Power supply in the United States versus Europe

[MetricRocketeer]

Hi TRF colleagues,

In the United States electricity is supplied in 120 volts, right? In Europe it is supplied about double that amount.

First, why is there a difference?

Second, which one is better, or does it not make a difference?

Thank you.

Stanley

 

[BEC]

I‘m going to be “that guy” here. For your purpose, define “better”.

I suspect the reason is simply how power systems evolved somewhat separately over time in different places, but that’s purely speculation on my part.

 

[mh9162013]

It's delivered at double the voltage, but are the amps delivered the same as the U.S. or half?

 

[rharshberger]

240v wired motors will come up to speed slightly faster than 120v motors and will have slightly more torque (on a motor that is capable of being dual voltage wired) for the same horsepower rating. I have seen where 240v circuits can use smaller wire for a given amperage than a 12v 20amp circuit for example, but have no personal experiance. Joule's Law comes into play here.

 

[dr wogz]

for the record: Japan: half the country is 100V 60Hz, and the other half is 100V 50Hz..

So, we need to have two configurations of our equipment when we send it over: one wired as for 'North America' and the others wired for 'Europe, but with some transformers..

 

[les]

Pros - higher voltage allows for lower current, hence thinner wires
Con - higher voltage is more hazardous and may require thicker insulation (but insulation is cheaper than copper)

As to why differences? As BEC stated, depends on how the systems evolved. Here in the US, for a while, there were 60Hz and 50Hz systems. It took a while before the US standardized on the 60Hz. Note that higher frequencies allow for smaller inductors and even motors.

 

[Steve Shannon]

It's delivered at double the voltage, but are the amps delivered the same as the U.S. or half?

Volts and frequency are held nearly constant while amps are drawn on demand in utility power systems worldwide. Devices use power, which is the product of voltage and current. When voltage is nearly twice as high, a device using the same power as one for the lower voltage system will use half the current, which can mean smaller wires.

 

[Funkworks]

 

[jderimig]

Blame US 120V on Thomas Edison. He invented a light bulb that was superior in life, output and cost. To get this performance his bulb was optimized to work at 110V. He also developed the whole generation and distribution system as well. The killer app for electricity at the time was light. By the time Tesla came up with a superior AC system the 110V standard in the US was well established.

 

[MetricRocketeer]

Hi TRF colleagues,

Thank you very much for the instructive responses and the links to the two great YouTube videos.

This explained a lot.

Stanley

 

[Woody's Workshop]

A 120v US vs 240v EU.
1/2 the amps to run the same device running on 120v.
I can not comment on which is better or preferred because I have never been to Europe or anywhere they use 240v for standard house type plugs.
I have been zapped by both 120v and 240v. The 120 makes your muscles contract (grip).
240 basically threw my hand away from it.
As for which is safest, that falls upon the person messing with electricity.
I did all the wiring myself in my wood shop and did both.
240 is not much different than 120 except there is one more wire and takes up twice the space in the electrical panel.

 

[Peartree]

The other significant difference that was mentioned but not discussed is the difference in frequency. The US is 60 Hz, while Europe generally is 50 Hz. Since 60 Hz is almost exactly the frequency of the nerve impulses that conrtrol the rhythm of the human heart (as I understand it), a shock from a 60 Hz, higher amperage system is far more likely to cause cardiac arrest than a shock from a 50 Hz, lower amperage system. For this reason, Europe's 50 Hz, 240 V is reputed to be significantly safer.

 

[MetricRocketeer]

The other significant difference that was mentioned but not discussed is the difference in frequency. The US is 60 Hz, while Europe generally is 50 Hz. Since 60 Hz is almost exactly the frequency of the nerve impulses that conrtrol the rhythm of the human heart (as I understand it), a shock from a 60 Hz, higher amperage system is far more likely to cause cardiac arrest than a shock from a 50 Hz, lower amperage system. For this reason, Europe's 50 Hz, 240 V is reputed to be significantly safer.

