We take for granted that electrical power standards are generally unified across countries and territories. Europe for instance has a standard at 230 volts AC, with a wide enough voltage acceptance band to accommodate places still running at 220 or 240 volts. Even the sockets maintain a level of compatibility across territories, with a few notable exceptions.
It was not always this way though, and to illustrate this we have [Sam], who’s provided us with a potted history of mains power in Italy. The complex twists and turns of power delivery in that country reflect the diversity of the power industry in the late 19th and early 20th century as the technology spread across the continent.
Starting with a table showing the impressive range of voltages found across the country from differing power countries, it delves into the taxation of power in Italy which led to two entirely different plug standards, and their 110/220 volt system. Nationalization may have ironed out some of the kinks and unified 220 volts across the country, but the two plugs remain.
Altogether it’s a fascinating read, and one which brings to mind that where this is being written you could still find a few years ago some houses with three sizes of the archaic British round-pin socket. Interested in the diversity of plugs? We have a link for that.
Well, that clears up the mystery of the 155VAC setting on the Blaupunkt Granada tube radio my wife owns. Her parents bought it in the 1960s. I’ve always wondered why it had a setting for 155VAC.
The article about the history of AC power in Italy has a table that shows many regions using 150VAC and many regions using 160VAC. 155VAC would let the radio work properly at either voltage.
https://josepheoff.github.io/posts/blaupunkt20300-1
Nominal voltages for AC power are just nominal anyhow. Don’t count on the number. Look up the standard minimum design voltage for each region’s system.
ANSI says the power company is expected to be within 5%, but ANSI also says that equipment should be designed to work +- 10%.
ANSI doesn’t carry much weight in Italy though, fuzzy little foreigners have a different word for _everything_.
How the grid naturally regulates. Most power supplies draw less power when the voltage drops. But switchers will break the system once dominant. They draw more power when the voltage drops. Double plus bad.
Oh, hey, it’s Sam’s site! So much cool stuff on there.
As a kid I was so very upset that my expensive UV fluorescent grow tubes most often would not turn on until i thought to measure the plug voltage …. 190V in the UK !!
Reminds me of a time in my parents’ house when there was a powercut, except… there wasn’t. They have an ancient off peak supply which seemingly is on a different phase, and the off peak was timed from a long forgotten analog or clockwork timer i.e. its off peak was well out of sync with the actual off peak times. This couple with my dad wiring up one socket in the dining room to the wonkey off peak supply.
So, the power went off, except a light plugged into the off peak socket was still on. Then I can’t remember if it was the off peak or main supply (I think the main) but the voltage was at about 80V and fluctuating. A PC with switch-mode PSU however was seemingly happy to sip this unstable 80V and power the PC. But this wasn’t a once off, they had another brown out earlier this year and another PC with appropriately sized (3A I think) fuse in the plug was ready to serve, but the PSU drawing more than triple the usual current thanks to the low voltage blew the fuse.
This could have happened anywhere but I was giving a class in Milan and had provided all of the equipment. The pee cees were all universal or so I thought. So we just got the inexpensive and funny looking plug adaptors for them. I got them all set up, save my server, which thank god was just a higher spec pee cee. I turned that on and the power light flashed a few times and went off. WTF? It probably did not help this was right post a 9 hour flight with no rest. So I hit the button again and it flashed a few times and went out. Ok, I am smarter than a damn pee cee, so I held the button in and the light flashed a few times and went out and a few seconds later a little whisp of smoke came out of the computer. It was then I looked at the back of it and that was an exception to the rule, that one did not have a universal supply. So I was able to trade with another one and verify that I lucked out and it was just the power supply that went up in smoke, and I hooked up with one of my buds in that office to help on the phone and with driving (I am pretty brave, but not brave enough to drive around Milan) and we found this little pee cee shop and he had a universal atx supply, and amazingly, everything came off as planned.
Now that is a story for the Hackaday yarn spinner!
Momma Mia!
Re the driving: we were cocky enough to drive through the streets of Verona and around Milan on the autostrada in our RHD Toyota, and lucky enough that it all worked out. After six years of “other” side of the road driving in Oz and the UK, we were game for anything.
Driving the Periphique round Paris on a motorbike ….. could not find the right exit …. got really tired and ended up camping on the edge of Charles de Gualle airport ….. rude awakening at 6 am with jumbo jet 200 ft above.
Italy and fragmentation, name a more iconic duo. Consequence of being a country freshly created from a bunch of different kingdoms.
Until the spread of TV, even language was different from one area to another, to the point of making communication difficult.
