What is the different between American and European electric supply?

[IanB]

In North America we have both 110 and 220, the latter being for larger appliances. So is the American 220 identical to European 220?
This site says no...

Americans who have European equipment should not connect it to these outlets, since the phasing is wrong.

To talk of "European" equipment here is not useful, since Europe has many different electrical standards, varying from country to country.

However, if the equipment concerned operates on a compatible voltage, and if the equipment concerned is not sensitive to the different AC frequency, then you could connect a European device to an American supply.

To take one example, the main difference between an American domestic 240 V supply and a UK 240 V domestic supply is the grounding/earthing arrangement. In the US outlet both legs of the 240 V supply are hot and are 120 V from ground. In the UK 240 V supply one leg is live and one leg is neutral (close to earth potential). In other European countries the supply voltage and grounding arrangements may be different.

As mentioned by other posters, European devices are designed to operate safely in a variety of different supply situations with both supply legs fully isolated and insulated from exposed parts. So a European nominal 230 V device can be plugged into a US 240 V socket without problems.

Personally I trust the design of European appliances more than US appliances. For instance, a stainless steel electric kettle in the UK will have a three pin plug and all exposed metal parts will be bonded to earth at the plug. A stainless steel kettle in the US (along with most other kitchen appliances) will have a two pin plug, a figure 8 zip cord and no grounding. Exposed metal parts are simply floating. I find this unnerving.

[jmelson]

In North America we have both 110 and 220, the latter being for larger appliances. So is the American 220 identical to European 220?
This site says no...

In the US, the typical residential supply is 120 -0-120, ie. a 240 V transformer secondary with a grounded center tap.  So, you will get a nominal 120 V from earth ground to either hot terminal.  Normal residential utility outlets deliver only one of these hot wires, so you get 120 V hot, and a grounded neutral.  This is single-phase power.  Rarely do single family residences have 3-phase power, but it is much more common in apartment buildings to have 3-phase available.  In those cases, you often have a 120-208 V (Wye) system, where any hot to hot wire measures 208 V, while any hot to neutral measures 120 V.

Much of Europe delivers 3-phase power to most residences, and is similar to the US Wye system, except the voltages are 230 V line to neutral, and 400 V line to line.
But, there's LOTS of variations in certain countries.

The US also has some odd systems in older industrial settings, often called open-delta.  One uses one center-tapped residential transformer to give both 230 V 3-phase power AND 120-0-120 single-phase supply for office loads from the same transformers and panel.  That is called center-grounded open-delta.  There is also a system called corner-grounded open-delta, that only gives 230 V 3-phase (or a choice of 230 V single phase loads).  These can be hooked up with 2-pole breaker panels, the same as used in residential service.

Jon

[coppice]

Much of Europe delivers 3-phase power to most residences, and is similar to the US Wye system, except the voltages are 230 V line to neutral, and 400 V line to line.

The only European country where 3 phase for domestic installations is the norm is Germany. Domestic 3 phase exists elsewhere in European, but its not the standard practice. Most streets have 3 phase power, and they spread the phases out across the houses.

[tooki]

In North America we have both 110 and 220, the latter being for larger appliances.

No, we don’t. (I’m American.) We have 120V/240V. It hasn’t been 110/220V for over 70 years.

[Brumby]

Personally I don't understand why countries use 110V. When compared to 240V system, using 110V doubles the current and quadruples power losses for the same conductor thereby increasing power losses in wiring and forcing people to use thicker wiring which are heavier and more expensive.

This is one question that the article cited by the OP actually addresses ... so I suggest you read it.

[Brumby]

In North America we have both 110 and 220, the latter being for larger appliances.

No, we don’t. (I’m American.) We have 120V/240V. It hasn’t been 110/220V for over 70 years.

Patience, my friend.

It took me more than a year of browsing through this forum for that information update to come to light.

[Nusa]

In North America we have both 110 and 220, the latter being for larger appliances.

No, we don’t. (I’m American.) We have 120V/240V. It hasn’t been 110/220V for over 70 years.

Half-right. The nominal STANDARD has been 120V/240V for over 70 years. However, that standard was for new infrastructure. It took many decades for existing infrastructure to make the switch, so what you grew up with depended on where you lived. So way less than 70 years in practice. It's even possible there are still a few pockets left today, although I'm not aware of them.

