After observing the light bulbs, fixtures, and ballasts that come from most countries in the world, I have seen that most countries in the world adopted European specification lighting. Why did most countries adopt such lighting?

I would guess because most of the world went for the superior European electrical system, mainly the home voltage system of 3x230/400V means way cheaper infrastructure and being more versatile than the US 2x120/240V one.
The thing is, the 2x120/240V (or hypothetical 3x120/208V) can not be wired for longer distances than some 100 feet or so, so each consumer needs his own transformer. And that gets very expensive, both to install, as well as in energy losses (mosr transformers are just idling). And it means for normal homes the full 3 phase service is out of reach, so all the higher power machinery (AC's, shop machi ery,...) have to use heavier, more complex, less reliable and definitely more expensive single phase motors. Higher power demand businesses get 3 phase power, but because many medium appliances are already designed for single phase, it forms a mess of incompatible voltage systems within that single building (120V vs GND, 240V across phases, 3x208 vs GND, 277V between phases at least).

With 3x230/400V system the voltage is high enough so it could be wired for a few km, so just a single transformer is needed for the whole district.
That means there is no cost burden to feed all homes with the complete 3 phase power, which can be then used for single phase 230V devices, plus all motors could already use 3 phase feed, so be of very simple, more compact so way cheaper construction, so already 300W motors were already installed on 3 phase because of that.
And the 3x230/400V is already sufficient to power even 100's kW machines in an industrial installation, so unless going to MW range loads, all from small homes use the same 3x230/400V voltages (small 230V outlet then just need corresponding protection devices, but that can be tapped virtually anywhere on any high power line, no need for any transformer).

And why the north america is still using the inferior system? It is just the legacy standard problem. Technically if they swith to the 3x230/400V, all installation would be simpler. But the problem is, the 120V installation already exist and it is wide spread. So transitionning to 230V would mean for some time (and that would be many decades, in Europe the transition period for the few places that had 120V-ish service took 50 years to complete) there would be both completely incompatible systems in use in parallel, each somewhere else. So the transition would be so expensive and complicated, it would be less and less likely to happen.

The thing is, the US systems were born at a time there was very little of technology and knowledge available, so many choices they had to make turned out to be bad ones after few decades. A single conversion happened (DC to AC service), but at that time it affected minimum appliances (most were lights or small heater where it does not matter, small series DC motors could run on AC as well,...), but since then the system was just spreading across the nation. If the bad choices (mainly regarding the voltage) were eminent, the 120V service was so much spread it was too late.
The mass electrification in Europe happened more than half century later than the US. Plus in the meantime there were two major war destructions. So only after WW2 the grid was build nearly from scratch, so the standards could learn from weaknesses and bad choices made. Plus they could already rely on technology advancements. Because the older installation was limited and in many cases already destroyed by the war, it was way easier to build the infrastructure with all the lessons learned and without dragging all the bad historical decissions, just ignore the older systems and transition the customers to the new system.
Now when in the 2'nd half of the 20'th century the rest of tye world was building their infrastructure from scratch (so no legacy whatsoever), what do you thing is better course of action for them: Using standard which is dragging a lot of bad decissions from more than a century ago in it increasing its cost and complexity, or use standards that are way more advanced, without all that legacy burden on them?

Then when there was already the 230V, it is obvious they will go for the lighting style optimized for that 230V supply...

I wouldn't go so far as to say the US system is inferior, just different. Besides, everybody knows the British system is best   

I wouldn't go so far as to say the US system is inferior, just different. Besides, everybody knows the British system is best   

Saying a 100 year older system is inferior in few aspects is to me no shame for the authors of that system at all, even when those aspect are very limitting.
It is way older, the first wide spread standard in service, so its creators had to invent everything from scratch, had nowhere to learn. They were great and very smart engineers, doi g thebest job they could do at the time, but they obviously just weren't gods. And unless being gods, I can not imagine how they could know about all the details of their choices that become problems 100 years after they had to make them.