This reminds me of the original “Italian Job” movie where the heros took over the Rome traffic control system, like that could ever happen. Italian standards are suggestions, not rules.
“You were only supposed to blow the bloody doors off!”
Oh well, don’t forget about Bticino Magic:
https://it.wikipedia.org/wiki/BTicino_Magic#/media/File:Bticino_Magic_2.jpg
We in Chile use the italian plug.
I’m fortunate enough to know Sam in real life and he is the nicest and warmest person I’ve ever met. Just the type of man who is so good, he makes you happy to be of the same species.
Doesn’t Japan still have split 50/60Hz regions? AFAIK all of Japan are on 100-ish VAC but the different frequency makes moving equipment challenging.
>Doesn’t Japan still have split 50/60Hz regions?
Yes.
Japan also has 2 prong unearthed plugs, 3 prong earthed plugs, and 2 prong plugs with a seperate, loose earth wire that you attach to a screw terminal on the socket.
So that’s why the Sharp MZ computers have that long grounding screw!
You learn something new every day!
Yes. I have had to design equipment for international use and Japan is definitely and outlier. Lowest “standard” voltage in the world. The reasons for it are complex, but the 60Hz is courtesy of the US after the war, dunno where the 100V comes from but the outlet current rating is lower than “normal” as well, and there appears to be no “high current” supply except on “special order”, so forget about your 240V electric clothes dryer or stove.
“The reasons for it are complex, but the 60Hz is courtesy of the US after the war [..]”
Which proves that not always the best system wins. ;)
Seriously, 50 Hz is (was) better.
For both film to TV conversions (24 fps to 25 fps) and home computers of the 80s.
Because, 50 Hz systems had a higher resolution due to being slower.
Anyway, they later had MUSE, which was better than NTSC/60 Hz, SECAM or PAL.
60 Hz is better for motors and transformers, both were way more relevant than TV and video gaming, back when the standards were set.
I’m italian in his 30’s and now i finally know why some old electric devices i have are rated 110/230, why i have 16A socket only 20cm from the ground ,10A socket 1m higher and bipasso randomly placed here and there instead of a single standard plug.
Now it makes more sense.
Unfortunately the depicted items on the mentioned page aren’t from the years recalled. Three prongs plugs were very rare until the 70s (the pictured ones are just from the 80s); the lower powered devices, like a table lamp, had no earth ground connection, no double insulation requirement – even for an all metal abat-jour, at least with a ceramic insulated bulb socket, but without much protection for fingers to bulb screw.
I can witness of many houses of the 60s without *any* earth ground conductor, that became common only for later larger appliances, like ovens, washers, etc.
I’ve updated myself houses with multi-colored (what standard? None) single strand copper wires, sometimes burned in the walls. Some other times with wires just *nailed* over the walls, with sockets and switches that could have had Edison raise eyebrows. No GFCI, very few fuses, the scarce ground wires bolted to water pipes.
I guess that until the 60s, when the industrial boom changed the country, almost anything was accepted.
By the way, somehow I survived.
So, people from US (where not even the age to drink a beer is standardized) are surprised for the lack of standardization of voltage a century ago?
In a world where the first Mac (unofficially) arrived in Italy was marked 117V which happen in my hands for some reason
In a world where Japan is half 50 and half 60 Hz
In a world where the only country that uses the “standard” UE plugs is Brazil
In a world where British plugs can kill a person (I mean throwing them, not touching live conductors :D )
In a world where the American plugs are universally known as the ugliest electric things ever invented
The surprise comes from Italy.
Ok, took note of that :D
The age to drink beer in the USA remains standardized at 14.
The partly sleeved conductors on the live/neutral pins of the plug and the safety shutter on the socket are a much later addition, I think from the early 80’s. I still have some devices with the older unshielded plugs, and some adapters without the sprung safety shield that can provide nicely exposed conductors for tiny probing fingers…
Speaking of live part protection I’m not sure how many people (even in Italy) are aware of the patent from the Italian Vimar company to protect the Italian wall sockets (then extended to many other national sockets).
https://www.vimar.com/it/it/brevetto-vimar-sicury-bimbi-sicuri-e-brevetto-vimar-bpresa-6020152.html
The news are actually two
1) It works very well
2) It was made free to use to other competing companies for free, and now is widespread around the world.
In a world dominated by patent trolls it’s almost too good to be true, but it is
Still in the 60’s, before Enel (National Electrical System) imposed tech
standards the mains lines voltage swings were severe, and especially
deadly for valve TV sets.
People had to buy special “auto-transformers” to have a decently stable
220 volts and avoid fastidious and expensive troubles