Why is there electricity flowing through my VGA and other connectors?

I am using Windows 7 on a Sony VAIO laptop. When I connected my PC to the charger, I felt a little electric shock when I touched the VGA and other connectors. I tested with a current detector and found that I was indeed correct: there is current flowing through these connectors. I checked my other laptops but it is not the case with other laptops.

Can anyone help in answering the following questions:

Why is there current flowing?
What is the negative impact on my laptop?

Sumit Gupta

Posted 2011-08-17T18:05:48.933

Reputation: 395

4Did you test the other laptops in the same outlet? this sounds like a grounding issue, either the outlet or something in the laptop is not properly grounded. – MaQleod – 2011-08-17T18:10:35.077

Agreeing with @MaQleod, also check this laptop in a different outlet, preferably in another building (in case there's a problem with your building's wiring). – CarlF – 2011-08-17T18:14:15.103

Yes, I am checking other laptops in same conditions. Only one of the laptop is showing current in VGA ports. – Sumit Gupta – 2011-08-17T18:14:50.500

@CarlF If the PSU is 'double insulated' (no earth/ground bonding) then it is unlikely to be a building wiring fault unless there is a high voltage fault at the local substation - but then lightbulbs would be popping out of the sockets and all other electrical appliances in the fault zone would be freaking out/smoking/sparking etc. – Linker3000 – 2011-08-17T18:52:59.360

Answers

It sounds like your laptop has issues with a ground, since the voltage on the VGA connector is floating high. You should not have gotten an electric shock, since nominal VGA signaling occurs at 0V and 0.7V. If possible, open the laptop, and try to see if any components are electrically shorted to the laptop chassis and/or other connectors.

If you only experience the shock when the charger is connected to the laptop, then you should stop using the charger immediately and get a new one. Check the charger itself for ground faults. If you are using an ungrounded charger, there may be an electrical fault in the actual socket. Start with the charger, and work from there.

Again, there is no voltage in the laptop which is high enough to shock you. I have not seen any laptop chargers provide a DC output higher then 18.5V. Look into the charger or any short circuits (either in the laptop or charger), but again, since you're getting shocked, ensure that your charger is not the problem.

Breakthrough

Posted 2011-08-17T18:05:48.933

Reputation: 32 927

2I will take my laptop to the service center tomorrow. – Sumit Gupta – 2011-08-17T18:22:58.730

@iSumitG does this only happen when the laptop is plugged in, or on battery power as well? – Breakthrough – 2011-08-17T18:29:37.793

Only when the charger is plugged in. When on battery, there is no current in VGA port. – Sumit Gupta – 2011-08-17T18:30:23.420

4@iSumitG the laptop is not the problem. There is an issue with your charger, I would highly recommend that you don't use it for the time being. Is it a two-prong or three-prong charger? – Breakthrough – 2011-08-17T18:36:12.713

It is a two-pin charger. – Sumit Gupta – 2011-08-17T18:37:55.130

3Get a new charger for the laptop, and stop using that one immediately. If possible, try to get a new one with three prongs, so it is grounded. Without any further information, I can only tell you that there is an issue either with your charger, or your mains outlet. – Breakthrough – 2011-08-17T18:42:09.707

The immediately cannot be stressed any further! – surfasb – 2011-08-18T05:55:02.067

You should not be getting shocks (other than maybe feet-on-the-carpet static-electricity shocks in dry winter air) from computer equipment. All computer equipment must be either "double insulated" or grounded (or sometimes both).

A laptop should be protected by it's charger. The charger should not cause the laptop to have a "charge" -- a voltage potential between bare metal parts and ground -- and, ideally, should have a 3-prong plug that grounds the laptop. (And of course one should never use a "suicide plug" to defeat the 3-prong ground.) If the charger is "putting a charge" on the laptop then then charger is defective and should be discarded yesterday.

But note that it's also possible for another (defective) device -- eg, a video monitor -- to produce voltage potential that is applied to the laptop via the device's connection. Any device that is plugged into AC power can do this if defective.

Daniel R Hicks

Posted 2011-08-17T18:05:48.933

Reputation: 5 783