Last Updated on September 14, 2023 by Dave Farquhar
If your plug breaks and you need to replace it, you can get replacement three prong plugs at a hardware store. But it usually comes bare, without any instructions. So, I’ll write some for you. Here’s a three prong plug wiring diagram if you need it.
3-prong plug wiring diagram
What the inside of your plug looks like will vary. Most of the ones I’ve seen have a block inside with three screws, but how they mount the screws won’t always be the same. The important thing is following the color coding. In the United States, the color coding should always be the same.
In the United States, the black wire goes to the gold screw, the white wire goes to the silver screw, and the green wire goes to the green screw. If you reverse the green screw with one of the others, you’ll blow breakers and the item won’t work at all. If you reverse the gold and silver screws, your item will probably still work. It’s a slight safety hazard, so you want to get it right.
In US AC wiring, the black wire is hot, the white wire is common or neutral (the two terms mean the same thing), and green is ground.
Wiring up your replacement 3-prong plug
It’s best if you tie a knot in your cord near the end, just after it enters into the plug. That way the cord can’t pull out of the plug.
Strip the wire back about 3/4 inch. Here’s a trick for doing that without damaging the wire. Then twist the wire strands and bend it into a U-shaped loop. Hook the loop onto the appropriate screw, then tighten the screw. This gives a firm connection that won’t fall off and short against another wire.
Position the knot just after the opening, then close up the plug. You’ve wired up your replacement 3-prong plug.
David Farquhar is a computer security professional, entrepreneur, and author. He started his career as a part-time computer technician in 1994, worked his way up to system administrator by 1997, and has specialized in vulnerability management since 2013. He invests in real estate on the side and his hobbies include O gauge trains, baseball cards, and retro computers and video games. A University of Missouri graduate, he holds CISSP and Security+ certifications. He lives in St. Louis with his family.