How to Measure AC Voltage with a Multimeter in 8 Simple Steps

Do you know how to measure AC voltage with a multimeter? But, before getting that, you should know what it is and its parts. A multimeter is a device that electrical device maintenance professionals use to measure voltage current and resistance.

Voltage is different in AC for the reason that usually, you find them offered in two categories. For example, a whole home air conditioning unit has a central heating system while a window air conditioner cools individual rooms, all of which matter with voltage.

For an AC to work correctly, it requires a particular voltage supply. An expert measures the voltage in AC to ensure it’s not putting a strain on the home electrical system. Also, a voltage difference between an AC unit and the power source could cause damage.

It’s easy to use a multimeter to measure AC voltage, especially if you are an expert, since there are interpretations to make. Before getting to learn how to measure AC voltage using a multimeter, it’s essential to the amount of voltage the two categories of air conditioners need to function.

Voltage Required For an Air Conditioner to Operate 

A central air conditioner operates on 220 or 240 volts on a dedicated circuit. Your central air conditioner consumes 5000 watts of electricity the first time you switch it on. Expect to start paying more for utility when you have it.

Your monthly utility bill gets interesting if you get a larger central air conditioning unit since it consumes more energy. The cooling power of an AC unit gets measured in British Thermal Units (BTU). A unit with high BTUs has high cooling power.

On the other hand, a window air conditioner requires 110/120 volts or 220/240 volts to function as intended. The voltage you get depends on its cooling capacity. You can use a standard 110/120-volt power source to run an air conditioner with 15000 BTUs designed to cool a small room.

Consider getting a large window conditioner, although it also consumes plenty of power. Connecting it to the power source and other appliances could overload.

Understanding the Parts and Functionality of a Multimeter

Before getting into the nitty-gritty of how to measure AC voltage with a multimeter, it’s vital to know what it is and its parts. Firstly, the multimeters currently used are digital and helpful in checking current, voltage, and resistance.

A multimeter comes with an LCD to show you the results after measuring. Some have LCDs that you can read even in darkness. Another essential part is the rotary range sector dial for selecting a function on the meter. A non-auto-ranging multimeter allows you to select range well.

The other parts you’ll work with are the connection ports (female sockets) where you insert 4mm probes. Probes are components with pointed ends that touch the point of measurement. They also have a plug to connect to a socket.

How to Measure AC Voltage with A Multimeter

Now that you know how a multimeter works, you can proceed to measure the voltage of an AC. Before proceeding, ensure you understand all the figures and symbols on the multimeter. Look at this step-by-step set of instructions on how to measure AC voltage.

Step 1: Switch off the air conditioner’s circuitry. The first thing you must do is cut off the power supply to the unit. Skipping this step risks shorting adjacent wires and terminals.

Step 2: Insert the black ground probe into the COM socket. It’s indicated on the multimeter.

Step 3: Insert the other probe next into the socket that has a V label. If you don’t see that label, look for the Greek letter ‘Ω,’ which is an omega with a diode symbol possibly accompanying it.

Step 4: Your meter might have a manual range selection. If that’s the case, turn it so that you can select AC or DC voltage. You have to pick a range to achieve accuracy. The dial should be at the ‘V’ setting for an automatic one. It has a symbol for AC or DC.

Step 5: Connect the multimeter to a parallel circuit. It is the way to measure voltage. Connect the two test probes parallel to the air conditioner.

Step 6: Locate the wiring’s first point, connect it to the black probe, and then turn the power to the air conditioner back on.

Step 7: In this step, you can finally connect the red probe to the second point of the probe. Don’t allow your fingers or the tips of the probes to touch.

Step 8: The reading should be on the LCD on the multimeter.

Benefits of Enlisting a Professional to Measure AC Voltage on a Multimeter

  • Interpretation of results. The most apparent reason you should let a qualified professional measure the voltage in your AC is interpretation. The symbols on a Multimeter have meanings that are hard to understand if you are without training.
  • Safety. When operating electrical appliances, it’s better to be on the safe side and leave it to an expert. Some steps are necessary to protect from electrocution or short the device. Also, an expert knows which parts are the most delicate.
  • Accuracy. You may not know the proper level of voltage that your unit should be running on. An experienced professional will know what recommendations to give based on the voltage reading.
  • Speed. You can’t rush the process of measuring the voltage of an AC with a multimeter. Still, allowing an expert to do it ensures your unit is up and running fast. You would take more time if you DIY.

Final Words

As you figure out how to measure ac voltage with a multimeter, you should have answers as to why it’s essential in the first place. Additionally, interpretation of the reading on the multimeter requires some training. That should be why you must consider leaving that work to an expert.

Again, in learning to measure ac voltage, you can rely on the ac unit manufacturer to tell you first. Usually, there is a sticker or a manual on the unit. If the voltage is already indicated, you may proceed to measure the voltage with a multimeter for confirmation.

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