If you’ve ever looked closely at the prongs of a standard electrical plug, you may have noticed two small round holes near the tips. Most people never give them a second thought, yet those simple openings serve several thoughtful and practical purposes. In fact, they’re part of a design created decades ago to keep homes safer, make plugs more reliable, and improve how everyday devices are manufactured.
A More Secure, Stable Connection
The most important job of those holes is to help the plug stay firmly seated in the outlet. Inside many outlets, small metal bumps or ridges align with the holes when you insert the plug. These ridges “catch” the prongs just enough to prevent them from slipping out too easily.
A plug that stays put reduces the chance of:
- sparks forming from a loose connection
- heat buildup
- unexpected disconnection from a light, appliance, or charging device
