ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades Japan - No grounds?

DullDull:

China or Japan? China uses the ungrounded North American plug and the grounded Australian plug. I don't know how the grounded sockets are connected, but in theory you can use the neutral for ground too. It was done this way on US dryers and ranges as well as German grounded sockets.

BTW: China sockets can look like this:



[This message has been edited by C-H (edited 01-27-2003).]

In Ireland they just don't mess about with grounding generally taking a "keep it simple stupid" approach. Every socket outlet is grounded all lighting points (fittings and switches) now must have a ground connection provided (even if not used) to make changing to metal/brass fittings is safe and easy.

Grounding is usually achieved with a large standardized grounding rod installed onsite by the electrician (and builder) and tested and approved by the ESB (Electricity Supply Board). You'll occasionally see the concrete cover over the top in the middle of a patio or on the side walk marked "Earthing Rod or Grounding Rod" There are regulations requiring the cables going to it to be clearly marked and protected too.

All plumbing (water and gas) must be bonded (fitted with earthing/grounding straps and wired together with green/yellow cable) to ensure that no pipework can ever become live due to an electrical fault. This is an issue paricularly considering that in many places the mains water and gas supplies are plastic pipes and may isolate the internal copper pipework from the ground. The pipework is also connected to a grounding rod ensuring that the entire plumbing system is fully earthed.

In the old days when water mains were still copper it was quite common practice to use a burried water main as the ground rod! a practice long since banned.

I never understand the logic behind not grounding a system. It's something that's not all that costly and only has to be done once. It just seems slightly ridiculous not to do it properly when you're wiring in the first place.

Slightly off topic but:

The ESB seems to make a big fuss about Neutralising supplies and doesn't like electrical contractors or members of the public to get involved with what it sees as a supply issue that only it should be involved with for safety reasons.

They have become much more serious about defining the limits of what's the homeowner's and what's theirs. Supplies now terminate on an isolation switch after the meter beyond which contractors can work. After the installation is complete the contractor must seal the cover on connection terminals at the switch with a lead tag and this is only supposed to be opened by the ESB or an electrical contractor. As far as I'm aware breaking the seal will potentially land you in court!

There is also some discussion about sealing the main distribution board in the house so that home owners effectively can't do DIY work.

I've seen a number of potentially leathal incidents caused by kitchen installers tampering with fusing arrangements on Diazed panels in particular. I remember removing a tampered with diazed fuse that was actually too hot to unscrew as a kitchen installer had skimped on hiring an electrician and simply branched a load of heavy kitchen equipment onto an old 20amp cooker circuit completely overloading it. He'd just tampered with and effectively by-passed the fuse to stop it blowing!!!

The circuit was designed to handle 20amps he'd hooked up:

10 X 13 amp sockets on a radial circuit.
1 X 2.5 KW oven
1 X 3 KW hob
1 X 3KW dishwasher
1 X 3KW microwave/combination oven
and even some recessed lighting!!!

The homeowner, a relation of mine, sued him for quite a substantial sum.

She'd got slightly concerned when she noticed that all these extra sockets were added yet there was no change to the fuse board. (and there was a slight smell of burn in the hallway when the cooker and dishwasher were on together)

There were reasons before the introduction of RCD:s. You can only get electrocuted if there is some kind of return path. This can be live to neutral (a danger that still exists) or live to earth. The latter danger can be removed by using an RCD or simply not providing an path to earth. In a dry room with no earthed metal work, you will have a hard time to get killed even by 230V. In a 100V system it'll probably be close to impossible. If you introduce earthed objects in the room, you introduce a lethal danger. (Unless you have a RCD to shut off the power.)

However, outdoors, in bathrooms and kitchens or industrial settings there is both plenty of earthed metal and/or water. Therefore, proper earthing is in these cases beneficial, even without RCD.

[This message has been edited by C-H (edited 01-27-2003).]

I don't like the Japanese idea of a grounding plug at all. Can't you just hear it now? "Well, we never bothered to attach that wire -- It always worked fine without it."

Paul:

In addition, some Japanese appliances are equipped with the standard "American" three pin earthed plug. The cursed adapters I mentioned in my previous post are supposed to be used when plugging into a two-pin outlet.

At least that's what this website recommends: http://www.interpower.com/icl/Japan.htm

I came across a few of the grounding adapters during my time in the States.

I do wonder how often people have just installed them without even realizing that the mounting screw/box might not be properly grounded in the first place.

As has been said above, if the box is already grounded, then it's a far better solution to replace the old receptacle with a 5-15 grounding type.

Presumably that's not an option in Japan, though.