I’m going to be moving to Japan from Germany soon. The PC I use most is a desktop; its PSU is specified at 220–240 V input as is the European standard. Japan uses 100 V mains power as we all know.

I assume that the lower voltage will mean that I will not be able to use my PC’s current PSU in Japan out of the box. What options do I have to make it work?

Note that I heavily use the PC and sometimes leave it churning through data overnight. Thus, any suggestion should be applicable for excessive usage, too.

  • 2
    If you're handy with a screwdriver you could probably replace your PC's existing power supply with one suited for a lower supply voltage. But first make sure that yours doesn't have a little switch on it to select between 220-240V and 110-120V (usually right next to the power socket). Many do have this switch (or at lest they used to the last time I looked...)
    – brhans
    Commented Jun 13, 2017 at 21:24
  • @brhans Yeah, mine doesn’t. I actually did consider buying a 100 V-accepting PSU as one of the options and still expect it to turn up as an answer eventually ;)
    – Jan
    Commented Jun 13, 2017 at 21:31

2 Answers 2


Most PC power supplies nowadays can take a wide range of voltages, without the need for a manual switch. For example, the HP Z420 workstation cites an operating voltage range of 90–269 VAC, and a rated voltage range of 100-240 VAC. (Importantly for the Japanese case, it can also take both 50 and 60 Hz AC.) If your computer's from one of the big OEMs, this information should be available online.

Thus, the first thing I'd do is look more closely at your current power supply and confirm that it won't work as-is. If so, and you've got a standard ATX/EPS power supply, I'd then probably buy an appropriately-specced PSU before moving, to avoid the hassle of buying one while trying to settle in a foreign country.

Incidentally, if you're anything like me, you'll want to bring your own keyboard. Most keyboards in Japan are JIS, with some US ANSI. ISO layout is almost nonexistent.


You have two options:

  1. Use your PC as is with an external 110-to-220V transformer. Straightforward, but make sure the transformer's wattage is sufficient for your PC and that it's a high-quality model suitable for extended use. (Cheap, underpowered ones have a disturbing tendency to catch fire if overloaded for long periods of time.)

  2. Replace your PC's power supply (PSU) with a Japanese model. Power supplies are cheap and fairly standardized, so this is pretty straightforward and shouldn't require anything more than a screwdriver, but do double-check the physical dimensions, output voltage and the type and number of output plugs to make sure the replacement is compatible.

  • Replacing the power supply shouldn't be underestimated. It's not difficult, but it will require research, patience, and persistence, because every component inside the PC connected to the old supply will need to be re-connected to the new one, not to mention undoing and re-doing cable-ties. Plus you add the risk of damaging something while you're poking around. So if you're up for it, it's probably a nice option, but the transormer is the simplest option. Commented Jul 9, 2017 at 23:23

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