Electric shocks from Mac Mini: weird issue

[Speedy]

My grandparents got a Mac Mini. They recently moved to a new house, without electrical grounding. It's also not allowed to change the wires, as it's a rental house.

Now the issue is, the Mac Mini is connected to a power outlet through a multi-socket extension cord. When the power switch of the extension cord is turned on, I feel electrical shocks when I touch the Mini, but also when I touch the aluminum keyboard. To make it even worse, when using a screwdriver with a lamp (the ones used to find power), the light turns on and I get an electrical shock from that screwdriver. However other people don't feel shocks and the light of the screwdriver doesn't lit when they use it. It appears to be only happening to me.

Now my grandpa has connected the ground connector of the power outlet to an unpainted part of the radiator. So it's actually grounded, but I still feel the shocks. This never happened at the previous house.

Does anyone have an idea on what to try next? I also need to say that I sit in a electrical wheelchair with rubber tires. Don't know if that has anything to do with it...

 

[Speedy]

I am pretty sure that actually you are shocking the mac mini! For some reason you are charging up with static electricity and so you will discharge yourself and feel a shock when you touch something which is grounded. Since you are in a wheelchair with rubber tyres it is not possible for you to be shocked by an external source (unless the voltage is high enough). You can check this by going about your daily business and then touch something else (the kitchen sink, if it is metal, or another person) and see if you have a shock.

The static may be related to your wheelchair and the floor in the new house (is it plastic vinyl?). Have a look at this website, it suggests some ideas to stop it happening:

http://www.apparelyzed.com/electricshock.html

Hope this helps!

The floor is made of wood. But the weird thing is, that this doesn't happen to me when touching metal devices in my own home (which are correctly grounded 'as it should').

But I was thinking of the following: The seat of my wheelchair is also wired with copper wires. Now it might be possible that the chassis of the wheelchair is used as a ground to protect the person from getting shocks from the wheelchair itself, as the tires cause isolation. And that might have a much lower electrical resistance as the grounding of the wires (that are connected to a metal part of the radiator), therefore leading the electricity to me instead of the radiator. Could this be a cause, or am I just talking nonsense?

 

[Speedy]

Isn't the wiring illegal to have like that?

Don't think so, as water pipes where used in the old days to ground the electrical system...

UPDATE:
Today I found a power socket with ground leads (where correctly grounded), and I've plugged the Mini into that socket. However I still felt a shock, but this time much stronger. There where sparks jumping from the keyboard...
Then I've put isolation tape on the aluminum part of the Mini, and then I didn't felt any shocks. But when I touched the Mighty Mouse with one hand and then touched the Mini with the oher hand, I felt a very powerful electric shock from the Mini. There where even sparks appearing from the isolation tape.

So it has got something to do with my wheelchair in that house. My grandpa informed me that the floor is isolated, but the top layer is made of wood. Could that have something to do with it? I personally don't think so, as my tires are also isolated.