For most contractors, especially electrical contractors, the difference is a known. But for most home users, they don’t even realize there is a difference. I was recently reminded of this as we were moving buildings and we started some cleaning up. We were using a Festool Dust Extractor as a vacuum (yes, that’s a fancy name for a vacuum) and it didn’t work in the outlet I originally wanted to use. So, for those that don’t know how to tell the difference, here it is.
On the left, we have a 15A outlet. I did my very best ASCII art (keeping with the Geek theme, it seemed appropriate). On the right, we have a 20A outlet. The horizontal line should have really been touching the vertical line, but that’s basically what you’re looking for. A 20A plug has one horizontal and one vertical prong along with the round grounding plug. Older houses typically have 15A outlets and very few if any 20A. Newer construction should have 20A much more readily available.
Most wiring will handle the 20A just fine, but since it isn’t always the case you’ll want to have a certified electrician check it before you replace an outlet with a higher rated receptacle. But, if you get a tool that requires a 20 amp circuit, now you’ll know what to look for.
Edited to reflect 15 and 20 instead of 10 and 15. Thanks for the heads up, Mike.