You also have to remember it's a nominal service voltage. An actual utilization voltage of 110V at the customer plug in a house is low, but still acceptable within the current standard.

[Brumby]

So way less than 70 years in practice. It's even possible there are still a few pockets left today...

I keep this in the back of my mind as well.

[IanB]

The supply voltage is absolutely 120/240 where I live. I have measured it multiple times and it is regulated to within a couple of volts all through the day.

[poorchava]

Much of Europe delivers 3-phase power to most residences, and is similar to the US Wye system, except the voltages are 230 V line to neutral, and 400 V line to line.

The only European country where 3 phase for domestic installations is the norm is Germany. Domestic 3 phase exists elsewhere in European, but its not the standard practice. Most streets have 3 phase power, and they spread the phases out across the houses.

Not the only one. It's the same at least in Poland and AFAIK Czech Republic and Slovakia too.
It is true that there is rarely a 3-phase socket in apartments. Most electric kitchen stoves require 3-phase supply but they are usually wired directly to a terminal block in the wall. This is standard, as gas most new apartment complexes don't have gas. Loads other than ovens are usually just connected to different phases to even out the load.

With houses it is different. Many will have a 3-phase outlet in basement or garage. If they don't, it's usually the case of the owner not needing more than anything else.

Some older buildings don't have a separate PE wire. Before nineties the standard way was to use a PEN wire which is protective Earth and neutral at the same time.

[Vtile]

Bollocks there is no PME/MEN only TN-C-S according the specified IEC standards. 

[Vtile]

Much of Europe delivers 3-phase power to most residences, and is similar to the US Wye system, except the voltages are 230 V line to neutral, and 400 V line to line.

The only European country where 3 phase for domestic installations is the norm is Germany. Domestic 3 phase exists elsewhere in European, but its not the standard practice. Most streets have 3 phase power, and they spread the phases out across the houses.

Nope, this is norm also in atleast Finland and I'm pretty confident it is also standard in Sweden from some non-directly related material I have seen. Every new household will have 3-phase as the standards promote to wire the electric stoves as 3-phase, also traditionally the Saunas and other elecrical heating have been a major power hogs, so the 3-phase installations have been natural to have. Norway on the other hand have a bit more quirks IIRC compared the current IEC specifications.

[poorchava]

Another thing that usualy requires 3-phase power: at least here in Poland electrical floor heating has become quite popular over last few years because it is easier and cheaper to install in comparison to water systems and can easily be retrofitted in existing flats/houses. My house is about 160 sq.m of floor area, which at roughly 100W per sq.m is ~16kW. Good luck drawing that from a single phase (that is - aside from the fact that I actually happen to have a transformer station a few meters from the border of my property and I could potenttially get about 40kW per phase if I had that kind of money and needed to). And this is not a particularily large house or an exceptionally high-powered heatin system.

[IanB]

My house is about 160 sq.m of floor area, which at roughly 100W per sq.m is ~16kW. Good luck drawing that from a single phase

At 240 V that would be 67 A. If the house had a 100 A supply that would be achievable, although it would need some very thick wires.

[sibeen]

I have designed things for use on the Philippine networks and can honestly say it is the strangest thing ever. I have never seen an HV/LV transformer that is fed only one phase wire, relying on the ground to provide the return other than there. Mind you twice a day the poles were underwater so a good ground was never a problem.

Very common in Australia and New Zealand. It's called a SWER (Single Wire Earth Return) system. When you're running power out 100s of kilometres to feed voltageer to three people and a million rabbits it's an economical solution.

[paulca]

In North America we have both 110 and 220, the latter being for larger appliances.

No, we don’t. (I’m American.) We have 120V/240V. It hasn’t been 110/220V for over 70 years.

Patience, my friend.

It took me more than a year of browsing through this forum for that information update to come to light.

Similarly the change to the UK voltage that happened decades ago and lots of people still refer to the mains as 240V when it hasn't been for decades to bring it more inline with the 220V european standard.  I believe it is now 230V +/- 10%.

Older devices, in the 1970s/1980s used to have manual switches on the power inlets for 220V / 240V supplies, but these days they are almost all auto switching (or designed not to care).

[sibeen]

Australia did what the UK did, just a few years later. Our 'standard' voltage changed from 240 to 230 volts. Out actual delivered voltage changed this much ---><-------.

