Reply to post: Re: and things like chargers tend to have plastic prongs with metal tops.

Re: and things like chargers tend to have plastic prongs with metal tops.

The video that you link to shows a plug being inserted upside down into the earth socket so that the shutters on the the other two sockets are opened. If the earth pin on the plug was triangular in cross section (or any other shape where the two sides are not parallel), this would not be possible.