Really all modern residential connections in Europe are 400V three phase electric power, capable to immediately power an electric motor without the need of capacitors.
No matter how you put it, the US residential power grid is conceptionally lagging.
For example, a common big motor that needs a starter capacitor is a HVAC unit. Usually the copper to run those is extremely expensive, on the order of hundreds of dollars. Adding an additional wire may add an additional hundred dollars or more. By comparison, starter caps are quite cheap. $20 for a HVAC sized one. That also isn't counting any of the costs of three phase infrastructure for breakers etc.
That also isn't even counting that many appliances are moving to inverter based technologies that don't utilize induction motors at all, such as induction hobs. Or, many appliances with no benefit from extra phases (resistive heating devices such as ovens, dryers, toasters, etc).
Seems to me that the tradeoff is worth it.
However, for low capacity hops the cost of additional insulation and extra copper needed to achieve ampacity (for worst case fault currents-- the cable must have higher capacity than the breaker so the breaker trips first and with 3ph you have three over-provisioned conductors instead of two) may make it worse off.
Even if an extra conductor in the line was a few hundred dollars, I’d rather have one less common failure point. In AZ AC is effectively required in the summer. AC outages are similar to winter furnace outages in northern areas. I have extra caps ready to deploy (we lose a cap about every 3 years across multiple units) but have never needed to unexpectedly replace copper.
The fact that they might have a higher list price than a conventional single-speed outdoor unit and indoor evaporator coil is a red herring, as the conventional units can’t do anything on their own, and they need a furnace and a fan added to be useful.
I agree that less failure points is nice, however you have to consider the tradeoff. Is it worth $100? Probably. What about $1000? $2000? If it's $2000, why not just get a more efficient inverter based one, which doesn't have a starter cap in the first place?
Split-phase system and 110V are currently more expensive in term of infrastructure.
The distribution itself is done in 3-phases power, even in the US. The conversion to 110V and split phase is done in the last mile as close as possible to the termination point to limit losses. You have to have tiny power transformers everywhere and this has a significant cost.
At the opposite, end-to-end 400V three phases system requires to have only one large transformer by Area. Generally directly connected to High Voltage (20KV in Europe).
Standalone houses usually have multiple houses connected to one single transformer. How much depends on density of the houses. For apartment buildings and other dense power needs, there's high voltage directly into the complex, then it's stepped down within the complex to meet the needs.
Instead of those little pole-mounted transformers that are common in the US, we have one of these buildings with a large transformer for each neighborhood https://dms-cf-08.dimu.org/image/032ykUus1ixX?dimension=1200...
https://electrical-engineering-portal.com/north-american-ver...
They do currently.
I can at talk for the French and Swiss system.
- Entire neighbourhood are served by a single 400V 3-phase transformer.
- For critical infrastructure, you do have sometimes two transformers in redundancy on the same local loop in case of failure on one.
There is no need for the pole type of transformer everywhere in the street with double layers of cable like in Japan or in the US.
You might find that interesting:
https://data.enedis.fr/pages/cartographie-des-reseaux-conten...
This map references all transformers and distribution lines for the french network nationwide for terminal loops. These are open data: Enedis is a the public operator.
"Poste" is the French Jargon for transformer. BT is for low voltage. HT is for anything >1000V.
Like you will see yourself, the density of transformer is of the order of 10x less than in the US/Japanese model.
Example of appliances: HVAC, induction heaters, boilers, car chargers, solar panels inverters, ...
I know of at least one, but I am ignorant of many other things and this just comes from my understanding of AC motors but: Any directly connected AC fan will have enormous benefits in terms of performance and efficiency with three phase.
Controlling the motor with a VFD is how you increase the efficiency and performance of a three-phase motor, simply being a three-phase motor provides no efficiency benefit other than you can use slightly smaller conductors to power the motor.
The problem is getting the motor to start spinning. You cant start all motors on just one or two phases. And if a motor isn't spinning, it's essentially a short.
Three phase wiring is so ubiquitous here, there is nearly no additional cost.
It may be offset, as others point out, by power delivered being higher (and thus, wire gauge can go down) when running 3 phase... however that will largely depend on the load.
I have monitoring on all the phases on my house (in Sweden) and I can charge two electric cars, run the heating in winter, run the washer and drier and cook with two ovens a microwave and the induction hob at the same time and everything just works.
Things on three phase in my home: swimming pool, sauna, induction hob, electric car chargers, heating system and I have sockets to plug-in welding and other power hungry equipment. The rest is split on the phases. I can’t remember whether my solar system supplies on three phases or not but I think it does.
