It seems that a safety issue still exists in connection with three-pin plug sockets. It used to be thought that equipping such sockets with shutters and putting in place blank plugs would be enough to stop children from electrocuting themselves.
The latest edition of E&T magazine draws attention, however, to the possibility of a child removing eg a blank and replacing the longest prong, rotated through 180degrees, into its hole. This would potentially allow lethal access to current from the other two apertures.
Today’s invention is one way to deal with this. A plastic shelf, shown in orange, is secured to the wall socket via the screws holding the front plate. This protrudes from the plate so that it’s impossible to get the long prong of a plug or blank anywhere near its hole in anything other than the correct orientation.
This is perhaps another example of why we need to educate people to think outside the narrow confines of being an ‘electrical’ or a ‘mechanical’ Engineer.