This is noteworthy.

 

[user 30299]

The other significant difference that was mentioned but not discussed is the difference in frequency. The US is 60 Hz, while Europe generally is 50 Hz. Since 60 Hz is almost exactly the frequency of the nerve impulses that conrtrol the rhythm of the human heart (as I understand it), a shock from a 60 Hz, higher amperage system is far more likely to cause cardiac arrest than a shock from a 50 Hz, lower amperage system. For this reason, Europe's 50 Hz, 240 V is reputed to be significantly safer.

I'm glad you used the word "reputed".

I don't think the European's believe 50hz, 240v (220v) is significantly safer. I help in the design & installation of industrial equipment,
made in the US and Canada, that will be used overseas. We are not allowed to have any components that operate at 220v, such as
pushbuttons, that an operator can come in contact with while using the equipment. We build all consoles to work with low-voltage DC,
typically 24-volt. And it's been that way long before we started putting HMI's and joysticks in the consoles. 220-volts is 220-volts, so no
matter the Hz, it will still knock you on your ass.

Thanks to personal experience (lol), from years of installing and servicing industrial equipment, always confirm that "the other guy"
actually threw the disconnect and locked out a machine. (The fancy term is "de-energize".)

 

[dhbarr]

I'm glad you used the word "reputed".

I don't think the European's believe 50hz, 240v (220v) is significantly safer. I help in the design & installation of industrial equipment,
made in the US and Canada, that will be used overseas. We are not allowed to have any components that operate at 220v, such as
pushbuttons, that an operator can come in contact with while using the equipment. We build all consoles to work with low-voltage DC,
typically 24-volt. And it's been that way long before we started putting HMI's and joysticks in the consoles. 220-volts is 220-volts, so no
matter the Hz, it will still knock you on your ass.

Thanks to personal experience (lol), from years of installing and servicing industrial equipment, always confirm that "the other guy"
actually threw the disconnect and locked out a machine. (The fancy term is "de-energize".)

Yeah, witnessing the live-dead-live and putting my lock on with the others makes me feel a lot better. If I only I could get rid of that nagging feeling about the diagrams vs. as-built....

 

[user 30299]

Yeah, witnessing the live-dead-live and putting my lock on with the others makes me feel a lot better. If I only I could get rid of that nagging feeling about the diagrams vs. as-built....

Oh yeah, I've had that "exciting" experience of diagrams vs. as-built.

 

[Banzai88]

Oh yeah, I've had that "exciting" experience of diagrams vs. as-built.

I've worked on too many ships and aircraft, that ALL have a lifetime of service techs personalities and interpretation of how it ought to be wired (or repaired, or modified) to EVER rely on the supposed as-built diagrams! Fool me once.......

 

[Peartree]

I'm glad you used the word "reputed".

I don't think the European's believe 50hz, 240v (220v) is significantly safer. I help in the design & installation of industrial equipment,
made in the US and Canada, that will be used overseas. We are not allowed to have any components that operate at 220v, such as
pushbuttons, that an operator can come in contact with while using the equipment. We build all consoles to work with low-voltage DC,
typically 24-volt. And it's been that way long before we started putting HMI's and joysticks in the consoles. 220-volts is 220-volts, so no
matter the Hz, it will still knock you on your ass.

Thanks to personal experience (lol), from years of installing and servicing industrial equipment, always confirm that "the other guy"
actually threw the disconnect and locked out a machine. (The fancy term is "de-energize".)

Low voltage is always going to be safer. But, I've had a number of European friends and colleagues ask how we could ever feel safe living in homes that had 60 Hz flowing through our wiring. Perception is everything, I suppose.

 

[boatgeek]

Oh yeah, I've had that "exciting" experience of diagrams vs. as-built.

I've worked on too many ships and aircraft, that ALL have a lifetime of service techs personalities and interpretation of how it ought to be wired (or repaired, or modified) to EVER rely on the supposed as-built diagrams! Fool me once.......

