use a 240volt system as with appliances work much better at 240 volts than at 120volts. Much more efficient. So that is why at houses on central air cond.s they use 240 volts and not 120. As with the higher voltage you use smaller wire as the units work much better and draw less amps,(power). MOre volts and use less amps.
There is now being use a lot of low voltage lighting systems in houses, like some of the recessed lighting and undercabinet lights some times are lowvoltage. That is they use 12volts to power them. they have there own little transformer in the unit.
and tracy a top down command? Do you really know how many people sit on those commities to see how to change the elec code when the time comes every 3 years to submit changes? That is the national electric code is put out by the nfpa. it is made up of hundreds of different org,s and i can or you can if you knew how to, could submit changes, there is a form to be able to do that with the NFPA. Since the new elec code is coming out now, there is a time period to submit changes to around Nov of this year and then the code change panels will look over and see what if any should be changed. There is usually about a 1000 changes that go into the code every three years.
I don,t know how to answer your question at this point electo-heretic. and i do sometimes have to deal with elec inspectors and most of them are nice but don,t impress me about house wiring in some ways.
In the vast majority of towns and cities and counties, electric companys are given a monopoly on the production of ellectricity. If monopoly statis isn’t a Recipe for an industry to stagnate I don’t know what is.
The Foundation for Economics Education has done several research projects on making the production of electricity actually free market.
See for instance
http://www.fee.org/vnews.php?nid=3898
Tracy
The first computer I had, a Tandy Color Computer, had a serial port on the back. RS-232 compatible (voltage and protocol wise) but it used a rather non-standard connector—a 4-pin DIN plug. My next computer, an IBM PCjr, also had a RS-232 compatible serial port on the back, but it used a 16 (or 26, don’t recall) Berg type connector.
The 4-pin DIN plus wasn’t all that common, but I was able to make a 4-DIN male to DB-25 male cable. IBM provided an adaptor for the IBM PCjr, one end being the Berg type connector, the other end being a DB-25 male connecor (more or less the “standard,” although why IBM just didn’t put a DB-25 male connector on the end to begin with I do not know). My Newton has a serial port, but it’s a subminature DIN port with an odd pin out. My first digital camera had a serial port, but it too had a subminiature DIN port with its own pin out.
I have piles of special one-off serial cables, adaptors, gender changers and testing kits just for the sole purpose of getting a device with serial port A to talk to another device with serial port B (and it wasn’t uncommon for me to string three or four different cables and adaptors to connect these serial devices together).
Another story.
I had a job at the university I attended. My office was in a new building which was wired for a particular network technology—10Base-2. By the time I was leaving a few years later, money was being spent to rewrite the building for 10Base-T. Wouldn’t surprise me if they had to rewrite for 100Base-T (100Base-T can use the same wiring as 10Base-T, if and only if the wires meet a certain electrical specification). And now optical fiber is becoming the hot new network base, so that’s yet another rewiring.
Now, what was the question again?
The most likely answer is: none. They sell into international markets anyway, and AFAIK the entire world outside the US uses a 400/230V (i.e., 400 volts phase-to-phase, 230 volts to ground), 50Hz domestic supply, so they’d save money not having to build stuff just for the US market.
“Unless you want to totally redesign the whole elec grid of the US?”
Well, that’s part of the problem isn’t it.
precisely, but rather from the perspective that power generation should have always been decentralized (which is another way of saying not a national “command economy”).
hence why the power system is a nightmare, teetering on the edge of far more black outs than were experienced not so long ago; it’s the “hub and spoke” design of central authority and planning. stir in one cup of really half-assed “deregulation” and a defacto moratorium on nuclear fission power.
but the market change can begin with YOU. google for “microturbines” sometime and discover how for the price of a very modest automobile, your entire home and possibly a few of your neighbors can have electricity generated (at whatever volts/amps/phase you desire) by a device as large and loud as the average refridgerator, for a considerable long-term ROI and an adjusted fraction of environment damaging externalities compared to most power companies.
