Whether you’re an electrician or a handy homeowner, multimeters are excellent tools to have available. However, they can be intimidating to use unless you’ve had some training. In this article, we’ll look at how to test for both AC and DC voltage using a multimeter. Most importantly, you’ll learn how to do it safely to eliminate the risk of electrical shock.
How to Test AC Voltage with a Multimeter
If you’re using your multimeter around the house, you’ll likely be testing for AC voltage. It’s important to keep in mind that whether you’re using a digital multimeter or a manual one, the methods are the same. The only notable difference is that with a digital multimeter you push buttons and with a manual one you turn a knob. Here’s how to start testing.
• Remove your multimeter from its protective case and turn it on. Turn the mode switch to AC voltage.
• Turn the voltage setting so that it’s as high or higher than the voltage of the appliance you’re testing. To be safe, you can turn it all the way to the highest voltage.
• Plug the black probe of the multimeter into the slot marked common or COM.
• Plug the red probe into the other slot, usually marked with a V. It might also be marked with a V followed by various symbols.
• Place the end of the black probe against one side of what you’re measuring and the end of the red probe on the opposite side.
• Make sure that there is power running to whatever you’re trying to measure.
• Remove the red and black probes from the slots and turn off your multimeter.
That’s all there is to it. It’s not overly complicated, but it’s important to follow the above steps in addition to the safety tips below. You can use this method to test anything from a light switch to a circuit breaker to an outlet.
How to Test DC Voltage with a Multimeter
DC voltage is mostly found in cars, batteries, and car batteries. Here’s what you should know when using a multimeter with DC voltage.
• Connect your red and black probes following the same steps listed above for AC voltage.
• Turn the mode switch of the multimeter to DC rather than to AC.
• Turn the voltage selector knob or button to the highest voltage setting of 30 volts. You can keep it there or work your way down until you get close to the actual voltage of whatever you’re testing.
• Touch the black probe to the negative terminal or side of the battery you’re testing.
• Touch the red probe to the positive terminal or side of the battery you’re testing.
• Remove the red and black probes from their slots and turn off your multimeter.
Safety Tips when Using a Multimeter
Now that you know how to use a multimeter to check both DC and AC voltage, let’s look at some safety tips to always keep in mind.
• Do not touch the lead tips as this could result in a shock
• Do not touch the tips to each other
• Do not touch a tip to a metal surface
• Do not insert the test leads into the incorrect jacks
• Never test an AC main – leave this to the professionals
• Always wear safety goggles, gloves, long sleeves
• Ensure that the breaker box is easily and quickly accessible
• Turn off the breaker switch for most electrical work
• Ensure the area is well-lit and free of obstructions
Working with electricity of any sort is dangerous and should only be done when following the above safety protocols.
Schedule Your Electric Inspection
If you’re like most people, you’ll want to leave your electric work to professionals. Wolfe Electric is an Omaha and Lincoln based electric company with the knowledge, experience, and expertise to protect your home or business from faulty electrical wiring and add upgrades as needed.
Omaha – 402-731-1220
Lincoln – 402-464-4333