This made me laugh a bit--I'm presently in the middle of doing a set of as-built drawings for a new construction project. It wasn't even out of the yard before they wired stuff differently from our drawings! And this is for a relatively picky owner who actually wants as-builts. Some of our clients aren't willing to pay for that service up front, so naturally they pay for it in spades later.

Pros - higher voltage allows for lower current, hence thinner wires
Con - higher voltage is more hazardous and may require thicker insulation (but insulation is cheaper than copper)

As near as I can tell from the scraps around the house, "standard" insulation on residential grade wires is good for 600V, so there shouldn't need to be extra insulation.

 

[jqavins]

Volts and frequency are held nearly constant while amps are drawn on demand in utility power systems worldwide. Devices use power, which is the product of voltage and current. When voltage is nearly twice as high, a device using the same power as one for the lower voltage system will use half the current, which can mean smaller wires.

And if/when equal size wires are used, it means less voltage drop in the wires, and thus less lost power.

a shock from a 60 Hz, higher amperage system...

Stop right there. The 120 V system is made to provide higher maximum current. It does not push more current through a given object. I=V/R, and the resistance of a European person is not significantly different than that of an American person. The higher voltage will push higher current through your body, and is (as far as I know) more likely to kill you. I don't know about the cardiac signal frequency aspect, but the notion that it more than makes up for doubling the current passing through those muscles and nerves does not pass the smell test for me.

Low voltage is always going to be safer. But, I've had a number of European friends and colleagues ask how we could ever feel safe living in homes that had 60 Hz flowing through our wiring. Perception is everything, I suppose.

Yes, I know I could be wrong, but that sounds like it belongs in the same file as fan death.

If I only I could get rid of that nagging feeling about the diagrams vs. as-built....

Don't. Don't ever get over that feeling. That feeling helps keep you alive.

As near as I can tell from the scraps around the house, "standard" insulation on residential grade wires is good for 600V, so there shouldn't need to be extra insulation.

The rating is 600V (if you've read it right, which I'm ready to assume). But as you know, there are derating factors, safety factors, etc. I don't know if European household wiring needs 1200 V rated wire, but I wouldn't say "600 is plenty more than 240, so it's fine.)

 

[boatgeek]

The rating is 600V (if you've read it right, which I'm ready to assume). But as you know, there are derating factors, safety factors, etc. I don't know if European household wiring needs 1200 V rated wire, but I wouldn't say "600 is plenty more than 240, so it's fine.)

Point well taken. That said, the 240V wire has less current and therefore less heat generation if they are powering the same load and also if the wire is rated to 600V, presumably it isn't going to short through the insulation until it reaches that voltage. We have now exhausted the sum total of my electrical engineering knowledge.

I also would never presume to take US standard wire and install it in Europe. No doubt they have different material and installation standards for wire over there.

 

[rharshberger]

And if/when equal size wires are used, it means less voltage drop in the wires, and thus less lost power.


Stop right there. The 120 V system is made to provide higher maximum current. It does not push more current through a given object. I=V/R, and the resistance of a European person is not significantly different than that of an American person. The higher voltage will push higher current through your body, and is (as far as I know) more likely to kill you. I don't know about the cardiac signal frequency aspect, but the notion that it more than makes up for doubling the current passing through those muscles and nerves does not pass the smell test for me.


Yes, I know I could be wrong, but that sounds like it belongs in the same file as fan death.


Don't. Don't ever get over that feeling. That feeling helps keep you alive.


The rating is 600V (if you've read it right, which I'm ready to assume). But as you know, there are derating factors, safety factors, etc. I don't know if European household wiring needs 1200 V rated wire, but I wouldn't say "600 is plenty more than 240, so it's fine.)

12-3 (typical romex type, not thhn) wire can be used for both 120v and 240v depending on the length of run and amperage carried. THHN can be used in similar situations but has different installation requirements.