-z
if i was designing an elec service for a country that did not have any electric then i would design a 24o volt system, but the USA is stuck with what we have, period. It is not going to change and are any of you all electricians? And also Japan is on a 240/120volt system too, i believe. yes most of the rest of the world is on a 240 volt 50 hertz system. And also the national elec code is put together by mostly those in the elec trade and not by the government nut cases in Washington. want more power then build more power plants. see how far you get with that one, ha see how many regulations to deal with. And that is part of the problem, not just because we are on a 240/120volt system.
so peter do you want to rip down all the 240/120 volt transformers across the usa? every one of them that feeds houses must go then. and redo some things in the house to. Who is going to fork over the money for that?
It wouldn’t be necessary to rebuild the entire electricity supply grid for the US in one moment. The distribution system already runs at a higher voltage, with down-transformers converting to 110V for every few houses, for example; you could just replace those, one at a time, to convert small segments of the system (even individual homes). [Of course, those people would have to buy "foreign" 230V appliances (and metering equipment!), or put "travel transformers" on everything...]
I just don,t think it is every going to happen in my lifetime. And i have been in the electical trade since Aug1978.
A few years ago a couple we were doing work for bought a bosch clothes washer. It was with a 240volt elec plug. So i had to redo the elec outlet from a 120 volt plug to a 240 volt outlet. A clothes washer plug is suppose to be on it,s own circuit and years ago it did not. Now if that couple had been at an older house and had been a house that had its basement sealed off then i would have been pulling my hair out trying to figure out how to get a new 12/2 romex cable to the clothes washer outlet.
As i have said if the USA was just now designing an electric system for the whole country then we would want it a 240 volt system. To late now, and the national elec code is put out by the nfpa. and not the federal government and it has changed a lot since i have been in it. The national elec code is a saftey book with minumium standards. I like the code book and glad it is there. Go see the elec work over in Malaysia. Talk about scary. Have you seen how big the elec plugs are over seas. Like in Malaysia. Must be just about twice as big as they are here.
Now just trying to change a few transformers at a time, just don,t think that would work. Yes Peter the distruption system is much higher at around 13000 volts that feeds those house transformers. Now can,t you see those who move into those houses and having to buy all new appliances. etc. Also there elec panels i think would have to have all there circuit breakers replaced to the 240 volt types and Some elec panels and circuit breakers they have not made in years. Like the federal pacific breaker panels. etc.
The USA was no all standardized only a few decades ago.
In some regions 120V Direct Current was used. That’s what all those 120V AC/DC universal motors were sold for when AC induction motors are much more efficient. Incandescent bulbs work about the same on 120 V DC as on 120V AC.
120V receptacles have changed in my lifetime. They used to all be non-polarized – both slots were the same width. Then the polarized receptacle, which accepts both polarized plugs and non-polarized plugs, was introduced. Now the polarized receptacle with a ground prong plug-in integrated is standard.
The house I grew up in has polarized/20ampere slots without ground. The 20 amp slot is the horizontal slot so a combination outlet has a “T” shaped slot for both 15 amp and 20 amp plugs (I have never seen a 20 amp plug).
Our 120/240 VAC system used in home and small business is 120 volts between each conductor and common (ground) but 240 volts between the conductors. 120V convenience circuits simply use one side between “hot” and ground.
In some northeastern regions besides direct current (0 Hz) there used to be 25 Hz systems that obtined their power from the electric railroad power plants, which ran at 25 Hz (cycles per second) rather than the 60 Hz used today.
There is simply no advantage to changing over to 240V 50 Hz sufficient to justify the cost. Electric equipment is made in such immense quantity for each market that there is little if any economy to make all equipment to the same standard. USA/Canada and Japan, both very large markets, are 120/240V AC 60 Hz. Also central Mexico is to this standard, I think.
It’s sort of like the UK, Ireland, Japan, India and a few other nations that drive on the left. Sweden changed over in 1965 but the others will likely never change as it would require a partial rebuild of highway interchanges besides repainting all the roads over night and changing the traffic signs and signals.
