Electrical outlets in Japan - why no ground prong?

I was checking to see what sort of adaptor I would need for my two electrical devices to get them to fit into outlets in Japan. I was told that the outlets are the same as U.S. ones except they are all 2-prong outlets?

So no appliances need to use the ground prong? Or whatever it’s technical name is? I know that Japan is on a 100-volt system. Does that make a difference.

The lack of a ground doesn’t bother me as the only two things I’m bringing over are chargers. One for the battery in my camera and the other for my iPOD and both are rated to work at 100 volts.

Indeed, electrical outlets in Japanese residences are not grounded. When an appliance like an air conditioner is installed, special grouding must be done for outlet. In that sense, Japanese electrical outlets are like most U.S. electrical outlets before the 1970s, when grounded outlets became the standard under electrical codes.

According to this page, Japan uses the same outlet styles as in North America, but are predominantly ungrounded.

Personally, the only time I’ve ever seen the two-prong/no-ground style outlet as described on that page is in bathrooms for the “razor only” outlet that I presume is special in other ways.

This seems really inconvenient/possibly unsafe to me - what happens in Japan if you buy a refrigerator, PC, kettle, drill, etc. etc.? Do you have to have an electrician install a grounded outlet and then only use your device in that room, or perhaps the device is made with an ungrounded cord? If you don’t have one, do you just find some side cutters and mod your cord? :confused:

I would assume those appliances would be sold without a grounding prong. That’s how it is in Russia IIRC.

The things wich particularly need it have a extra cable with a forked tongue-shaped copper plate at the end. On the outlets near the area where one would plug in his refrigerator or washing machine, there is a flap at the bottom which if you lift up reveals a screw that sandwiches two copper plates (that are then linked to ground.) So you just loosen the screw and wedge the tongue plate in and screw it back down.

See post #2, above.

Refrigerators, washing machines and other high-risk appliances usually come with a separate ground wire, and most modern houses (perhaps past 15 years) have separate ground connections where those appliances are intended to be installed.

PC, kettle, drill, etc. are double insulated, and the ground wire is not absolutely necessary. My personal suspicion is that the Japanese think good quality control is enough to insure safety.

Grounding systems don’t work in Japan anyway. The land mass of the islands is too small to sufficiently take up the misdirected electricity.


Grounding finally became part fo the NEC in the US just about the same time we switched from making most small appliance/devices with metal covers to making them with plastic covers.

A 3rd wire ground is virtually useless for a non-metallic device. The Japanese simply bypassed solving yesterday’s problem. Double insulation is used in the few items with metallic cases such as some toasters and most/all fridges & washing machines.

A GFCI is in fact a much better solution than a 3rd ground wire. We’d do better to quit wasting 1/3rd of the copper in any installation and use the savings to put GFCI inline everywhere.


I’ve been up for about 20 hours and I was this close to believing that before I came to my senses. Well done.

FYI, toasters are never grounded. Even the 100% metal ones. It’s safer that way.

I disagree.

While I’m an advocate of GFCI protection, 3rd-wire grounding has some distinct advantages, namely:

  1. With a ground wire, the chassis is always at ground potential. Nothing is safer than this. If you replace the ground wire w/ a GFCI, and there’s a ground fault, and if the chassis is isolated, the GFCI trips only after some current has flowed through you (assuming you’re grounded). I don’t like this arrangement. What if the GFCI is faulty, and trips at 100 mA instead of 5 mA? Or what if it’s too slow?

  2. GFCIs are prone to failure, especially after a lightning storm. Even worse, they tend not to be fail safe.

The best arrangement for a device w/ metal chassis is both GFCI protection and 3rd-wire ground. But if I had a choice of only one, I would choose the latter.