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I know how creepy household wiring can be if you’ve never done it before. However, learning how to test electrical wires with multimeter is super easy and safe if you know what you’re doing.
So, let me guide you through all these seemingly complex steps so that you can test your electrical wires without calling the local electrician. Got your multimeter on hand? Then follow all these simple steps..
Direct Current & Alternating Current
Any information about how to test electrical wires with multimeter shows up the term alternating current and direct current. Although both words include current, they don’t mean the same thing.
For instance, direct current or DC, for short, refers to electrons that flow in one direction, meaning they do not change during this process.
On the other hand, alternating current or AC can change over time, meaning the flow of electrons changes.
This might seem confusing, but just keep in mind that your house runs off of AC, and your car’s battery uses DC.
Types of Multimeters
Figuring out how to test wires for power with multimeter can be challenging—especially when multimeters come in all shapes and sizes. For instance, high-end models can cost hundreds of dollars. Thankfully, a cheap multimeter is good enough to get by.
In your search, you might notice that there’s a dialog and analog multimeter. A digital one will display the voltage on the screen, whereas an analog one will use a needle to indicate the voltage.
Testing Electrical Wires Using a Multimeter
Now that we’re on the same page, here’s how to test power cable with multimeter:
1. Getting Started
To set up your multimeter, gently plug the meter leads into the terminals. Notice that your multimeter includes a set of wires or leads. The black wire goes into the negative side of the terminal, and the red one goes into the positive side.
2. Identify the Symbols on the Multimeter
Understanding what the symbols on the multimeter mean is crucial before testing your wires. You do not want to misunderstand these symbols when troubleshooting. That said, here’s a shortlist for these terms:
- The capital V with a curvy line on top refers to AC voltage.
- The capital V with a straight line on top refers to DC voltage.
- The letter m with the capital V refers to AC millivolts.
- The current symbol going to the right refers to OHMs or continuity.
The only thing we care about is the OHM symbol. So, go ahead and set the unit to the continuity setting.
3. Grab the Leads
Here’s how to test wires for power with multimeter: after setting up the multimeter, grab both the negative and positive leads, and put them on both ends of the extension cord. If you’re not getting any numbers on the multimeter, that means somewhere along the path, the wires have shorted out. Thus, you’ll have to fix or replace the extension cord.
4. Test the Outlet
Using the same concept I covered above, you can test several things at home. However, some might require different settings. For example, to test a circuit, you must set the multimeter to AC volts to see if the circuit has power.
Before testing the circuit, please keep the following information in mind:
- The small plug on the outlet is the hot wire.
- The larger plug on the outlet is the neutral wire.
- The rounded plug, which looks like a mouth, is the ground wire.
When testing the outlet, please start with the neutral wire. If you connect the hot side first, the other terminal lead will become energized, making this simple job incredibly dangerous.
After hooking up both leads to the outlet, the multimeter will show up the voltage on the screen. If the multimeter shows the proper voltage, then your outlet is in great shape.
Frequently Asked Questions
Got any questions about electrical wires and multimeters? Here is some helpful information on how to test home electrical wires with multimeter:
How do I test a 12-volt wire with a multimeter?
- To test a 12-volt battery, set the multimeter to 20 volts on the DCV section. Next up, hook up the positive lead to the positive side and the negative lead to the negative side. The multimeter should now display the voltage.
How do you check 240 volts with a multimeter?
- Before testing the outlet, please wear safety gloves and glasses. Once that’s done, set the multimeter to volts AC. Next up, grab two leads and plug them into the outlet. Your multimeter should now pick up the electricity and display the corresponding voltage.
How do I know if my house has electrical problems?
- If the outlets feel abnormally hot, you probably have an electrical problem at home. Moreover, if the lights keep flickering, you might want to check your electrical system.
How many Ohms are considered an open circuit?
- The electrons that travel through the wires need a continuous path to return to the source. However, if they can’t flow through, you got an open circuit somewhere in the wire. If that’s the case, you shouldn’t get any power on the multimeter.
You should never mess around with electrical wires. But as long as you know what you’re doing, there shouldn’t be much of a problem.
Learning how to test electrical wires with multimeter is super easy, and with all my tips, you should be able to test your electrical cables at home.
The multimeter looks pretty intimidating with all the symbols it has. But you only care about the AC and DC section. Remember, North America uses 110 to 120V AC, while European countries use 220V to 240V AC.