Then, for many years the motor vehicles would be nonconforming as the life of right hand drive vehicles would be probably in excess of 15 years before half had been scrapped.
Here in the USA we have seen a gradual standardization of many systems – in 1861 there were more 5′-0″ gage railroad miles than “standard” 4′-8 1/2″ but Congress chose 4′-8 1/2″ for the Pacific railroad so from then on the conversion was rapid. When the Union would conquer a region of the South it would regage the tracks to “standard.” Yet Russia, Finland and some others remain 5′-0″ gage while India, Pakistan, Spain and Portugal stick with 5′-6″ gage. Ireland remains 5′-3″ but 5′-3″ in Australia has been changed to 4′-8 1/2″. Japan is mostly 3′-6″ like South Africa and other southern African countries but the Shinkansen (Bullet) trains are 4′-8 1/2″.
Full standardization may never come to pass as there is insufficient advantage to worldwide standardization to make it worth the expense and inconvenience.
Pete
Have you seen how big the elec plugs are over seas. Like in Malaysia. Must be just about twice as big as they are here.
Malaysia uses British style plugs, with a 13A (I think) fuse integral to the plug. Not all 230/240V plugs are twice as big as US ones. NZ/Australia use plugs that are just like the US ones, except that the pins are canted at a 45° angle.
Also there elec panels i think would have to have all there circuit breakers replaced to the 240 volt types and Some elec panels and circuit breakers they have not made in years.
But they are made — for all the non-US countries that already use 230V supplies!
But I agree there’s no particular reason to do it, and it’s unlikely ever to happen.
The point I took from Mr. Veksler’s remarks is that heavy-handed central command and control of the US electrical system has impeded innovation and progress. I have to agree. None of the objections raised in the various comments address that central point.
The objections regarding practicality miss the point entirely. If the existing regulations were to be removed or considerably relaxed, the normal functioning of the market would decide if transformers were replaced or outlets changed. Either consumers would find the new products worth the cost or they would not. Manufacturers would learn from their profits and price signals what innovations were acceptable and which were too costly.
I cannot claim to know what voltage or other aspect would change. Statements claiming that the nation should/would select a 240 volt standard have not been supported, and demonstrate a mindset disposed to central command. I find these claims particularly amusing as the current residential standard is already 240 VAC, 60 Hz. The voltage is split into two 120 volt circuits inside homes, which is why you can have both a 240 volt dryer outlet and a 120 volt outlet from the same basic service.
I would guess that a deregulated market would incorporate many different lower voltage services. Low voltage lighting is already popular. Computer chips are going to ever lower voltages, with 3.3 volts and 1.8 volts already commonplace, and 1.2 and even 0.9 volts contemplated. It’s expensive in copper and space to move lots of power at these low voltages, but the price of conversion is dropping rapidly. Already there are truly universal products, such as welders, that can be plugged in pretty much anywhere on the planet. They work on both 50 Hz and 60Hz, and accept any voltage between 200 and 600 volts. Many (but not all) computers also incorporate universal input voltage power supplies.
Some homeowners, perhaps those with small children, might opt for a voltage of 40 or 50 volts, low enough to greatly reduce the chance of injury from accidental contact with electric conductors. Others might object to the cost of the heavier copper cables, or the cost of conversion, and stay with the present 120/240 standard. Appliance makers already are incorporating advanced power conversion technologies in their products. (There is an Italian washer that include a 50 MIPS digital signal processing chip, turns single-phase power into 3-phase so that the motor is more quiet and efficient than present units.) Left to their own devices, consumers and manufacturers would quickly determine what features and prices were appropriate.
