History of the Italian electrical system

The Italian electrical system has a fairly complicated history; from different voltages and frequencies to the type of plugs used, almost everything about it has changed over the last century, or is in the process of changing.

While nowadays it's well known that North America uses 120V and Europe (as well as most other places) use 230V, this wasn't the case - for decades parts of Europe, such as Italy, also used 120V, either entirely or only for certain applications, and switched voltages later on.

This page documents this history, specifically regarding the situation in Italy, and the various changes that happened over time as the electrical system evolved.

The beginning

As with most countries, electrical supplies in the early days of electrification were divided between different regions and even across cities, as grids were owned by many small regional power companies; thus, voltages and frequencies (42Hz was quite common) could vary a lot between each other.

This is made quite evident on this list, taken from the Italian Wikipedia page about electrical distribution, which shows the various voltages in use in major urban centres in Italy back in the day. Note that some cities are listed twice - this was because of multiple companies operating in the same cities, each with their own type of supply.

Later on the smaller companies were acquired by larger ones, and in the 60s a national electric company - ENEL - was formed. Part of their goal was to unify the various supplies, and move to a unified standard. However, one thing remained for a few more decades...

The dual tariff system

During this time, electricity was mainly used for lighting, and later on also simple devices such as fans and radios. If you wanted to use any appliances you had to pay for a higher rate of electricity, which was metered and taxed differently - the idea was, that if you were rich enough to own, for example, a washing machine (which was very expensive at the time), you definitely had enough money to pay for the appliances supply.

To prevent people from using the cheaper lighting supply for appliances, this was powered at a different voltage - for example, 120 or 150V - and often was also limited to only a few kilowatts. Appliances, on the other hand, used a higher voltage, generally 220V (though 260V was also a thing), which also helped with efficiency.

As a result of this, some electrical devices made back then aren't usable now without a transformer to step down the voltage - this is quite common on smaller tube radios and fans which were meant to be used with the lighting supply. Other devices, instead, had voltage selector taps on the back - some of these were for 120/150V-only, but often these also included an option for 220V (for tube radios, this was generally the case for ones with a built-in transformer), which makes it possible to use them even today.

How these supplies worked

The way this worked was quite simple: 127/220V three-phase transformers were common, which provided 120V between one of the phases and neutral, for the lighting supplies, and 220V between phases for the appliances supply. So, if you only needed to power lights, you received a single phase and a neutral, while if you also had an appliances supply you had two phases (or three phases for industrial applications) and a neutral, and two separate power meters.

This arrangement is somewhat similar to the electrical supplies used in North America nowadays, where 120V is used for most appliances and 240 or 208V is used for heavy appliances, though one major difference is that split phase was very uncommon here.

Two types of plug

Because of these dual supplies, and the two voltages they used, two different types of plug became common, and are nowadays both known as type L: a "small" 10A one meant for the lighting supply, and thus generally used for 120V, and a "big" 16A one meant for appliances, and thus generally used for 220V.

"Big" sockets were incompatible with "small" plugs and viceversa, a useful feature to prevent breaking your precious electrical appliances.

Moving to 220V

Over time, as electricity became common, more and more people bought electrical appliances and thus most houses had two power meters and both 120 and 220V sockets in their home. As time moved on, 220V became used for more and more things, and people began wiring up 10A socket for use on 220V (which lead to some interesting results when a 120V devices was plugged to a 220V socket); as such, the whole structure of "small" sockets being for 120V and "big" ones being for 220V slowly began to fall.

Additionally, even lighting supplies began getting migrated to 220V - at that point lighting was mostly the only thing a house would have used 120V for - but, even after the migration, dual metering continued to exist for a while longer. Even by the mid-70s 120V supplies were still in use, necessitating two meters, and houses with 220V only could either have one or two meters.

Because of these dual supplies, and the two voltages they used, two different types of plug became common, and are During this time adaptors to go between the two different types of socket became common, and the purposeful lack of intercompatibility between the two went from a useful feature to a growing problem, especially as single-meter 220V supplies became more common.

On these installations, 10A sockets were often also used on the same exact circuits as 16A ones, making the separation even more pointless. A solution to this came in the form of the Bipasso sockets, 16A sockets which also accepted 10A plugs. These became more common for new installations, starting in the 70s-80s, solving the compatibility problem.

The legacy

Nowadays 120V supplies are no longer a thing - the last one was shut down in Lazio in 1999, thus marking the end of that era, though by then they had become extremely rare already. However, certain elements of that legacy still remain: the most notable part is the use of the two type L plugs, as well as Schuko ones.

Additionally, some areas still use the old 127/220V transformers; houses in these areas receive two phases, both live at 127V with respect to earth. Special care must be taken in buildings fed by those transformers, to make sure proper double-pole (2P) breakers are used, to avoid things remaining live accidentally.

Unfortunately, some electric car chargers don't like this sort of supply, and will outright refuse to work on it. This is apparently a somewhat common problem in parts of Rome, where not all "dual phase" transformers have been replaced yet. Thankfully, in general, these supplies are quite uncommon in Italy, and will get rarer and rarer as remaining ones get phased out as transformers get upgraded.