How to Test an Outlet with a Multimeter

Many of the projects that we’ve showcased on this blog require you to use a multimeter to test outlets before you get on with doing the rest of the work. In the interest of electrical safety we wanted to give this task some individual attention so that you’d know exactly how to do the job safely.

Testing outlets is also useful for knowing whether you’ve got a problem that requires you to call out a professional electrician. Sometimes outlets go inexplicably dead. You can verify whether or not the problem is with your appliance or whether it’s with your outlet by using this simple test.

First, look at your outlet. You’ll notice that it has a long side, a short side, and a round side. You might also notice that it looks like a very frightened little face. This is either coincidence or an attempt to discourage kids from sticking their fingers into it.

Before you begin you need to understand the outlet itself. The long side of the outlet is the “neutral” side. The short side is the “hot conductor.” and the round side is the “grounding conductor.”

Plugs are built so that you always put them in the correct way every time you use the outlet. It’s impossible to reverse the plug, which is good, because an absent minded mistake could be costly.

Multimeters, however, don’t plug into the outlet in order to test them (though there are plug-in electrical testers that will get the job done without reading voltage). Instead, they come with 2 test prongs. If you don’t put the right prong into the right part of the plug then you could endanger yourself.

You also have to put the prongs into the plug in the right order.

Start with the red prong. Place it inside of the long side of the plug. This always goes first!

Then, add the black testing prong to the short side of the plug.

Now you can get the reading from your multi-meter. A normal plug will register around 120 volts (water heater plugs may go as high as 240).

If your plug is under-performing or not-performing at all then you might need to call an electrician. Of course, if you’re tackling a DIY project a plug with no power means that it’s safe to proceed.

If one of your plugs isn’t working and you don’t know why, call us! We tackle tough electrical problems all over the Raleigh-Durham area and we can help you, too.

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