Have you ever wondered why some electrical plugs have holes in them? Well, the real reason is not as mind-blowing as you might think.
Back in 1913, a scientist and inventor by the name of Harvey Hubbell patented the United States electrical plug socket. He was the original inventor of the two holes in US plugs people are so familiar with today. Those original two holes were designed to prevent the plug from falling out of the socket. But, today, the sockets are a completely different design, relying on friction to prevent the plug from falling out – which renders those holes useless.
Another myth is that those two holes are there in order to allow someone to lock a plug with a plug lock, preventing someone from using a particular device or appliance. But... plug lucks were not invented until the late 1950s.
The last misconception was to save metal during manufacturing, but no such claims have ever been proven.
The real reason as to why plugs have those two holes in them is quite simply because it's the done thing. They don't add any value or hold any purpose whatsoever. You never think twice about those two holes, but if they were missing, the plug would still work perfectly fine, it will just look odd to the user.
Take a look at the video below by YouTube channel, Silver Cymbal, on Why Do Electrical Plugs Have Holes In Them?