On the contrary, it would be huge shame for a new system, created 100 years later, when there is 100 years of usage experience, for areas with no legacy compatibility burden, to not learn the lessons, address all the known weaknesses and so become significantly better standard.

And regarding British standards: These are dragging a lot of decissions that come up as unfortunate from the past too (big plugs, because the need of the fuse and that because of the 63A ring circuits from the past; instead of the B16 branches designed to protect the appliance cords as well).

And regarding British standards: These are dragging a lot of decissions that come up as unfortunate from the past too (big plugs, because the need of the fuse and that because of the 63A ring circuits from the past; instead of the B16 branches designed to protect the appliance cords as well).

30A was the original rating for ring circuits with rewireable fuses, later changed to 32A when breakers came in. Although now you'll find very few electricians in the UK actually installing rings any more; they're still permitted, but 20A radials are fast becoming the norm.

As for the plugs, they are, to me, simply the best, especially the MK design which even James says he likes, I'm sure he won't mind me quoting him from that thread:

When I used to live in Britain these were the only plugs I would use, I do agree they are the best and superbly made. Very difficult to wire one up dangerously, or for the cable contacts to deteriorate over time even with heavy use.

The fuse in the plug is to me a plus point; even if the circuit doesn't require it strictly speaking, I think it is useful to be able to have one there to protect a lamp or other appliance that may not have an internally fitted fuse. I also like it that the cable enters at the bottom, it is not possible (at least not easily) to pull a plug out by the cable.

30A was the original rating for ring circuits with rewireable fuses, later changed to 32A when breakers came in. Although now you'll find very few electricians in the UK actually installing rings any more; they're still permitted, but 20A radials are fast becoming the norm.

As for the plugs, they are, to me, simply the best, especially the MK design which even James says he likes, I'm sure he won't mind me quoting him from that thread:
The fuse in the plug is to me a plus point; even if the circuit doesn't require it strictly speaking, I think it is useful to be able to have one there to protect a lamp or other appliance that may not have an internally fitted fuse. I also like it that the cable enters at the bottom, it is not possible (at least not easily) to pull a plug out by the cable.

I´m not an expert don british installations, however i think that the 13a, 5a and 3a fuse in the Britisch plug is very important, as it brought adequate protection to the cabel to the electric appliance, especially in the time of ring mains. This is also the car efor 16 and 20A radials, as most flex cords on apllieneces that might malfunction are not rated for this current ond so would need down fusing or the whirring on an 13A MCB (Wich does exist)

Admit, I was not sure about the exact ring circuit rating, but the 30A is still too much for practical appliance cords to handle, mainly in case of short circuit within the appliance. Therefore the fuse in the plug is a must. The advantage is the ability of one circuit to handle multiple large loads. It was created to support multiple rather high power portable heaters (in the 1..2kW range), which seemed to become popular in the UK around (or past) the WW2, until the fire risk inherent for these heaters (when they tip over,...) makes them to disappear from use (the way safer fixed installation models had replaced them).

But the rest of the world goes from other direction: Practical cords are in the 0.5..1.5mm^2 range. The 1.5mm^2 can handle (on free air) 16A load, followed by a short circuit event, so if the maximum breaker in the panel for that branch would be specified to 16A, you don't need any other protection and it is protected against bot overload and short circuit.
The thinner wires (down to 0.75mm^2 is common, theoretically down to 0.5mm^2 at least in 230V areas) could handle the short circuit event, but only if they are not preheated by a high steady load, so the appliance should be designed so it is physically impossible for them to overload the cable for longer time. So e.g. lightbulbs can not draw more than their rating without failing open circuit causing rather hard short circuit within few seconds (if a section of the filament shorts out, the rest blows within a short while, either remaining open or causing a flash over), so a desk lamp can use the cheap 0.75mm^2 cord.
Thinner cords would be theoretically possible, but they become too mechanically fragile so are not used that often, regardless of the current.