Yes, we have it so we use it - for sure.
The pool pump on 3 phases seems slightly more efficient when I compared them last time. The pool is also being fitted with a heat pump inverter, which doesn’t need 3 phase.
That can easily support all the things you listed and do it for a 2500 sq ft house, based on the overly conservative and outdated US NEC lead calculations.
Vs. checking a couple commodity pricing web sites - copper is currently ~$3.85 per pound.
I really doubt the motor of any "residential" HVAC unit is heavy enough for that "hundreds of dollars" to actually pan out...
To note, as mentioned, copper is not the only cost here. You also need another pole to your breaker, which adds cost. Plus busbar upgrades. And more.
The cost of termination of 3 phases is insignificant compared to the cost of the rest of an electrical system in a modern home.
It’s the better system.
What's the deal with your electric showers anyway? Surely it's more efficient to heat in a central location and distribute both a cold and a hot water circuit through the building...
Probably talking out of my ass, it's just so weird and I haven't seen it anywhere other than in the UK.
On-demand heating has the advantage that there is no thermal loss due to keeping a large amount of water (plus piping) hot 24 hrs a day.
Plus water is not wasted in waiting for hot water to arrive each time a tap is switched on.
Back in the days of Coal-fired power stations, people were encouraged to use storage hot water systems which were automatically switched on at night, so the the power stations could continue running because of the large base-load power demand.
However the modern Solar/wind generated power systems are the opposite, they much prefer loads which are only on during the daytime.
Regarding solar HWS: The cost of heating panels, piping, and installation, has meant that they are fast disappearing from the market. It's better to add a few extra solar electric panels and use on-demand HWS, either with battery storage or via grid connect.
I've just been down this route with a new solar electric plant. I had originally assumed that Solar HWS would be included, but after doing the calcs, have abandoned the solar heating panels and instead opted for a few more solar electric panels plus extra Lithium batteries. It means I have a lot more storage that can used for many different purposes.
Heat pump heater can be run when solar panel generates so much energy (energy price is low). That's a similar thing as batteries for energy use time shift.
I've seen them (my parents have one) in the UK, and lower income countries in South America, Asia and Africa.
You are very luky! The standard installed power for residential use in Italy is 220 V, 3.3 kW.
Said 50m² apartment has 16A triple-phase installed, but the breaker box is wired to be capable of safely drawing up to 63A triple-phase from the grid if I needed it.
This results in a big payoff for efficiency, however: high efficiency AC and heat pumps for water go a long way in increasing how much you can do on so much little power.
Jokes aside, I think that this ends up incentivizing an efficient use of energy. That's not so bad after all.
Induction hobs, saunas, EV chargers, to name some.
> and is the benefit outweighed by the additional cost of more copper for the additional wires?
Additional cost? You don't run that many 3-phase circuits, so the cost is negligible, and your 110V circuits require substantially higher current than ours (meaning thicker wires) so if anything I'd guess the cost for wiring a US home is on average higher than a European home.
You can add: Heat pump, electrical water heater, well pump, ovens.
I lived in both Europe (400V) and Japan (100V).
In Europe I do have an EV charging station 3-phase power with 22KW capacity at home. It does not requires anything special in term of cabling.
And it is enough to reload a Tesla in 4-5 hours, it makes EV ownership a lot easier.
Doing that with the 100V power-grid Japan is simply impossible. Most grid operator will refuse to connect 3 phases power to individuals.
Modern heat pumps in Japan with inverter is just fine with 100V or 200V for home, even for cheaper coolers. 200V hear pump electrical water heater (with tank) too.
Most houses sign up only up to 6kW or 10kW electricity, so EV charger will become a problem for family that has multiple EVs, but they will be fine with slower charging at night in most cases.
It's pain that common 100V ovens works poorly. 100V Washer dryer works barely okay thanks to efficiency. I want more 200V home appliances, like 200V 3kW kettle!
Obviously 100V would be terrible for high power stuff. I'm not suggesting that. But, 240V split-phase is more than sufficient for the vast majority of residential appliances, including EV charging.
They do too. You have lower current intensity, lower cable diameter, lower losses.
For EV charger it is even more relevant because anything inverter based has (theorically) a better efficiency in a three phases system.
The only drawback of three phase power is currently the cabling complexity. The home electrical panel need to be careful of the phases's balance.