 

[les]

Not certain about the difference between 50/60Hz, but I can say 400Hz (aircraft power) bites harder.
Ask me how I know............

And I agree with jqavins, current across the heart is the killer, not the voltage. With 220 (and the infamous I=E/R), with a given body resistance, doubling the E doubles the I. Hence I would think the higher voltage is MORE hazardous.

I found this info on the web
Currents greater than 75 mA cause ventricular fibrillation (very rapid, ineffective heartbeat). This condition will cause death within a few minutes. Heart paralysis occurs at 4 amps, which means the heart does not pump at all. Tissue is burned with currents greater than 5 amps.

 

[ksaves2]

Blame US 120V on Thomas Edison. He invented a light bulb that was superior in life, output and cost. To get this performance his bulb was optimized to work at 110V. He also developed the whole generation and distribution system as well. The killer app for electricity at the time was light. By the time Tesla came up with a superior AC system the 110V standard in the US was well established.

I was going to say I found this thread very interesting but thought it would be superfluous. Thought I hit cancelled but apparently hit the wrong button. Sorry. Kurt

 

[heada]

Houses in the US have 240v service as 2 phases of 120v. That's how AC, electric stoves and dryers work (as well as my MIG welder, tablesaw, bandsaw, jointer and planer) The house runs are typically split between phases so any single run is 120v but it's possible to get 240v if you run 2 hot, 1 neutral and 1 ground.

 

[ksaves2]

Blame US 120V on Thomas Edison. He invented a light bulb that was superior in life, output and cost. To get this performance his bulb was optimized to work at 110V. He also developed the whole generation and distribution system as well. The killer app for electricity at the time was light. By the time Tesla came up with a superior AC system the 110V standard in the US was well established.

Wasn't Edison "big guns" on D/C current that was so inefficient for distribution over Westinghouse's AC distro?
Plus AC was better to execute capital crimes criminals which is one thing Edison tooted his horn on for the safety of DC current. I think the only problem was there would have to be a generating plant every something like 6 blocks in a neighborhood. The house at the end of the chain would have dimmer lights on DC. AC distribution is more efficient and transformers can bump up or down the voltage as needed. Imagine the freaking coal smoke coming out of the boiler/generators every 6 blocks in a neighborhood if Edison's DC plan was made the standard!
Westinghouse won out and it's what we have today thank heavens 'cause the power can be sent over long distances more efficiently. Yeah, AC can kill you but one just has to be careful!
I have plenty of "gizmos" to plug into the wall if I want DC (o.k. so maybe pulsed DC but my devices don't know the difference from a battery!) I can get DC whenever I want. George Westinghouse did good.
Kurt

 

[jderimig]

Wasn't Edison "big guns" on D/C current that was so inefficient for distribution over Westinghouse's AC distro?
Plus AC was better to execute capital crimes criminals which is one thing Edison tooted his horn on for the safety of DC current. I think the only problem was there would have to be a generating plant every something like 6 blocks in a neighborhood. The house at the end of the chain would have dimmer lights on DC. AC distribution is more efficient and transformers can bump up or down the voltage as needed. Imagine the freaking coal smoke coming out of the boiler/generators every 6 blocks in a neighborhood if Edison's DC plan was made the standard!
Westinghouse won out and it's what we have today thank heavens 'cause the power can be sent over long distances more efficiently. Yeah, AC can kill you but one just has to be careful!
I have plenty of "gizmos" to plug into the wall if I want DC (o.k. so maybe pulsed DC but my devices don't know the difference from a battery!) I can get DC whenever I want. George Westinghouse did good.
Kurt

Actually HV DC transmission lines are superior to A/C but back in the early 1900's there wasn't cheap tech to step up the voltage. Today there is.
Advantages of an HV DC grid:
1. Do not have to synchronize transmission line frequency.
2. Insensitive to ground level potential differences over long distances. Transformers hate DC current which which is why DC blocking capacitors are needed along the line. Expensive and a point of failure. (See 1989 Quebec Hydro blackout, they didn't have enough capacitors in their grid).
3. As above, insensitive to solar flare (or EMP) induced DC on line that blows up transformers. Transformers are expensive and in short supply.
4. Compatible with DC and unsynchronized sources of power, (solar, battery storage, unsynchronized windmills).

