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Welcome!
On this page I'm going to give you some straight answers about whether your American
electrical and electronic devices will work in other countries, where the line voltage is different.
This is a subject on which confusion and misinformation are rampant, and mistakes can
be dangerous.
My qualifications: I am a faculty member at The University of Georgia as well as
an independent consultant, and for several years I authored the "Q&A" column in
Electronics Now magazine.
I am also a seasoned international traveler.
Summary of main points
- Your equipment may or may not be compatible with the line voltage and frequency
in the country you are visiting. To find out, read the placard on the equipment.
- If your equipment is compatible with the local line voltage and frequency,
all you need is a plug adapter so that you can connect the plug to a foreign socket.
- If your equipment is not compatible with the local line voltage and frequency,
you may be able to use a voltage converter (which is tricky and risky), but my
recommendation is not to bring it along at all.
- Trial and error are dangerous. Risks include electrocution and fire (immediate
or delayed). Don't assume a fuse or circuit breaker will protect you if you do
something wrong.
- Audio recordings (records, tapes, and CDs) are the same worldwide. Movie DVDs,
however, are licensed for specific regions and will not play on DVD players elsewhere
even though the technology is the same.
- Radios generally work everywhere, except that digitally tuned radios may not be
able to tune to the frequencies used in other countries. (Example: American AM stations
are all on multiples of 10 kHz; European ones aren't.)
- TV channels and broadcast signals differ from country to country and you can generally
use a TV set only in the country for which it was designed.
- If you move overseas, bring only small appliances that are definitely compatible with
the new country's line voltage and frequency. Your TV, microwave oven, and even hair dryer
should be left behind.
Understanding line voltage and frequency
The two things to know about the AC power in any country are the
voltage (measured in volts) and the
frequency (measured in Hertz, Hz, or cycles per second).
The United States uses 120 volts, 60 Hz, as do Canada and Mexico.
Most of Europe and Asia use 230 volts, 50 Hz.
Japan uses 100 volts, 50 or 60 Hz depending on region.
You can find out the voltage and frequency used in any country from
this web site
or, better, from the embassy or tourist office of the country you are
visiting.
Small differences of voltage do not matter.
The European system has been specified as 220, 230, or 240 volts.
The American system has at various times been specified as 110, 117,
120, or 125 volts.
American 120-volt equipment often works, with reduced performance, on Japanese 100-volt power,
since historically the American line voltage has long been 110 volts or lower in some places.
However, beware of motors that fail to start turning; they can overheat and burn out.
Do not use Japanese 100-volt equipment on American 120-volt power unless its label clearly
states that 120 volts is OK.
Frequency matters if electric motors are involved. I found out the
hard way that a 60-Hz motor runs very poorly on 50 Hz, even if the voltage is
correct. Many devices, however, accept both 50 Hz and 60 Hz.
There are 240-volt outlets in America for heavy appliances, but it is not safe
to plug 230-volt European appliances into them. The reason is grounding.
An American 240-volt outlet is actually split-phase, with one wire 120 volts above
ground and the other 120 volts below ground (to oversimplify a little). In Europe, the
"neutral" side is close to zero volts above ground (just like the "neutral" wire
in the American 120-volt system). Thus, running an European appliance on
American 240-volt power introduces an unexpected shock hazard.
British bathrooms often have 120-volt electric shaver outlets that contain
isolation transformers and accept American plugs.
These are safe for electric shavers and other very
low-power gadgets such as cell phone chargers.
Reading the placard on your equipment
How do you find out whether your equipment will work on foreign power?
Read the label! For decades, every electrical or electronic device has been
required to have a label giving its exact power requirements.
You are looking for the AC input voltage (marked "AC" or "~") and frequency (marked "Hz" or "~").
For example,
here's a recent-vintage Conair hair dryer:
You can see that it requires 125 volts (actually the American range of voltages, nominally 120),
60 Hz, and nothing else.
Leave it at home.
Here's an example of the wave of the future: a laptop power supply that
accepts everything from 100 to 240 volts, 50 to 60 Hz. This is made possible
by new integrated-circuit voltage regulators. You can use it anywhere with
only a plug adapter.
Here's a vintage-1970s radio that requires 120 V, 60 Hz. In fact, because it doesn't
contain an electric motor, it is actually not sensitive to frequency and I used it
successfully on 50 Hz during one trip.
Finally, here's a computer with a switch to select nominal 115 or 230 volts.
It can be used anywhere with an appropriate cord and plug.
Be sure to set the switch correctly before plugging it in!
Otherwise you'll destroy the power supply immediately.
