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

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Discussion Overview

The discussion revolves around the issue of experiencing electric shocks when connecting devices like digital cameras or camcorders to a TV with a 2-pin plug. Participants explore potential causes and solutions related to grounding, wiring issues, and the safety of electrical connections in a rented house.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant reports experiencing electric shocks when touching their camera connected to a TV with a 2-pin plug, suggesting a need for a ground return for the TV power.
  • Another participant proposes that the neutral line may not be well grounded at the breaker panel and inquires about the living situation (house or apartment) and whether the participant has a 3-prong socket tester.
  • A participant shares a link to a 3-prong tester and asks if there are alternative methods to check neutral grounding without the tester.
  • One suggestion involves using a digital voltmeter (DVM) to measure AC voltage between neutral and ground in various wall sockets, noting that higher voltage readings may occur farther from the breaker panel or under load.
  • Concerns are raised about the possibility of reversed wiring in the socket, with a suggestion to verify the proper insertion of the TV plug and check for old or worn sockets that may allow incorrect plug orientation.
  • Another participant discusses the historical context of electrical safety, noting that modern equipment should only produce a mild sensation rather than a dangerous shock, contrasting it with older equipment designs.
  • A participant reports measuring voltages between AC and neutral, with readings of 3V in some locations and 50V in others, expressing concern that 50V is too high.
  • Further discussion indicates that the same shock sensation occurs when using a multi-way mains splitter, and one participant describes feeling a mild shock when touching screws on their laptop while grounded.
  • Participants note differences in plug designs, mentioning that some plugs have a larger pin for neutral and line, while others do not.

Areas of Agreement / Disagreement

Participants express various hypotheses regarding the cause of the electric shocks, including potential grounding issues and wiring reversals, but no consensus is reached on the exact cause or solution. Multiple competing views and concerns remain unresolved.

Contextual Notes

Limitations include the lack of definitive measurements or tests confirming the state of grounding and wiring, as well as the dependence on individual experiences and equipment variations.

likephysics
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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.
 
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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?
 
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.
 
Last edited by a moderator:
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.
 
pantaz said:
I've seen old, worn sockets that allow plugs to be inserted wrong.

:bugeye: Yoiks!
 
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.)
 
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berkeman said:
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.
 
sophiecentaur said:
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.
 

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