Regarding EVs... I would assume that depends on the design. No EV sold in north america is even capable of being charged off 3-phase AC anyways, so it would require quite the redesign.
don’t cheap out on wiring. a few years after you move homes, you find some new hobby: woodworking, CNC or 3d printing, restoring pinball/arcade machines, HiFi audio, hosting LAN parties or just a few beefy gaming or video editing rigs, hot tubs, _whatever_. you can’t predict it, but there’s a good chance it’ll need power, and once you pass 1500 W in one area of the home you’re gonna either be playing the “semi-permanent 50-ft extension cords bridging the under-utilized circuits to the over-utilized rooms” (and shuffling those around with every spring cleaning) or paying 4 figures to rip out the drywall and rewire shit. just pay that up front: it’s not worth the hassle and if you have a decent realtor you’ll recoup the bulk of the investment come sale time.
due to the higher voltage in europe, conductors tend to be quite a bit thinner than in the US, to carry the same amount of energy. That being said, our electrical installations tend to be much beefier than most US residential, so a lot of copper is used. in Denmark for example standard for houses is to be fused at the roadside box for 3x~30A
Overall, it can heat things up more quickly than a typical gas or electric stove while being more efficient. And you can quickly change the temperature like with a gas stove.
It is entirely possible to get three phase, high-voltage power in North America, it just isn't run to individual houses unless specifically requested.
Even apartments have that full 3-phases, but just for plugging in the oven and the sauna stove.
The US grid is basically 3-phase everywhere, but it's neither needed nor cost-effective to run it into the home.
Now, the 400V part is different. That would require less copper (but with a safety cost).
400V between phases so 230V per phase. Safety is provided by making plugs not expose contacts while half plugged. US plugs are really unsafe compared to plugs used in most of the Europe.
If you want to run a machine shop, it’s a pain but not impossible to get 440 three phase wired straight through to your business. But consumer “heavy” motors and induction stoves run on two phase 230V.
Anything high power, you go for this plug. I'd imagine car charging would also benefit from this but not personally in that market yet.
Plugs are usually Shuko for high power appliances (washing machine) and two smaller pins for low power (phone chargers.)
By the way, Italy traditionally had a three pin in a line high power plug but more and more appliances are coming with Shuko plugs so wall socket are either bi-standard or just Shuko now.
Btw, Europe standardized at 230/400V in the nineties. In Czechia we switched from 220V to 230V in 1993. Not sure when Italy did, but probably around the same time.
Is this sort of use common in Finland? It seems like kinda a waste of money and materials to install the infrastructure to allow everyone to run heavy construction equipment off their home's electrical supply.
In the US, a developer typically buys an entire neighborhood's worth of land and builds a bunch of houses there to sell to individuals.
Over here, the individuals will typically buy their own small plot of land and then have a house built there according to their specifications. You need to be able to run heavy construction equipment to do so.
This shows a 32A 400V socket costs under 10 euros: https://www.taloon.com/voimapistorasia-pinta-bals-101-3pne-3...
The split phase is two lives, neutral and ground. 3-phase is 3 lives, neutral and ground.
Pretty sure that’s standard for the UK
I reported it and it was sorted pretty quickly.
Larger users are presumably connected with three phases by default — that primary school in the middle of the housing estate, the retirement home that has several lifts, not-tiny shops, the small block of flats etc.
That said, a few cities/states don't allow 3 phase to residences in their building code. However most do allow it, and so it is just a matter of convincing the power company to run it.
It's nice because there's no motor to worry about maintaining and the machines can run at full power.
That said you just pay that once, after that you have your rate.
A lot of people have odd power requirements - but usually not residences. Farms typically get 400V for greenhouse fans, for example.
Seems the power grid has the capability of delivering three phase power, but many (most?) homes in quite a few European countries don't actually have all three phases delivered.
> No matter how you put it, the US residential power grid is conceptionally lagging.
That's only the case if you believe the US is "missing out" on all that much with our split-phase setup. I don't think that's the case, really. Even for EV charging, using the 240V across the -120V and 120V lines is more or less fine. We've been doing the same thing with our electric stoves, water heaters, etc. for quite some time now.
Certainly there are some things you can do with 3-phase that aren't really feasible with split-phase, but I don't think most people living in the US care too much. It's true that those who do are probably upset about it, though!
Also consider that the US power system is trivially 3-phase! We just don't wire all those phases to homes, as we a) don't generally see the need to, b) chicken-and-egg problem suggests that most people wouldn't be able to use it anyway, since appliances made for the US wouldn't be able to take advantage of it.
