Extension cords are one of the most resilient electrical components. These power equipments can last for years, provided that you buy premium quality and observe the basic dos and don'ts while using them.
However, even heavy-duty extension cords will develop malfunctions sooner or later. The faults may be due to normal wear, physical stress, or wiring problems.
Before repairing a malfunctioning extension cord, it’s best to check if its conductors are still transmitting electrical current normally. The simplest and safest way to do that is by using a multimeter.
Here’s a beginner’s guide to a multimeter and how you can use the device to test your extension cord’s functionality.
What Is A Multimeter?
A multimeter is an instrument designed to measure multiple electrical variables. Most of these gadgets can measure electrical current, resistance, and voltage.
Buying a multimeter saves you the cost of investing in a separate ammeter, ohmmeter, and voltmeter. Depending on the instrument, you may be able to measure additional variables like temperature and capacitance.
More About Current, Resistance, and Voltage
In electrical parlance, current refers to the amount of charge that flows through an electrical circuit in unit time. It’s typically measured in amperes.
Heavy-duty extension cords handle electric current better than their lighter-duty counterparts. Most heavy-duty cables have a gauge rating of less than 12, while the converse is true for lighter-duty wires.
An extension cord’s gauge denotes the thickness of its conductors, with thicker wires represented by smaller gauge ratings. The larger the conductor diameter, the more efficient it is at transmitting electric current.
A 16 gauge extension cord is an excellent example of a lighter-duty extension cord. Due to the thinner diameter of its conductors, this cable can only handle less power-hungry appliances like lighting fixtures. That’s in contrast to 12-gauge extension cords, which have thicker diameters and can power heavy-duty equipment like refrigerators.
You may want to study extension cord gauge charts thoroughly to understand the interplay between conductor thickness and current transmission.
Voltage measures the pressure that pushes charged electrons as they flow through an electrical circuit. It’s also known as potential difference or electric tension.
Just like current, an extension cord’s voltage rating depends on its gauge. A lower extension cord gauge (thicker conductors) translates to higher voltage stability.
Other factors like cable length also impact voltage.
Note that an extension cord’s voltage drops with every square foot. Therefore, a 50 foot extension cord would be more reliable for connecting high-voltage equipment than a 100- or 150-foot wire.
Lastly, resistance measures the opposition to current flow in a circuit. It’s also known as impedance, and the opposite is conductance.
How to Use a Multimeter to Test an Extension Cord’s Functionality
1. Take the necessary precautions
Like any electrical troubleshooting process, certain precautions are necessary while using a multimeter.
First, ensure the multimeter isn’t damaged in any way. If the surface is broken and you must use it, don’t touch any exposed wires.
It’s also important to wear rubber shoes and insulated gloves before using a multimeter. This prevents your body from becoming a conduit to the current and potentially suffering shocks or electrocution.
Regardless of if you’re wearing safety gloves, keep your hands off a multimeter’s metal probe tips. Don’t switch the settings while still connected to the circuit either.
2. Unplug your extension cord
Most extension cords draw power from the wall socket, although some may be connected to other power strips in a daisy chain.
In any case, unplugging the extension cord is important to avoid electrical shocks.
Even if you use the best extension cord with proper insulation, the risks of touching exposed conductors are real. So, it’s best to completely unplug the cable from its socket.
3. Adjust the multimeter settings
If you’re using a digital multimeter, you’ll need to turn the dial to resistance or ohms.
Ohm is represented by the symbol Ω. On a multimeter, the symbol may appear on the dial alone or share a position with several other test modes.
The maximum resistance setting can range from as low as 20MΩ all the way to 20MΩ, depending on your multimeter's quality.
4. Complete the test
Locate the red and black probes in your multimeter. The red probe goes into the hole in the extension cord’s socket end, whereas the black one goes into the round prong on the cable’s plug end.
Now, listen out for any beeping sound, which indicates the circuit is complete. The sound is around the same decibels for different extension cord sizes. Therefore, don’t focus much on the volume.
Repeat the steps with the remaining sockets and plugs, keeping your ears out for a beeping sound in each case. If you can’t hear the sound, it’s time to replace your extension cord.
Multimeter FAQ
Is a multimeter’s efficacy dependent on extension cord size?
The different extension cord lengths do not affect a multimeter’s performance.
Why isn’t my multimeter working?
Your multimeter doesn’t work commonly because you’re mismatching the probes. Another reason is that you’re using the wrong settings.
What’s the best way to store a multimeter?
To prolong your multimeter’s durability, store it in a clean, cool, and dry place.
Wrap Up
A multimeter is a handy device that should never be missed in a homeowner’s toolkit. The instrument is designed to measure various electrical metrics, including current, voltage, and resistance.
However, a multimeter’s significance doesn’t stretch beyond troubleshooting extension cord problems. As for major repairs, it would be prudent to engage a licensed electrician.