My Macbook Pro gives electric shocks. How can i measure it?

I'm getting electric shocks/strong tingling sensation with my Macbook Pro whenever the power chord is plugged. It happens all the time, anywhere, and is unrelated to wearing shoes or not. It's disturbing enough to prevent normal use, and really makes me wonder if it is a health hazard (what's the limit again for DC, 30 milliamps before you're history?).

I tried measuring it with a multimeter. I got some readings at 18V (quite typical of a charger voltage).

I'm unhappy with this, and the net is littered with people complaining about this same problem.

How can I properly measure the voltage? What do regulations say?

you already answered your first question. as for your second that depends on what regulation you are talking about. I could tell you what is causing it but you didnt ask that