This is a question about electrical safety in Japan. I know this isn’t a Japanese forum, but my Japanese isn’t up to much, and everyone I can ask either knows nothing about electrical safety or nothing about Japan.

I come from the UK, where every plug is three-pronged and ordinary consumers like me don’t have to think about matters like grounding.

Here in Japan, most plugs are two-pronged. Risky devices like washing machines and dishwashers come with an extra green and yellow ground wire bolted onto the back. In my 80s apartment there are a couple of power sockets with a little metal plate where I can attach a ground wire; one is in the place where you’d expect a refrigerator to go, and the other is for the washing machine. It seems that the builders didn’t anticipate other kinds of home appliance.

So now I have a dishwasher, and it’s nowhere near any of the grounding plates. But it is near the kitchen range, and the kitchen range has a couple of gas taps attached. I am vaguely aware that gas pipes should be grounded, so I considered connecting the ground wire to the sink, but on closer inspection, it appears that the gas taps and the sink do not make electrical contact -- a 1 inch ring of uPVC separates the two.

The pipe work is safely sealed away from incompetent amateurs like me, so I can’t start hunting for evidence of grounding work there. However, the kitchen range does appear to have electrical contact (through metal pipes) to a gas water heater just above the kitchen range. The gas water heater is, in turn, connected to one of the gas taps via what appears to be a rubber hose. I don’t see any other signs of grounding, and the water heater was professionally installed so, at first glance, this suggests that the kitchen range is grounded.

So, what should I do? Shall I just connect the dishwasher to the sink, or am I going to have to bite the bullet and run a long wire to the refrigerator’s ground plate?

Many thanks for taking the time to read this.

  • 5
    The sink is not ground. If you ground to the sink, and then developed a ground fault. Touching the sink will give you a nasty surprise.
    – Tester101
    Mar 10, 2012 at 13:42
  • Could you please post a picture of your plug and the outlet? I did something similar to what you are trying to do when I lived over there.
    – J Crosby
    Jun 10, 2019 at 20:54

1 Answer 1


You can't rely on the integrity of the ground/earth on the pipework of the sink. For all you know it could be connected to PVC pipework further down. In the U.K all pipework is meant to be cross-bonded which is then taken to the earthing bar. However in Japan I am unsure if this is what is done. Regardless you should be earthing/grounding it back to the incoming supply.

In a lot of countries that use two pronged devices they are actually fed from centre-tapped transformers or are double insulated devices. Either way they should not become dangerously live.

In short don't connect to the sink run it back to the earthing/grounding bar.


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