Laptop lid is tingling on touch

[xoxaunc]

Facts:

Thinkbook 14 G4 AIP - laptop A

Thinkbook 14G4 AIP supplied power adaptor - adaptor A (65w usb-c, fake plastic ground for UK socket) is what is supplied with laptop A

Lenovo T series power adaptor - adaptor B from other laptop (65watts usb-c real ground)

1. When using a socket A and power adaptor A, laptop A metal lid is giving microshock - tingling sensation.

2. When using socket B or C and power adaptor A, laptop A metal lid is not shocking anymore.

3. When using socket A and power adaptor B, laptop A metal id is not shocking anymore.

So the question is: who is the -------? The socket A, the adaptor A or the laptop A? Why socket A is unwilling to be friends with adaptor A. The socket passed socket tester..

 

[Lucien Nunes]

The tingle you can feel is called 'touch leakage' and is a very tiny current, often a small fraction of a milliamp. From a proper safety-approved adaptor it is harmless and just an unfortunate side-effect of the design, which is intended to be equally safe and proof against causing radio interference when used with non-earthed sockets in other countries.

I believe you are saying that adaptor A has no connection to mains earth, because it has a 'plastic earth pin' instead of a metal one (properly called an ISOD). Adaptor B appears to have a functional earth connection to discharge the leakage.

If adaptor A has no connection to earth, the condition of the earthing at socket A, versus sockets B and C, cannot influence whether you can feel touch leakage or not. Therefore, the difference in what you feel must be due to some other factor. Because the leakage current is so small, what you stand the laptop on, what metal objects you stand near, etc. can alter the level of sensation. So it might not strictly be the choice of sockets A / B / C that makes the difference.

The presence of the functional earth in adaptor B would be expected to eliminate the leakage tingle, so long as the earthing in the socket is OK. The fact that it does so implies the earthing is OK at socket A, although it is not a thorough test and a proper measurement would be needed to confirm.

From the information given, nothing here seems unusual to me. My main concern would be whether adaptor A is a genuine safety-approved product and not a low quality counterfeit unit that does not meet the required specifications for leakage and insulation quality. If it came with the laptop at initial purchase it's probably fine. A 'PAT test' or in-service safety test would at least confirm whether the amount of leakage it creates is normal.

I spend a lot of time connecting laptops together and to earthed systems (sometimes dozens of laptops) and get used to some adaptors causing touch leakage and others not. Even different models of genuine Apple chargers vary in this regard.