What Are The Holes In Electrical Plug Prongs For?
The US uses two standard electrical plug types: Plug Type A and Plug Type B. Both have two parallel pins for power, while the latter has an additional grounding pin for safety. But if you look closely at both, you'll notice that the two parallel power pins have one hole in each. Many say that the reason these holes exist is to help the plug stay attached to a wall socket. After all, it does make sense for a plug to have an attachment point to prevent it from being accidentally unplugged. However, if you disassemble most outlets (don't do this while it's powered) or peek into one of its active holes (please don't put anything in it), you'll see they do not have a bump that will hold a plug in place. Instead, the prongs are held purely by friction. Thankfully, we can get the answer directly from NEMA, or the National Electrical Manufacturers Association — the industry group that sets the technical standards for America's electrical equipment. According to...