Surface book charger safety

To my suprise I have measured an AC voltage of almost 150 Volt on the surface book case when either the charger or the surface dock are connected for charging both original Microsoft products. I have also measured an AC voltage of almost 150 Volt on the earth of the surface dock connector the part which is plugged into the surface book and which is supposed to have 15 DC voltage. Also on some of the pins of the surface book charger, I have measured almost 150 AC Volt which should have at most 15 V DC.


Now, it is clear that the 150 AC volt which I have measured on the case are originating from the surface book chargers.

What I don't understand is how a connector which should have at most 15 V DC can provide a life-threatening 150 V AC? By the way, if plug in the charger into the 230 V socket turned around by 180°, I measure about 50 V AC.


Since I obtained the same result from 2 power supplies the standard charger and the surface book dock, this seems to be a design error: somehow the design of the surface book chargers allows for a high AC voltage going onto the low voltage DC part....


Has anyone made the same observations?