Fortunately, replacement parts for PCs are the same worldwide.
What about voltage converters?
It is vitally important to distinguish a plug adapter, which contains no
electronic components and merely connects an American plug to a socket of a different
shape, from a voltage converter that actually changes the line voltage.
You can buy voltage converters at Radio Shack and in airports, and if you're not careful,
you can use them to destroy your equipment. I recommend avoiding them in this day and age.
In the past, they were often necessary.
To choose a voltage converter, you need to know not only the voltage, but also the
wattage or amperage required by your equipment. For example, the Conair hair dryer
above requires 1,875 watts (and says so). The radio only wants 6 watts.
If you encounter something marked "1.5 amps" or "1.5 A" you can use the formula
Watts = volts × amps
to deduce that at 120 volts, it requires 180 watts.
There are two types of voltage converters,
transformer-type and rectifier-type.
Transformer-type voltage converters are heavy (for their size, containing lots
of solid metal) and have relatively low wattage limits (like 25 to 50 watts
for a pocket-size device, or 500 watts for a transformer that weighs 10 pounds).
They produce safe, authentic alternating current at the desired voltage, but they
do not change the frequency.
They are for small, low-power devices only.
This is what I used with my 1970s radio in England, and it worked fine, but nowadays,
most low-power devices are already compatible with a wide range of voltages and don't
need a converter.
The other type is a rectifier-type or thyristor-type voltage converter.
It is small, lightweight, and able to deliver lots of watts (up to 1500 or more),
but is only for lights and heating elements.
This type of voltage converter will damage other types of equipment.
Rectifier- or thyristor-type converters work by cutting off part of each pulse of alternating
current. You still get 240 volts, but in pulses half of their normal width.
This is fine for 120-volt devices that are using electricity only as a source of heat.
So if you must take your American electric teakettle to
England (as if the English had none of their own!),
this is the solution. Photographers sometimes use these with photoflood lamps,
but why not just buy 240-volt bulbs locally?
What about audio, video, radio, and TV?
When I started to travel internationally, I was relieved to find that audio media
(records, tapes, and CDs) are the same all over the world. They still are.
DVDs of movies, however, are encoded for the region in which the movie is licensed,
since different companies sell the same movie in different places.
You may find that if you buy DVDs overseas, your American player won't play them.
Of course, this will not affect homemade DVDs or educational DVDs that are distributed free
and not locked to regions.
You may also run into difficulty because of different screen formats (525-line versus 625-line, etc.);
this is unlikely to be a problem if you use a computer for playback.
Analog (conventional AM and FM) radios should work everywhere, except for a couple of things.
The AM (MW) and FM (VHF)
broadcast bands are the same everywhere, but the exact channel frequencies are not,
and that can cause a problem with digitally-tuned radios.
For example, American AM stations are on multiples of 10 kHz (such as 1340 and 1350 but
not 1345 or 1348) and other countries follow a different system; a digitally tuned radio that tunes only
to the American channels will have problems.
The FM band has the same problem; Americans use odd-numbered multiples of 0.1 MHz
and other countries are under no such constraint.
True digital radio services (satellite and direct-broadcast digital)
differ widely from country to country.
You generally can't use a TV set in any country except the ones it was made for.
Not only are we in the middle of the transition to digital broadcasting, but even before that,
the standards were wildly different from country to country.
This also applies to devices such as cameras that connect to TVs, such as cameras,
camcorders, and video games.
The most common difference is between PAL (British-style) and NTSC (American-style)
analog video signals.
Wi-Fi works the same way everywhere, but its availability varies from country to country;
Japan, for instance, is moving quickly to 3G (cellular) wireless.
The situation with cellular telephones is complicated and changing very fast.
Avoid international roaming — that is, don't use your American cell phone
and American carrier while abroad; even though it works like a charm, that service is very expensive.
Instead, check with a specialty dealer who sells cell phones and SIM cards for international
use. In most countries the best tactic is to buy a local SIM card,
together with a phone card to enable you to call America cheaply.
You will of course need to get your cell phone "unlocked" so that it can accept SIM cards
from more than one carrier.
I'm moving overseas. What electrical appliances should I bring with me?
Nothing that is big or consumes a lot of power. Laptops, computers, and small radios are
good things to bring along. Kitchen appliances, microwave ovens, power tools, and TV sets
are not.
Copyright 2012 Michael A. Covington. Caching in search engines is explicitly permitted.
Please link to this page rather than reproducing copies of it.
This page is not in any way connected with or endorsed by any
manufacturer or vendor. Many of the product names that appear
on this and related pages are registered trademarks of their respective owners.
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