Only the 120V areas have a problem (mainly on thinner wire cords), when the wire insulation breaks so the wires are just touching lightly, so it starts arcing but does not cause hard short circuit. Because of the arc drop, with the thinner cord the resulting current may be insufficient to trip the 16A breaker in time, so need extra protection device for this condition (the AFCI).
On 230V the problem is practically nonexistent, as the 230V has high enough voltage margin, so once it barely touches, it instantly forms fat, highly conductive arc, with currents still way sufficient to trip the breaker's fast "short circuit" trigger.

As for the plugs, they are, to me, simply the best

They remind a bit of these weird Czech plugs with that protruding tack in the sockets. Has nobody told them that Schuko rulez?!

Well, whatever the sockets may look: What, at least to my knowledge, is really unknown in the whole of Europe is a mess of medium voltage lines everywhere, with countless pole transformers. Already the look alone... And all these insulated power grids...

By the way, in what was then the GDR the upgrade of 110 V distribution networks to 220 V took until after 1970. It's a pretty interesting topic about which almost nothing can be found online.

They remind a bit of these weird Czech plugs with that protruding tack in the sockets. Has nobody told them that Schuko rulez?!

The problem with Schuko plugs, as with many plugs around the world, is that they are reversible. Polarity isn't always important, but sometimes it is, particularly if getting it wrong can put an appliance switch in the neutral leg or make the shell of a screw cap lampholder live

The problem with Schuko plugs, as with many plugs around the world, is that they are reversible. Polarity isn't always important, but sometimes it is, particularly if getting it wrong can put an appliance switch in the neutral leg or make the shell of a screw cap lampholder live

Appliance switch in the Neutral is not problem, when the appliance is designed for that properly. Practically all more complex appliances (where the power disconnection by that switch is useful for troubleshooting) therefore use 2 pole switch. Only very simple one (like a light,...) use single pole. But that is then meant just as a function control mechanism and not really power switch, safety wise such simple appliance is considered "powered without a switch".
By the way practically all the plug-in timer or thermostat control switches (those which have socket on one side, plug on the back and the switching mechanism between) are switching just the side which is preferred as Neutral. The reason is to ensure the load side always shows as "energized" when controlled by the voltage checkers, as the switch may turn ON any time on its own, so may become hazard for someone thinking something is not powered.

And the lampholder shell may be on the phase and it is not a problem: Unlike the US standards, the shell could be connected only when it is within the socket far enough so you can not touch it. As far as I know, sockets not meeting that requirement are illegal (in consumer products) in whole Europe (and interestingly even in Canada in applications where the Neutral connection of the shell can not be guaranteed).
Although the "strange Czech plug" (used as well at least in Fr, Be, N, except former GDR the whole former eastern bloc; otherwise I knew it as an ABB and actually coming from France... :-) ) can be inserted only in one way,  the Code explicitly makes does not differentiate which side is Phase and which Neutral, both are just referred as "working conductors" and are required to be treated equally.

I don't think relying on the Neutral connection is any good idea: Because when that connection breaks, part of the circuit can easily have live phase voltage on it, yet it should not become dangerous.
On the contrary, the ability to isolate a faulty circuit behind a common RCD requires breakers interrupting the N as well (it became mandatory this or last year in new installations; otherwise a single fault to PE would prevent to reset that RCD even when the breaker to the faulty branch would be off). And with these the zero (or just small) voltage on Neutral can not be guaranteed at all.

I think a lot of the reason for the international adoption of European-spec lighting (and electrical) equipment simply has to do with the strategy of the International General Electric Company of New York (IGE), during the period 1900-1940.  That is a company which is probably not known to many people, but it was the vehicle of GE's Gerard Swope to dominate the entire global electrical industry (at least financially, although as it turned out not in terms of product spec).  For political reasons much of the history of that company has been covered up, but anyone wishing to understand this fascinating situation should read the older books like "Swope of GE" by Loth, or "Anatomy of a Merger" by Jones & Marriott which considers the impact of Swope's strategies from the British and European perspectives.

