13A sockets for charging electric cars

[Crackle]

My 3kW KB fan heater heats up the twin 13A sockets I fitted around the museum. http://www.kbmuseum.org.uk/kb_appliances.htm
So no, modern sockets do not take happily to the full 13 A load.
I kept the plug with the non shielded pins on it deliberately, but believe it is the sockets themselves which get hot.

Mike