Hey folks!  Let’s talk about some Everyday Mysteries — things that we encounter all the time but don’t really understand!  You can either ask about something here, or posit your own explanations to common but commonly-unknown things!

Today’s featured topic has kind of vexed me for most of my life:  What’s with all the variant types of power sockets and plugs in the world??  Anyone who’s traveled internationally at least once understands this frustration — it’s a common complaint.  “Hey, I just want to plug in my laptop, what’s with all these weird and scary shapes?  Will I electrocute myself or burn the place down if I plug this in wrong?  Why does this outlet look like it just lost its best friend?”  Travel adapters exist, of course, but they’re unwieldy and cheaper ones don’t do voltage/ampere/frequency conversions that some electric appliances require.  Why can’t there just be ONE type of plug and socket?

Well, it turns out that the world was not electrified in any particularly orderly manner.  Yes, it was mostly conceived in America and adopted in waves across the world from there, but in the beginning, electricity was only used for electric lighting.  While the Edison screw (ES) socket is more or less the world standard for light bulbs (except in former British Empire areas — damn Brits always gotta be different), electric appliances came around rather later, and since homes were initially only wired for lighting, the earliest appliances had to be screwed into a chandelier (meaning your light bulb had to be temporarily displaced).  Different inventors in different countries eventually came up with different ways to plug appliances into the grid through other, more convenient and accessible means, but almost nothing was standardized in the first decades of the 20th Century.  It wasn’t until the interwar period (1920s-30s) that national regulations for standardized plugs, sockets, voltage, amperage, and frequency became uniform in developed countries, and those countries’ current and former colonies and trade partners in the developing world tended to adopt whatever they had access to.

So one can basically look at a snapshot of the most developed countries in the world circa 1950 to get a general sense of how many standards developed: America and Canada, France, Germany, the United Kingdom, Denmark, Russia, Switzerland, and Italy all developed their own, mostly incompatible plugs and sockets, sometimes in waves (and sometimes, when those countries developed newer standards, the older ones still continue to exist in other places).  And while there has been some marginally successful attempts at convergence, it’s still a headache for a foreign traveler, or someone who wants to buy an appliance built in another country with a different standard.

To help simplify things, the International Electrotechnical Commission (IEC) in Switzerland assigned a series of letters to the most widely-used plugs and sockets:

• Types A and B are rated at 100-125 Volts and are found in North America, much of northern South America, Japan, and the Philippines, and are standardized by the National Electrical Manufacturers Association (NEMA); while the old Type A sockets (two pin, ungrounded) have been deprecated and are not found in modern or updated buildings, both Type A and B plugs are common, and Type A plugs fit Type B sockets.
• Type C is the “Europlug“, an ungrounded, low-amp plug that can fit many different types of 220-240 Volt plugs across the world (E, F, H, J, K, L, N), provided the appliance is “double-insulated” (which most laptops, phones, etc. are) so that the polarity of the pins doesn’t matter (i.e., it can be plugged in in either direction without problem).
• Type D was developed in the UK in the 1930s, and while it still is in some use there, it’s most commonly found in former British possessions in southern Asia (India, Pakistan, Myanmar) and much of Africa.    (See Type G for the current British standard.)
• Type E was developed in France, and is still used there, Poland, and former French possessions in Africa.
• Type F, also known as “Schuko”, was developed in Germany, and is still used there as well as Spain, most of Eastern Europe, and western Asia.
• Note: most newer installations in Type E and F countries use what is called a CEE 7/7 plug that is designed to take either type, as well as the Europlug (Type C), which allows cross-compatibility of most lower-power appliances throughout almost all of continental Europe.
• Type G is the modern standard in the United Kingdom, as well as Ireland and various countries throughout Asia and Africa.  Due to its large size and thick, blocky pins, it’s the most difficult to adapt.  It is one of the few plugs that is required to have its own internal fuse.
• Type H is a design used exclusively in Israel.  The newer Type H standard in use almost everywhere, which uses round pins vs. the older flat pins in older installations, accepts the Europlug which makes Type H adapters mostly unnecessary.
• Type I is used in Argentina, Australia, China, and Oceania, and is an adapted form of a now-deprecated standard from America called NEMA 10-20.  Despite the plug and socket being the same shape in all Type I areas, the hot and neutral pins are reversed in Argentina, versus those in Australia, China, and Oceania.
• Type J is used primarily in Switzerland and Liechtenstein, as well as Jordan and a few places in Africa.  The Europlug is compatible with these outlets.
• Type K is used in Denmark, Greenland, and a handful of other global locations.  This is also compatible with the Europlug.
• Type L is used in Italy, Libya, Chile, and Ethiopia, and is also compatible with the Europlug.
• Type M is a larger-sized, higher-amp variant of Type D that’s used in many (but not all) of the countries using Type D.
• Type N was created as an attempt by the IEC to create a truly standard electrical socket for countries using 230 Volt electrical grids; it has only been adopted in Brazil and South Africa, and is compatible with the Europlug.

Of course, these letter codes are not meant to be an exhaustive list of all of the different plugs and sockets currently or formerly in use in the world. Thailand has their own type of plug that is informally referred to as “Type O”, and the former Soviet countries have a smattering of various standards still used in certain applications to this day (though both areas also are generally compatible with the Europlug).  And this article only includes plugs and sockets for alternating current (AC) power — there’s another whole list of DC connectors that I’m not even gonna get into!

Interesting(?) bit of a tangent:  NEMA itself has a wide variety of plugs and sockets for different uses, based on voltage and amperage.  The most familiar to us are the Type A (NEMA 1-15: two-pin, ungrounded) and Type B (NEMA 5-15: three-pin, grounded), which are both for electrical supplies running at 100-125 Volts at 15 amps.  However, some appliances require higher voltage and/or amperage and therefore have their own sockets with different pin layouts that prevent the wrong type of plug to be inserted.  For instance, offices and warehouses are usually equipped with NEMA 5-20 sockets (versus the 5-15 sockets found in residential homes), which can support either 15 or 20 amp appliances (look for the T-shaped neutral pin hole), and modern homes are equipped with a 14-30 plug (carrying both a 120V and a 240V supply at 30 amps) for clothes dryers and a 14-50 (120/240V, 50 amps) plug for electric ovens.  Some older homes still have the deprecated NEMA 10 plugs for dryers and ovens, though it’s possible to get new appliances rewired with a separate grounding wire to adapt to these — I once had to do this with my newish dryer when I rented a house built in the 1960s and it was fairly simple to do.

Various others are shown here:

 

TL;DR?

The best takeaway from this is, if you’re from North America and you’re headed overseas, your best bet is bringing a Type A-to-Type C (Europlug) adapter and making sure your small appliance (laptop, phone, etc.) supports different voltages, amps, and/or frequencies, which almost all modern ones do.  If you’re a true globetrotter, though (or you’re heading to the former British Empire countries), you might want to spring for one of the “universal”, fancy ones that do all the conversions for you no matter where you go… a really good one with USB outlets included will run you about $25-30.  These are also useful in places where older, less inter-compatible sockets are still prevalent as well (looking at you, Italy!).

Safe travels and bon voyage!