Not all outlet holes are the same, and there's a reason for that. The shapes (vertical slots, round holes, T-slots, etc.) correspond to specific electrical functions and safety features. Take the ...

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 ...

Hand holding a polarized power plug near a wall outlet with other devices already connected - Jannhuizenga/Getty Images If you've ever looked closely at an electrical plug, you've likely noticed that ...