Last Updated on March 10, 2021 by Dave Farquhar
While an outlet or electrical appliance will work if you wire it in reverse, it’s a safety issue if you get it wrong. So which side of an outlet is hot? Here’s how to remember.
Which side of the outlet is hot
In AC electrical wiring, at least in the United States, the hot wire is black. The neutral or common wire is white. The terminals on your outlets are color-coded as well. The neutral side is nickel-plated, what we call a white metal. It’s more silver than white, but it’s closer to white than black. The hot side is brass plated. And traditionally, black and gold look good together. Remember, white to white and black to gold when you’re looking at the outlet from the wiring side.
From the plug side, I can’t tell you left or right because I don’t know if your outlets are mounted with the ground plug on the top or the bottom. That’s why the slots are different sizes.
Looking at the receptacle itself, the hot side is the side of the outlet the thinner prong plugs into. The thin prong is the hot wire, and the thick prong is the neutral wire. If I tell you to remember the thin prong is hot I’m violating every HR policy in the country, but you’ll remember it now.
And that’s how you can remember which side of the outlet is hot. I used to have two coworkers who had an inappropriate workplace relationship. When they openly committed an HR violation, which typically was at least twice a day, I’d bellow, “Gold star!” So just remember Dave’s gold stars for HR violations.
Telling you to remember the thin prong is hot is an HR violation, so Dave the Office Saint had to give himself a gold star. And the gold star is also hot. Is that another gold star?
What does the neutral side do?
The neutral side’s job is to carry electricity back to the panel, where it can run to ground. Normally that side can’t shock you. If it does, something’s miswired.
Why we started mounting outlets upside down
In older houses, the ground prong is on the bottom of the outlet. In the 1990s, we started mounting outlets with the ground prong at the top. That’s for safety. Outlets look better to human eyes mounted with the ground prong at the bottom, because it looks more human-like. But if your plug isn’t plugged all the way in and something falls on it, it’s much better for it to land on the ground plug than for it to land on the two plugs carrying current.
When I install an outlet, I install it with the ground plug facing up, because my day job is literally telling people how to play it safe with their computers. An inspector won’t fail me based on the direction it’s facing, but I default to playing it safe. The same guy who had that inappropriate office relationship had a decorative light that he couldn’t plug into an outlet his builder had installed “upside down.” I told him he could spin it around so his light would face right side up.
So that’s why I can’t tell you definitively if it’s the prong on the left side or the right side that’s the hot side of your outlet. It depends on when the house was built or remodeled.
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.