According to the NEMA Standards Publication, "Hole in flat blade is optional, and is intended for manufacturing purposes only. ... Other Incidental Uses Of The Holes In Electrical Plug Prongs.

Replacing a plug on an electrical cord is pretty easy, but you might want to check the condition of the cord; if it is cracked or damaged, you must replace it to avoid a shock hazard.

It began as just one of those niggling everyday frustrations. But a design student's determination to end the 64-year reign of the unwieldy three-pin electrical plug has won him an international ...