Using laptop power supply in Japan

[Cameron McCormack]

Hi people.

I want to use my laptop when I'm in Japan next week, and apparently
Japanese wall sockets in general don't have earth pins. The transformer
my laptop uses does have a ground pin. Searching some shops, I found
only plug adapters that accept 2-pin Australian plugs. A couple of
people suggested that I take a 3-pin Australian cable and cut off the
earth pin so I can then use the adapter. So I have done this, but
before I leave: is this safe? The earth pin would only be used if there
was a fault in my laptop, right?

Thanks,

Cameron

--
Cameron McCormack
| Web: http://mcc.id.au/
| ICQ: 26955922

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[Cameron McCormack]

Cameron, check the lead out - mine has a 3 pin plug but only the A & N go
into the little switch mode supply (via one of those 2 way plugs like those
used on double insulated radio cassette/CD players etc). If yours is like
this I would imagine that you are safe as the earth is not connected through
anyway.

There are 3 pins on the transformer, too.

Thanks,

Cameron

--
Cameron McCormack
| Web: http://mcc.id.au/
| ICQ: 26955922

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[Trevor Wilson]

Hi people.

I want to use my laptop when I'm in Japan next week, and apparently
Japanese wall sockets in general don't have earth pins. The transformer
my laptop uses does have a ground pin. Searching some shops, I found
only plug adapters that accept 2-pin Australian plugs. A couple of
people suggested that I take a 3-pin Australian cable and cut off the
earth pin so I can then use the adapter. So I have done this, but
before I leave: is this safe? The earth pin would only be used if there
was a fault in my laptop, right?

**Just use one of those adapter plugs. Your laptop and power supply are not
likely to be earthed anyway. Of more concern is the Voltage rating of the
power adapter. If your laptop was manufactured anytime in the last 10 years,
I doubt it will be a problem. Most cope with 100VAC (Japan) to 240VAC
without switching. Check the ratings on your power adapter.

BTW: Cutting the earth pin off will not allow the plug to fit into the
Japanese socket. They are fundamentally different. Use an adapter.

 

[Cameron McCormack]

Hi Trevor.

**Just use one of those adapter plugs. Your laptop and power supply are not
likely to be earthed anyway. Of more concern is the Voltage rating of the
power adapter. If your laptop was manufactured anytime in the last 10 years,
I doubt it will be a problem. Most cope with 100VAC (Japan) to 240VAC
without switching. Check the ratings on your power adapter.

BTW: Cutting the earth pin off will not allow the plug to fit into the
Japanese socket. They are fundamentally different. Use an adapter.

Cool ok. The power supply is dual voltage. The issue is that the
converter plug only converts two pin Australian to two pin Japanese. I
had to cut off the earth pin to use the adapter.

Cameron

--
Cameron McCormack
| Web: http://mcc.id.au/
| ICQ: 26955922

Replies by e-mail must include the current month name in subject line to
bypass spam filter.

 

[Rob]

Cameron, check the lead out - mine has a 3 pin plug but only the A & N go
into the little switch mode supply (via one of those 2 way plugs like those
used on double insulated radio cassette/CD players etc). If yours is like
this I would imagine that you are safe as the earth is not connected through
anyway.

I would not like to comment if it is connected through. I'd be careful as I
imagine that there may be added damage risks apart from personal safety if
you connect your laptop to other IT gear or equipment.I've seen high
impedance AC voltages on a laptop serial port damage the gear it was plugged
into.

See what some others think.

rob

 

[Roger Lascelles]

I have measured continuity from the power supply ground pin right through to
the exposed metal of the laptop on a number of laptops, so the ground wire
is not always unconnected. This was a few years ago, so things may have
changed. If I were buying a laptop, I'd specifically look for a two wire
mains lead type, because I like that freedom from ground - saves burning out
the laptop if you plug the com port into a faulty device, etc.

The switchmode power supply uses really good transformer insulation between
mains and low voltage windings, tested with high voltage during manufacture,
so I am quiite confident that I wouldn't get killed if a ground wire was
disconnected.

However, I might feel a slight tingle due to capacitive leakage currents, if
I lightly touch metal on the laptop with disconnected ground.

If I was going to Japan, I would run the laptop with no earth, but I'd be
sensible - sit on the bed or sit on a chair with shoes on, not running it in
the bathroom or outside on the grass.

Roger

 

[Franc Zabkar]

I want to use my laptop when I'm in Japan next week, and apparently
Japanese wall sockets in general don't have earth pins. The transformer
my laptop uses does have a ground pin. Searching some shops, I found
only plug adapters that accept 2-pin Australian plugs. A couple of
people suggested that I take a 3-pin Australian cable and cut off the
earth pin so I can then use the adapter. So I have done this, but
before I leave: is this safe? The earth pin would only be used if there
was a fault in my laptop, right?

You will probably find there is a small capacitor between each of the
active and neutral pins and the ground pin. When the earth pin is
defeated, the earth reference of your laptop floats to a potential of
half the mains voltage. This means that any metal parts are
potentially "live", although the tingle you receive, if any, will be
exceedingly mild, if at all noticeable. You may draw a slight spark
when you plug in an external monitor, or some other earthed accessory.


- Franc Zabkar

 

[swanny]

I have measured continuity from the power supply ground pin right through to
the exposed metal of the laptop on a number of laptops, so the ground wire
is not always unconnected. This was a few years ago, so things may have
changed. If I were buying a laptop, I'd specifically look for a two wire
mains lead type, because I like that freedom from ground - saves burning out
the laptop if you plug the com port into a faulty device, etc.

The switchmode power supply uses really good transformer insulation between
mains and low voltage windings, tested with high voltage during manufacture,
so I am quiite confident that I wouldn't get killed if a ground wire was
disconnected.

However, I might feel a slight tingle due to capacitive leakage currents, if
I lightly touch metal on the laptop with disconnected ground.

If I was going to Japan, I would run the laptop with no earth, but I'd be
sensible - sit on the bed or sit on a chair with shoes on, not running it in
the bathroom or outside on the grass.

Roger

Or use a Japanese plug with an earth pin. I think the earth pin is a
round pin below the two flat pins.