Most of the principal lighting inventions actually emerged from the USA, and north America also had the richest markets.  The companies in those countries had a truly vast and rich home market - and for many decades simply serving that was their main activity.  The foreign electrical industries at the time were not nearly so large or profitable as USA and Canada, and almost the only strategy of the north American companies was to protect their home markets from invasion by cheap imported products.  This was very successfully achieved by a combination of cartel and patent restrictions.  Of course, the USA companies also wanted to profit from the growing overseas markets, but rather than develop those markets themselves they chose to do it by the easier method of controlling the overseas companies.  Not only did IGE earn a royalty on practically every lamp sold outside the Americas by licensing its patents internationally, it also took major shareholdings in the foreign companies so that it would profit for a second time as those companies grew.  For instance until not so long ago both Osram and Philips were majority-owned by IGE - but they did not interfere so much in the day-to-day running of those companies.

Meanwhile, the European situation was much more fragmented with hundreds of small lighting companies all competing with each other for market share - and often competing over and over again as they annihilated each other during two world wars.  Nearly all of those European companies were licensees of IGE's patents, and IGE dictated how many lamps each company was permitted to manufacture each year (in terms of % market share of the countries where they sold).  If a manufacturer tried to grow, IGE levied hefty fines on them for producing too many lamps, and upsetting the balance of power within the cartel.  Similar fines were levied for trying to produce lamps that were better than competitors, which might risk that end customers would favour one brand over another.  The only way a company could grow its market share was to become rich enough to buy out a competitor, or to develop a new market.

From an early stage, the British lampmakers as well as the European Philips and Osram all figured out that a quicker way to grow was not to fight the other licensed competitors on their home turf, but to search for countries around the world that did not have such strong local lighting manufacturers, and to set up their own satellite operations there and use their technical expertise to dominate those new markets.  If you look at where GE, Westinghouse and Sylvania produced their lamps, the vast majority are from north American factories.  However if you look at where the British and European companies produced lamps, the majority are not in their home markets of Europe, but above all in the Latin American, African, Indian, Asian and other Eastern lands.  Naturally when the European companies built factories in those countries, they produced EU-spec products because that was all they knew - since IGE blocked them from exporting any lamps into the highly protected North American territories.  As a result a situation developed very early in the electric lighting industry that North America went one way, Europe went another way, and the rest of the world followed the European trends.  This wasn't really a problem to IGE because so long as it maintained the stability of its cartel and the international patent agreements, because it profited equally whatever was sold and whoever sold it.

After WW2 and the Sherman Antitrust acts, IGE's dominance of the global electrical industry came under the political spotlight - especially the lamp industry, because that was generating inordinately huge profits far greater than the total of all other electrical industries combined.  Most countries around the world took the view that GE had acted illegally when judged according to how modern postwar laws were emerging, and required IGE to gradually decrease its shareholding and control over the foreign companies during a long period stretching up to around the middle of the 1960s.  Only after this date did the American lighting companies start to realise that they would have to find other ways to continue to earn an income from lighting businesses outside North America, and to try to establish an overseas business along the lines of what is more acceptable these days.  However by then, the former activity of the European and British companies had already set the trends in much of the rest of the world, and that is one of the main reasons why those countries continue to rely on mainly European-spec lighting equipment.

@ Medved - Sorry, you are never going to convince me that polarity is unimportant. It is to me, and that's all I'm going to say on the subject.

