This is more a question for curiosity, as I don't have a 240 volt appliance nor do I plan on visiting Europe.

As far as I have been able to tell, much of Europe uses the CEE 7 standard for household receptacles, which (I think) consists of 1 hot leg at 230 volts and 1 neutral.

The American standard is of course two alternating hot legs, each at 120 volts, which can be used individually (with a neutral) to supply 120 volts, or together (but without a neutral) to supply 240 volts.

Original question:

Other than the slight difference in voltage, and the utility frequency difference (60 Hz vs 50 Hz), does the actual equipment (say a motor) even notice a difference? Can it even tell that the current is being supplied by 2 alternating hot legs vs 1 hot leg and a neutral?

Editing the question for clarity, because I have a specific gap in my knowledge that I am trying to understand: (Ok, I have more gaps than just one, but this question is focusing on one.)

To make things more comparable, imagine a magical world where Europe uses 240 volts instead of 230 volts, and 60 Hz instead of 50 Hz. Now in this hypothetical situation, the major difference we face is:

  • in America we have 2 alternating hot legs, and--
  • in Europe they have 1 hot leg and a neutral.

What differences, if any, would be noticed by equipment such as a motor?

3 Answers 3


Yeah, a motor is going to care a lot about the different frequency. A lot. So will anything involved with induction.

Other than that, Mrs. Lincoln... The main difference is that Euro power is corner grounded whereas North American is center grounded. European plugs also aren't very good at being polarized, so a Euro device must have 230V of insulation value from each conductor to ground. It will handle North American power, 120V from ground, just fine.

A North American machine only expects to be insulated 120V from ground, so it may have to contend with higher voltage than it's been tested/listed for.

  • I know the frequency difference can cause problems. In the last paragraph I said I was looking for effects other than those caused by frequency, but I do admit I wasn't very clear on that. I think the information you provided on conductor insulation is relevant to what I was asking. Thank you.
    – Lakey
    Oct 28, 2017 at 2:24

Some gear cares about where the N-G bond lives

There are pieces of equipment (such as line-interactive inverters) that care deeply about how the N-G bonding is done for design and safety reasons. Because of this, they are a bit...pickier than other pieces of gear -- using an European solar inverter in the USA, or vice versa, would be rather unwise and could lead to some serious magic smoke emissions, even. More straightforward utilization equipment (such as motors and heaters) won't care about the location of the N-G bond, though.

Motors care, but due to frequency

Most AC motors are sensitive to frequency even if the voltage is the same. So, you won't get good results with a 240V 60Hz motor on 50Hz, or vice versa. Inverter drives, OTOH, don't care -- inverter appliances and VFDs will likely shrug at the mains frequency change.


In the 1960's we used US tape recorders in the UK with a 240 to 120 volt transformer and running at 120 volts 50 cycles and the only difference was the speed of the tape was affected, it was slightly slower on 50 cycles but only a little. Some people didn't even notice.


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