[0] https://electronics.stackexchange.com/questions/625353/is-3-...
It was also free (there was a small cost, but the government subsidizes it to encourage that people switch to heat pumps).
Split phase is almost always the last mile to residential customers as it’s simpler and easier to reason about (less likely to have severely unbalanced phases too) and requires fewer conductors.
Seems the power grid has the capability of delivering three phase power, but many (most?) homes in quite a few European countries don't actually have all three phases delivered.
—-
Really all modern residential connections in Europe are 400V three phase electric power
You see if they don’t have it delivered, it’s not a modern connection. Conundrum solved!
One of my favorite things about US residential power is that 120v is far less dangerous when homeowners (or worse, kids) accidentally do something they shouldn't.
Most european houses have a single 400v outlet: right in your kitchen, for the oven (which means the oven is going to be right in front of it.) The likelihood of a child playing with it is close to nil. As for adults, the vast majority of people are taught to just flip the breaker and work on it if needed.
I promise you more people died of sticking metal into US outlets than from 400 volts.
Modern US outlets are usually shuttered, and 3 prong grounded outlets have been the required standard since about 1969. Which is over 50 years ago.
Given how many things I have plugged in on or around my desk, I’d need power strips the size of a large dog to plug them all in UK style. Whereas US they all fit in the size of a very small cat.
Also, stepping on one in the dark is a… life changing experience! Definitely pretty solid though.
Literally every single thing you've asserted is categorically false.
Earth pins have been required on outlets for nearly 50 years at this point. US outlets are also polarized, which Europlugs are not.
Shutters on outlets have been mandatory in residences and medical facilities for well over a decade.
The cable gauge is sized for the current and ambient temperature.
GFCI outlets are required nearly everywhere there is water, damp conditions (such as basements), and power tools used (such as garages and outdoors) because tools are most likely to have frayed and poorly repaired cords. Additionally all bedrooms and living spaces now require arc fault protection as a leading cause of fires is due to frayed lamp cords.
Europe still leads the world when it comes to smoking in bed as being a leading cause of house fires so I would not cast stones in glass houses.
The only shutters on outlets in any US homes I've ever lived in have been... ones I put in myself.
Many people don't notice they exist. You have to examine the outlet fairly closely to notice them but certainly any new construction is all TR receptacles now (with the possible exception of the ones very far off the floor).
Also GFCI is very common now. The vast majority of kitchens or bathrooms will have it. You'd need to find one that hasn't been renovated since the 90s, which definitely does happen, but it's becoming less common.
That is why the voltage should be lowered to 70 Volts.
The voltage shouldn't be lowered, the pins should simply be designed not to be both connected and exposed at the same time.
False
> GFCI outlets are a miracle to find
False
I don't know where some of these people come from on hackernews.
Not to mention you normally can not electrocute yourself with 400V.
400V is between two phases, you never accidentally touch two phases.
When you touch a conductor you are between one phase and the ground, meaning in 230V.
-1/2 to 3/4 HP furnace fan - 3 to 5 ton AC unit
Neither of these benefit from a 3-phase motor aside from not having to swap out $10 start/run capacitors, the conductors would be #8 for 3p and #6 for split phase.
You can easily power a three-phase motor on a split-phase service with a VFD.
You can get three-phase power in certain locations at a residence, but you pay a monthly connection charge and commercial rates.
One ton of cooling is defined as 12,000 BTU/hour. The "real" value is 11966; apparently it's coincidental that it is so close to a round number. (One ton of refrigeration is 3517 watts in metric.)
The latent heat of fusion of 1 pound of water at 0°C is 144 BTU. 144 BTU/lb * 2000 lb/ton / 24 hr is 12000 BTU/hr per ton exactly.
And further, I guess there's just not much to be gained by going metric and saying "14 kilowatt AC unit" vs. "4-ton AC unit".
Tons (or, BTUs of cooling) makes more sense, because the efficiency for a given cooling amount is variable.
For efficiency, we have efficiency ratings in the SEER/SEER2 ratings.
Not just conceptually == reliability is lower than that of its peers: https://www.statista.com/statistics/268155/ranking-of-the-20... (if you don't have a statista account, US is at the bottom of this list at 98.6)
State level data: https://www.eia.gov/electricity/data/eia861/
I had to upgrade my electricity meter and switch box (even though as mentioned three-phase to the house is already standard) recently in order to accommodate planned environmental upgrades.
Not the case in the UK.