Ground 2-Pin Plug: Prevent Electric Shock with TV & Laptop

[likephysics]

I get an electric shock whenever I connect my digital camera or camcorder to my TV. The shock occurs whenever I touch the camera.
The TV plug has only 2 pins.
So my first thought is to provide a ground return for the TV power.
The shock hazard occurs only with the 2 pin plug equipments like TV, laptop adapter etc.
When I touch a tester to the headphone socket of my laptop, the tester lights up.

 

[berkeman]

Sounds like your neutral line is not well grounded at your breaker panel. Are you in a house or an apartment? If a house or condo, do you rent or own?

Do you have a 3-prong socket tester (the little ones with 3 neon lights). Does it show "normal" for the sockets, or does it show a fault?

 

[likephysics]

I'm living in a rented house.

Is this the 3 prong tester - http://cgi.ebay.com/ws/eBayISAPI.dll?VISuperSize&item=360273547780

Any way to check the neutral grounding without this tester?

 

[berkeman]

This tester:

[URL]http://www.ibuonline.com/storage/product/9b8/799/a49/e1a8bdadb9441ee1649ae2f.jpg[/URL]

You can test your neutral with a DVM. Carefully measure the AC voltage between Neutral and ground in several wall sockets in the house. You should not get much of a voltage. You will get more voltage farther from the breaker panel, and when there are large loads on the line.

 

[pantaz]

The tester shown above will also show if the wiring is reversed. Assuming the TV's plug is polarized (one prong is wider than the other), verify that it is properly inserted in the socket. I've seen old, worn sockets that allow plugs to be inserted wrong.

 

[berkeman]

I've seen old, worn sockets that allow plugs to be inserted wrong.

Yoiks!

 

[sophiecentaur]

Sounds to me that L and N could be reversed in the socket. Does the same thing happen if you use a multi way mains splitter and operate all devices from one socket? Even if it's wrongly wired, they should all be the same way round. It's possible but unlikely that the plug on the TV is wrongly wired but you could always cut it off and replace it. (the only way to find out about it would be to destroy it, unfortunately as it is almost sure to be the moulded type)

But, on modern equipment, the only shock you should expect would be a tiny 'scratchy' sensation; not lethal or even uncomfortable. In the days of TV, there was no transformer and no exposed metal parts. The chassis was connected to N and that could kill you if the plug was wired incorrectly (red/brown/white/black ? - you name it) and you could get your hand inside. The only way to connect to other equipment was by ac coupling (RF in via capacitors or balanced audio out via a transformer.)

 

[likephysics]

You can test your neutral with a DVM. Carefully measure the AC voltage between Neutral and ground in several wall sockets in the house. You should not get much of a voltage. You will get more voltage farther from the breaker panel, and when there are large loads on the line.

I measured the Voltage between AC and neutral. In some places it's around 3V and in others it's 50V!
I think 50V is way too high.

 

[likephysics]

Sounds to me that L and N could be reversed in the socket. Does the same thing happen if you use a multi way mains splitter and operate all devices from one socket? Even if it's wrongly wired, they should all be the same way round. It's possible but unlikely that the plug on the TV is wrongly wired but you could always cut it off and replace it. (the only way to find out about it would be to destroy it, unfortunately as it is almost sure to be the moulded type)

Yes, same thing with multi-way mains splitter.
I get a mild shock(if I am grounded) when I touch any screws on my laptop(IBM T42).
While holding the laptop, if I don't touch the screws and touch someone who is grounded, I can feel the current(skin effect I think, bcoz of the SMPS switching frequency). The adapter plug does not have a different pin for Neutral and Line. In some equipments one is slightly larger at the front.
My other laptop-Compaq, has a 3 pin plug. I can feel the current when I touch someone who is grounded.