close up of Type A plug prongs - Gabriel Lopez/Shutterstock If you've ever stared at the holes in an electrical plug and wondered why they exist, you're not alone. Like an industrial-age kōan, the ...

In 1904, back when Thomas Edison was alive and Tesla was just his rival's last name, Harvey Hubbell patented the electric plug. Before that, electrical connections were hardwired. Hubbell's plug was ...

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 ...

We use plugs every day, but most of us don't spend a lot of time thinking about them. We know that there are various electrical plug types, even if we're not familiar with the ins and outs of all of ...