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@alan 279 I believe main distribution networks now are all 3 phase, to deliver sufficient power to a neighbourhood. Back in the day, lots of houses used 3 phase, as a back up to one phase failing...! But it is more expensive, and not necessary today outside of commercial uses. To come to your house you will need 4 cables - 3 phases and a common or neutral... And, of course, you must have an earth or ground circuit everywhere, as each phase can typically deliver up to 110 amps... enough to kill you easily!!

@alan279

7 August 2025

If there are 3 lines, it is most likely a 2 phase (110V each) and a neutral.  The voltage difference between the 2 - 110V phases is what generates the single phase 220V.  If you want to get a 2 phase - 110V, you will have to use the neutral line.  One phase will be from one 110V live and the neutral and the second phase will be from the second 110V live and the neutral.   This is how the power is distributed in the US.

Of course, you should also provide a very reliable ground for safety as peter_itamaraca mentioned.

I would be more worried about the power supply amperage to the house.  An estimate of what 50kW charger would need is at least a 100A per phase supply.  This is also dependent on the Power Factor of the supply too...

I would definitely hire an expert who will handle the grounding, subpanel installation, circuit breakers, etc. and permits.

@Peter Itamaraca

I have a new green (color) transformer in front of my apartment from four years ago.

There are three overhead wires on the street. The transformer has three inputs and three outputs. I have 127v and 220v outlets in my apartment.

@Pablo888

We have 127v and 220v power to houses here.

@alan279

And I can't send you a photo on this platform.

@Pablo888

I have two engineering degrees and I never do DIY electrical work. 😀

Can I install a 50 kw DC fast charger that requires 3 phase power to charge my friends' electric cars? - @alan279

I conclusion, I think it it will be prohibitively expensive to install this into your domestic situation - both in terms of equipment required and cost to install, let alone the actual power costs to use it on a number of cars. It is only really suitable for commercial premises, where a charge may be levied, and multiple users are likely to be found.

@Peter Itamaraca

It would be a commercial venture (boondoggle?). A 50kw charger costs R$100.000.

@Peter Itamaraca

If electrical power distribution is Brazil is three phase as in my neighborhood, is 50kw available on every street in my neighborhood? The transformers all look the same, though they can be closer together for commercial buildings

@alan279

It is difficult to comment on one neighbourhood that I do not know, when there are so many variances all over Brazil...! I do not know what the rating is for your transformers, but it does make sense they will all be rated the same...

@alan279
It is difficult to comment on one neighbourhood that I do not know, when there are so many variances all over Brazil...! I do not know what the rating is for your transformers, but it does make sense they will all be rated the same... - @Peter Itamaraca

9 August 2025

@alan279, if the first name of your friend is Elon, I would say that yes, please invest in the charger and spend even more to solve all 3 phase power issues of Brasil.  If it is THE person, he has $Billions to spend...