Light case vibration

[Computer_Commando]

If "L" and "N" are reversed on a single mains outlet, and monitor has internal fault, this will cause your situation.  This is the whole point of grounded outlets:  to protect you from this very situation.

Is it dangerous?  Is electrocution dangerous?  Touch the case with one hand while touching a "real ground" with the other and you complete the circuit.  BTW, >6ma through the heart will kill you.  CFCI's sense the current in the ground wire and and set to trip at 6ma.  No current is supposed to flow in the ground wire.  This is different from a circuit breaker which measures the current in the hot (L) wire.

What's the problem in grounding systems used in buildings ?

[2k_dummy]

Have you tried to measure the frequency of the vibration? I would almost bet that it is 50hz.  The 230V supply is probably creating a weak electromagnetic field that is being absorbed by case. In a grounded outlet, the induced electric field would have a path to ground, thus absorbing it, and preventing the case vibration. In a non grounded outlet, the only path would be through the neutral, which is not connected to the case, so it has no place to go.

Forgot: Its all just theory anyway.

[merlin_2]

Most vibrations are cause by,unblanced parts,fans <heatsink etc>harddrive.....bearing failure.......<worn>even the case not sitting square on a flat surface..

[Fed]

Can you fit an earth leakage outlet in place of the non-grounded one?
It will 'measure' the current flow in the active & neutral wires then trip if a predetermined level of inbalance is reached.
Either way, do something before you kill yourself.  

[Raptor]

Its static build up. The reason it vibrates when connected to an ungrounded outlet is because its using me as a ground instead. Well, that's what has been told to me.

Its not the monitor. It happens even with the monitor disconnected.

I think Dummy2K has got a good point.

[Fed]

Raptor, I think you need to work out if it's a mechanical vibration, an electrical 'tingle' (lol) or a static discharge.

Static will discharge all at once, (ZAP) and then it's gone.

[2k_dummy]

If you have one item with a metal frame or case plugged into a grounded outlet and other items with metal frame/case plugged into a non grounded outlet, you can fool the non grounded items into thinking they are. Use bonding (grounding) straps to bond all the frames/cases together. This will essentially put all of them on a grounded outlet.

[Raptor]

If you have one item with a metal frame or case plugged into a grounded outlet and other items with metal frame/case plugged into a non grounded outlet, you can fool the non grounded items into thinking they are. Use bonding (grounding) straps to bond all the frames/cases together. This will essentially put all of them on a grounded outlet.

Thanks Dummy. I had noticed that effect when I used a grounded power cable and connected the VGA cable from the ungrounded monitor. Electrity just chooses the easiest path.

Raptor, I think you need to work out if it's a mechanical vibration, an electrical 'tingle' (lol) or a static discharge.
 
Static will discharge all at once, (ZAP) and then it's gone.

How do you think a static discharge comes to existence? By building up electricity.

I thought you were an electrician.

[Fed]

How do you think a static discharge comes to existence? By building up electricity.

Static comes from external sources and has nothing to do with your electricity supply.
Rub a plastic pen with a piece of cloth and you will see that it can then pick up small pieces of paper. (Static).
A static charge can build up in your body, just the same as in the pen, and that charge is always trying to get to earth.
That is why you are advised to touch the earthed frame of your computer before carrying out any repairs.
Doing that will discharge your body's static charge to earth before it has a chance to discharge through any of your computer's components.

I thought you were an electrician.

I am, that is why you are getting quality answers.  

If your 'vibration' is continuous it is electrical leakage.
If your 'vibration' is just a 'zap' then it is static.
Have you established if you have a static problem or electrical leakage?