Electrical

Multimeter Basics - Testing an Outlet

Learn how to safely test a standard 120V household outlet using a multimeter. This step-by-step guide walks you through proper multimeter settings, lead placement, and voltage checks between hot, neutral, and ground to ensure your receptacle is wired and functioning correctly. Perfect for HVAC, maintenance, or DIY troubleshooting.
Best Practices
Diagnostic
Hard Skills
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Transcript

 Okay, let's go over some troubleshooting tips and how to use your multimeter when you're testing a receptacle. A common household residential outlet that provides 120 volts. So of course we get our meter and you turn it from off to voltage and you wanna make sure that it's on. Alternating current, which is the voltage with the sine wave. Next thing you wanna do is rest the multimeter somewhere that you can easily see it while you put the leads into the slots on the receptacle. And this particular case, it's here now. A couple things to consider when you're using the multimeter, and let's go over the receptacle itself for a moment. This half moon slot is ground. The smaller slot is the hot wire, and the larger slot is the neutral, and it's supposed to be anyway. So the first thing you do is you always put this lead in to the neutral slot. Just in case anything arcs, you have the outlet and your hand connected to neutral. Same thing with the ground. So there should be no voltage on the neutral, and there should be no voltage on the ground, and you can test that. But most importantly, what we wanna do first is make sure that this goes into the neutral slot. The red lead goes into the smaller slot, which is the hot wire, which is typically most often the black wire, and then the half moon is the ground, which is commonly a green wire. Now that the leads are correctly in the receptacle, the multimeter is in the right setting. It's on AC voltage. The decimal point is in the correct place. We can see that we have 125 volts, and this receptacle is providing the correct voltage if you'd like, to make sure the ground is working. All you have to do is take both leads out. Start with the red one going into the ground, and the black one in the hot wire. And once again, you should have 125 volts, which is exactly what this is providing. So now we have the same voltage. Between the large slot and the small slot, the black and the white wire, the hot and neutral as we do the hot wire and the ground, and that's how you test the receptacle voltage with a multimeter.