[richard.cs]

The UK is currently 230 V +10%/-6%, note the asymmetric tolerance, giving a range of 216 to 253 V, having previously been 240 +/-6%, 226 to 254 V. Nothing has changed except the specification. It's still 240 V nominal even on new installs, and a lot of substations are on the 250 V (433 V phase-phase) tap anyway giving voltages in the mid 240's to many customers. I measured mine as 239.9 V last night but routinely see around 246 V.

[jonovid]

Australia did what the UK did, just a few years later. Our 'standard' voltage changed from 240 to 230 volts. Out actual delivered voltage changed this much ---><-------.

in South Australia its 250 volts at the outlet.

[VEGETA]

Here in Jordan we have 220v single phase  @ 50 Hz. That is why we get "European plug" option when we buy from Ebay.

[IanB]

Similarly the change to the UK voltage that happened decades ago and lots of people still refer to the mains as 240V when it hasn't been for decades to bring it more inline with the 220V european standard.  I believe it is now 230V +/- 10%.

That's why I started this other thread.

The UK mains is still regulated to a nominal 240 V, even though there is a wide allowable variation. You could join in the fun and measure your own voltage to find out how close yours is.

[Paul Moir]

My house is about 160 sq.m of floor area, which at roughly 100W per sq.m is ~16kW. Good luck drawing that from a single phase

At 240 V that would be 67 A. If the house had a 100 A supply that would be achievable, although it would need some very thick wires.

In North America, a 200A service is normal for a house with electric heat.   100A would be about the smallest you would ever install nowadays, especially since 125A doesn't add much cost:  just slightly larger wires on the service.  Back in the '50s and '60s 60A was common around here which was enough to run your fridge, furnace, electric water heater, stove, lighting etc.  Unfortunately these got pushed over the edge by the popularization of the electric clothes dryer.

[richard.cs]

In North America, a 200A service is normal for a house with electric heat.   100A would be about the smallest you would ever install nowadays, especially since 125A doesn't add much cost:  just slightly larger wires on the service.  Back in the '50s and '60s 60A was common around here which was enough to run your fridge, furnace, electric water heater, stove, lighting etc.  Unfortunately these got pushed over the edge by the popularization of the electric clothes dryer.

In the UK supplies of between 60 A and 100 A are normal for domestic. Very large houses that need more power would be more likely to have 3-phase than to go above 100 A single phase. Most houses use natural gas as the primary source of heating, and many electrically heated houses use storage heaters which are heated overnight on cheap-rate electricity (when there are few other loads). Domestic clothes driers tend to be 2.5-3 kW here so they aren't a major consideration for us.

[Paul Moir]

Owing to the higher voltage then, the laws of physics haven't changed.  The 3-4kW the dryer took a good chunk of the 14kW available from those old 60A 240V services.
In my location, the price of domestic electricity is regulated which has so far not allowed variable rates.  Businesses are typically charged based on consumption and peak demand.  This means that there is no cheap rate for domestic, but large businesses might schedule loads to reduce their peak. 
Heat by combustion is very popular here naturally.  Where I live is gas deprived so heating by "fuel oil" (diesel) was by far the most common method.  It seems to me the popularity of electric heat was tied to the price of oil which is of course not so regulated.  This peaked in the 80s with both the price of oil being very high and interest rates being very high.  The capital cost of cheap resistive heaters is much less than that of a furnace.
Three phase is unfortunately not available in most residential districts by the nature of the distribution network.  A single conductor at typically 12.5kV-25kV is transformed down and feeds a few houses.  Three phase would require three wires and three transformers.  Out in the country they use a single conductor and a small single transformer for each house.

[tooki]

In North America we have both 110 and 220, the latter being for larger appliances.

No, we don’t. (I’m American.) We have 120V/240V. It hasn’t been 110/220V for over 70 years.

Half-right. The nominal STANDARD has been 120V/240V for over 70 years. However, that standard was for new infrastructure. It took many decades for existing infrastructure to make the switch, so what you grew up with depended on where you lived. So way less than 70 years in practice. It's even possible there are still a few pockets left today, although I'm not aware of them.

You also have to remember it's a nominal service voltage. An actual utilization voltage of 110V at the customer plug in a house is low, but still acceptable within the current standard.

Well obviously we are talking about the nominal voltage, if not otherwise specified! And in USA, the nominal voltage has been 120V for the better part of a century. That’s what we should be stating and encouraging, not 110 just because it’s still within spec if that happens to be the actual voltage.