The National Electric Code is certainly one of the most effective tools of statism in this arena. The minutia of “1000 changes” every 3 years supports statist requirements for licensing of electricians. Most of the licensing test involves being able to repeat the various nonsensical drivel that is written into the NEC. The document is so poorly written and self-contradictory that there is an entire industry devoted to “interpreting” the rules. It fails the test of any free-market standard in that a reasonable, knowledgeable person cannot read the standard and know how to comply with it. Its primary use is to reduce the number of electricians, thereby raising their wages, and to give local code inspectors essentially arbitrary authority that can not be appealed or resisted. The code is so poorly written, and the enforcement so arbitrary, that an inspector with an agenda (or merely lacking a clue) can add thousands of dollars to the cost of any construction project. Removing the NEC would be a great advance for liberty, property, and free markets. Insurance companies and other free market actors would quickly fill the few useful functions presently arrogated by the NFPA, and the price of electrical work would plummet.
I commend Mr. Veksler for raising an interesting and often negelected topic. Thank you.
When I had children, I had to install plastic safety plugs in all unused outlets. I found out later that many European designs have a little shutter built into the outlet that prevents children from sticking paperclips, toy sissors, etc. into the outlet. Being an electrical engineer I looked into this further. The European plug design has a hood to prevent your fingers from contacting a live prong as you insert the plug. The ground pin raises the shutters after the hood portion of the plug cuts off access to the prongs. The ground pin then makes first contact ensuring the equipment ground is connected before the power handling prongs become live.
In the US we use 240 volt transformers with a center-tap. This allows either 240 volts AC or 120 volts AC to be distributed. To balance the windings, about one half of the expected 120 volt load is connected to each leg. Either 240 VAC or 120 VAC is enough to kill a person especially since the 60 Hertz (cycles per second) is a frequency prone to disrupting the rhythms of the heart. Stick your tongue on a 9 volt battery and you will find out that even 9 VDC can hurt (don’t really do this – take my word for it).
There don’t seem to be standards for voltage in the US. I was told by one power company executive that they aim for 1) 120 VAC at the distribution transformer, 117 VAC at the breakerbox in the house, and 115 VAC at individual outlets. These are the target voltages under normal load. When you have no significant load in your home, you might expect to measure 120 VAC on an outlet. There also is not a guarentee to the consumer for frequency deviation but the power companies adjust their generators so that 5,184,000 cycles occur each day which keeps clocks running accurately.
Using 240 VAC for normal outlets would allow one to use a smaller guage of wiring to achieve the same amount of power distribution to outlets. Since power equals voltage times current and the drop in the wiring is current squared times resistance, the current required is cut in half and the wiring resistance can be increased by four times. This allows you to cut the amount of copper to one forth of what had been used.
In summary, we could improve safety and decrease wiring cost by adopting European approaches to power distribution.
My question is:
When did the US code change (specific date?) to require small appliances to have polarized plugs? Does anyone know? Did the sockets come first or was everything required to change on the same date?
Thanks for the info in advance.
My question is: Will a Europen standard (from Germany- 230V) dryer work on 220V in the US if the plug is changed, wired correctly?
My answer to the cost argument is that every year each of us probably buys 20 devices that require a low-voltage ac-to-dc adapter (“Wall Wart”) to make it work. Many other appliances have internal transformers. A salutary effect of privatizing (as opposed to phony ‘deregulation’) electricity would be that a competitive power industry would have firms that can make profits by catering to their customer’s needs for various voltages. Codes are fine as far as they promote safety, but they are lousy at promoting economy, and should be changed to reflect this truth.
I am not an electrician however I have wired several houses with 200 amp services. I would be grateful if someone can answer my questions? Other than the issue of cycle rates, I thought the two systems were similar? I thought the difference between the North American and European electricity system was that in the American system we split off each side of the alternating cycle to have 120volts on each side of the service panel. Most electrical services in America have 240 volts brought in from the street via two conductors. Is the electricity in Europe a 120v / 240v OR a 230v / 460v system of secondary supply system?
In Canada, primary distribution varies depending on location? (E.g. 10,000v, 13000v, 20,000v) Transformers on the street drop this voltage down to 120 / 240v……
In my house in Europe, could I not simply wire a conventional 3/14 appliance kitchen receptacle off each side of the alternating cycle of a European service panel? I have thought of doing this.
Thom Collier, Lillooet BC
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