I think a lot of the reason for the international adoption of European-spec lighting (and electrical) equipment simply has to do with the strategy of the International General Electric Company of New York (IGE), during the period 1900-1940.  That is a company which is probably not known to many people, but it was the vehicle of GE's Gerard Swope to dominate the entire global electrical industry (at least financially, although as it turned out not in terms of product spec).  For political reasons much of the history of that company has been covered up, but anyone wishing to understand this fascinating situation should read the older books like "Swope of GE" by Loth, or "Anatomy of a Merger" by Jones & Marriott which considers the impact of Swope's strategies from the British and European perspectives.

Most of the principal lighting inventions actually emerged from the USA, and north America also had the richest markets.  The companies in those countries had a truly vast and rich home market - and for many decades simply serving that was their main activity.  The foreign electrical industries at the time were not nearly so large or profitable as USA and Canada, and almost the only strategy of the north American companies was to protect their home markets from invasion by cheap imported products.  This was very successfully achieved by a combination of cartel and patent restrictions.  Of course, the USA companies also wanted to profit from the growing overseas markets, but rather than develop those markets themselves they chose to do it by the easier method of controlling the overseas companies.  Not only did IGE earn a royalty on practically every lamp sold outside the Americas by licensing its patents internationally, it also took major shareholdings in the foreign companies so that it would profit for a second time as those companies grew.  For instance until not so long ago both Osram and Philips were majority-owned by IGE - but they did not interfere so much in the day-to-day running of those companies.

Meanwhile, the European situation was much more fragmented with hundreds of small lighting companies all competing with each other for market share - and often competing over and over again as they annihilated each other during two world wars.  Nearly all of those European companies were licensees of IGE's patents, and IGE dictated how many lamps each company was permitted to manufacture each year (in terms of % market share of the countries where they sold).  If a manufacturer tried to grow, IGE levied hefty fines on them for producing too many lamps, and upsetting the balance of power within the cartel.  Similar fines were levied for trying to produce lamps that were better than competitors, which might risk that end customers would favour one brand over another.  The only way a company could grow its market share was to become rich enough to buy out a competitor, or to develop a new market.

From an early stage, the British lampmakers as well as the European Philips and Osram all figured out that a quicker way to grow was not to fight the other licensed competitors on their home turf, but to search for countries around the world that did not have such strong local lighting manufacturers, and to set up their own satellite operations there and use their technical expertise to dominate those new markets.  If you look at where GE, Westinghouse and Sylvania produced their lamps, the vast majority are from north American factories.  However if you look at where the British and European companies produced lamps, the majority are not in their home markets of Europe, but above all in the Latin American, African, Indian, Asian and other Eastern lands.  Naturally when the European companies built factories in those countries, they produced EU-spec products because that was all they knew - since IGE blocked them from exporting any lamps into the highly protected North American territories.  As a result a situation developed very early in the electric lighting industry that North America went one way, Europe went another way, and the rest of the world followed the European trends.  This wasn't really a problem to IGE because so long as it maintained the stability of its cartel and the international patent agreements, because it profited equally whatever was sold and whoever sold it.

After WW2 and the Sherman Antitrust acts, IGE's dominance of the global electrical industry came under the political spotlight - especially the lamp industry, because that was generating inordinately huge profits far greater than the total of all other electrical industries combined.  Most countries around the world took the view that GE had acted illegally when judged according to how modern postwar laws were emerging, and required IGE to gradually decrease its shareholding and control over the foreign companies during a long period stretching up to around the middle of the 1960s.  Only after this date did the American lighting companies start to realise that they would have to find other ways to continue to earn an income from lighting businesses outside North America, and to try to establish an overseas business along the lines of what is more acceptable these days.  However by then, the former activity of the European and British companies had already set the trends in much of the rest of the world, and that is one of the main reasons why those countries continue to rely on mainly European-spec lighting equipment.

For some reason, I have noticed that some Latin American countries such as Mexico, Colombia, and Venezuela use North American specification lighting with a little bit of European specification lighting while others such as Brazil, Chile, and Argentina mostly use European specification lighting. I also wonder why some Latin American countries chose to use North American specification lighting while others chose to use European specification lighting.