Edison had it right, he was just too early.

 

[Sandy H.]

Actually HV DC transmission lines are superior to A/C but back in the early 1900's there wasn't cheap tech to step up the voltage. Today there is.
Advantages of an HV DC grid:
1. Do not have to synchronize transmission line frequency.
2. Insensitive to ground level potential differences over long distances. Transformers hate DC current which which is why DC blocking capacitors are needed along the line. Expensive and a point of failure. (See 1989 Quebec Hydro blackout, they didn't have enough capacitors in their grid).
3. As above, insensitive to solar flare (or EMP) induced DC on line that blows up transformers. Transformers are expensive and in short supply.
4. Compatible with DC and unsynchronized sources of power, (solar, battery storage, unsynchronized windmills).

Edison had it right, he was just too early.

I think I'm on-board with your general statements above and definitely don't have a background that would let me dispute them. I think the most important part of your post, though is: ". . . he was just too early."

Regardless of whether DC or AC is best, at the time of implementation and growth of the industrial revolution, AC did win the battle of the currents. I don't know what would have happened to the US or the world if we had to wait for DC to be able to run long distances, given the general troubles at the time of raising and lowering DC voltages, which we can do much easier today, likely because we could move forward technology faster due to having AC power!

The unfortunate part is the massive infrastructure we have in place. By being an early adopter/leader, our infrastructure is based on 60Hz AC and I can't imagine what it would take to switch to a more efficient and effective method. I believe certain 'backwards' countries couldn't put in copper phone lines and had nothing, but once cellular tech was available, they were financially able to start that infrastructure. For a while, some of those countries had a more robust system than we did - all anecdotal information and possibly false, but I could believe in concept for sure. I could see the same thing being true for the electrical grid.

Interesting discussion for sure.

Sandy.

 

[jderimig]

I think I'm on-board with your general statements above and definitely don't have a background that would let me dispute them. I think the most important part of your post, though is: ". . . he was just too early."

Regardless of whether DC or AC is best, at the time of implementation and growth of the industrial revolution, AC did win the battle of the currents. I don't know what would have happened to the US or the world if we had to wait for DC to be able to run long distances, given the general troubles at the time of raising and lowering DC voltages, which we can do much easier today, likely because we could move forward technology faster due to having AC power!

The unfortunate part is the massive infrastructure we have in place. By being an early adopter/leader, our infrastructure is based on 60Hz AC and I can't imagine what it would take to switch to a more efficient and effective method. I believe certain 'backwards' countries couldn't put in copper phone lines and had nothing, but once cellular tech was available, they were financially able to start that infrastructure. For a while, some of those countries had a more robust system than we did - all anecdotal information and possibly false, but I could believe in concept for sure. I could see the same thing being true for the electrical grid.

Interesting discussion for sure.

Sandy.

We will see a hybrid going forward. Local distribution to our homes and offices will continue to be a/c and transformers, not a big disadvantage even though almost nothing in our homes runs on AC anymore(except for my tube audio amplifier running a 1960 era circuit that no current solid state amp can touch sonically, but that is the subject for another thread). DC is already making in-roads in connecting our regional grids as its a elegant solution to the synchronization problem.

 

[rocket_troy]

not a big disadvantage even though almost nothing in our homes runs on AC anymore

I'd be surprised if that was the case. Anything with a mains motor in it will only work on AC - washing machines, dryers, floor/ceiling/exhaust fans, fridges, Air Cons, convection ovens (probably microwave too), pool pumps, garage door motors, etc.

TP