How to Measure Amps with a Multimeter (2-Part Guide)

Working on an electrical project, you may need to check the amperage or how much power is flowing through the circuit. You also need to measure amps to detect whether anything is drawing more energy than it should.

Measuring current amperage might be beneficial when attempting to discover if a component in your car is draining the battery.

In general, here is how to measure volt-amps with a multimeter. The following steps will help you out. 

  • Turn off the circuit’s electricity.
  • Remove the red wire from the power source
  • If needed, strip the wire ends.
  • Wrap the multimeter’s positive probe with the positive wire.
  • Power the circuit by connecting the black multimeter probe to the last wire.
  • While reading the meter, leave the devices in place for roughly a minute.

Fortunately, measuring amps is simple if you know the basic multimeter test and practice caution near electrical components.

Allow me to guide you in learning how to measure amps with a multimeter. 

Safety Precautions

socket and multimeter

You must be cautious whether you use a basic multimeter or a digital multimeter. When obtaining electrical measurements, each application with measuring amps poses possible safety dangers that must be considered. Before utilizing any electrical test equipment, individuals should always read the user’s handbook. It is pertinent to learn about proper operating techniques, safety measures, and limitations. (1)

Wear strong rubber gloves, avoid working near water or metal surfaces, and avoid touching exposed wires with your bare hands. It’s also good to have someone nearby. A person who can help you or call for help if you suffer an electrical shock.

Setting Up the Multimeter

setting up your multimeter

#1. Find out how many amps volts your battery or breaker can handle on the nameplate.

Confirm that your multimeter fits the number of amps flowing through the circuit before connecting it to it. The estimated maximum amps of most power sources in the nameplate are displayed. At the back of the instrument or in the instruction manual you can find the total amps of the multimeter leads. You might also see how high the scale goes. Do not attempt to test currents higher than the largest scale setting. 

#2. Use plug-in clamps if your multimeter leads are not rated high enough for the circuit. 

testing battery and wires with multimeter

Feed the wires into the multimeter and connect to the circuit. Do it in the same manner you would on the multimeter clamps. Wrap the clamp around the live or hot wire. It usually is black, red, blue, or another color other than white or green. Unlike using a multimeter, a clamp will not become a part of the circuit.

#3. Insert the black probes into the multimeter’s “COM” port.

Even when using a clamp attachment, your multimeter should include a red and a black probe. The probe will also have a tip on one end to hook into the meter. The black probe, which represents a negative wire, should always be inserted into the COM socket. “COM” means “common,” and if the port isn’t labeled with it, you can get a negative sign instead.

If your wires contain prongs, you’ll need to keep them in place when measuring current. You can free up your hands by attaching them to the circuit if they have clamps. However, both types of probes will connect to the meter in the same way.

#4. Insert the red probe into the “A” socket.

You may see two sockets with the “A,” one marked “A” or “10A,” and one marked “mA .”The “A” or “10A” socket is meant to test current up to 10 amps, while the “mA” socket tests milli-amps up to roughly 300 mA. When you’re unsure which to use, go with the higher “A” or “10A” option to avoid overloading the meter.

#5. On the meter, you may select AC or DC voltage.

If your meter is built to test AC or DC circuits solely, you’ll need to choose which one you’re trying. If you’re still not sure, check the label on your power supply again. It should be mentioned beside the voltage. Direct current (DC) is employed in battery-powered vehicles and gadgets, while alternating current (AC) is typically used in home appliances and electric motors.

#6. Set the scale to a higher amps volts level as you’re measuring.

Once you’ve calculated the highest currents to be tested, locate a lever on your meter. Turn it slightly higher than that figure. If you want to be cautious, turn the dial to the maximum. But if the voltage you’re measuring is too weak, you cannot obtain a reading. You’ll need to lower the scale and retake the task if this happens.

How to Measure Volt Amps with a Multimeter

multimeter device tool

#1. Turn off the circuit’s electricity.

If your circuit is battery-powered, disconnect the negative lead from the battery. If you must shut off the electricity at a breaker, turn off the switch, then detach the opposing line. Do not connect the meter to the circuit when the electricity is switched on.

#2. Remove the red wire from the power source.

To measure the current flows across a circuit, connect the multimeter to complete the course. To begin, turn off the power to the circuit, then disconnect the positive wire (red) from the power source. (2)

You may need to cut the wire with wire cutters to break the circuit. See if there’s a cap where the power supply wire meets the wire coming to the gadget you’re testing. Just remove the lid and unwind the cables from around each other.  

#3. If needed, strip the wire ends.

Wrap a tiny amount of wire all around the multimeter prongs, or leave enough wire exposed so the alligator prongs can firmly clamp on. If the wire is completely insulated, grip your wire clippers approximately 1 inch (2.5 cm) from the end. Squeeze just enough to cut through the rubber insulation. Then, quickly pull the clippers away to you to extract the insulation.

#4. Wrap the multimeter’s positive probe with the positive wire.

Wrap the exposed end of the red wire away from the power source with electrical tape. Attach the alligator clips to the wire or wrap the multimeter probe’s tip around it. In any event, to obtain an accurate result, ensure that the wire is tightly secured.

#5. Power the circuit by connecting the black multimeter probe to the last wire.

yellow color multimeter

Locate the positive wire leading from the electrical device you’re testing and connect it to the black multimeter tip. If you disconnect the cables on a battery-powered circuit, it will restore its power. Turn on the electricity if you shut it off with a fuse or a switch.

#6. While reading the meter, leave the devices in place for roughly a minute.

Once the meter is in position, you should instantly see a value on the display unit. It is the amperage or current measurement for your circuit. For the best accurate measurement, keep the devices in rotation for at least 1 min to verify the current is stable.

Note: If the result is less than the cautious level (for example, 0.3 A when the sensitive level measures up to 300 mA). Unplug the meter, change the red probe to mA, and rerun the test.

You may want to check other multimeter tests we’ve written below;






References
(1) safety measures – https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/prevention.html
(2) power source – https://www.sciencedirect.com/topics/engineering/power-source

About Sam Orlovsky

b1d87d2ee85af3e51479df87928bdc88?s=90&d=mm&r=gI realized early on carpentry was a huge passion for me and I’ve stayed in the industry for over 20 years now. This gives me a unique ability to really be able to tell you what the best tools and recommendations are. I’m not only a carpenter but I also like machinery and anything to do with electrics. One of my career paths starting off was as an apprentice electrician so I also have a lot of experience with electrical products and anything related.