How Much Voltage Does a Refrigerator Need?

Any refrigerator that plugs into a standard wall outlet runs at a voltage of 120 volts, which is basically the same as 125 volts or even, as you might find listed on some appliances, 115 or 110 volts. In other words, the refrigerator voltage is the same as the voltage of an LED TV or that of any other appliance that plugs into a wall outlet.

We're not counting super high-capacity refrigerators that you might find in commercial kitchens. These usually run on 240-volt (equivalently 220-, 250- or 220-volt) power and have large plugs shaped to fit only into 240-volt sockets.

While household refrigerators all run on the same voltage, they draw different amounts of current depending on the model, and that translates into different power consumptions. Moreover, any given refrigerator draws more current and more power when it cycles on than when it runs. The extra current draw at startup can make the lights in the house go dim and is a common cause of blown breakers.

Time for a quick review of basic electrical terms. In high school, you may have learned that scientists visualize electricity as the flow of negatively charged particles called electrons. When these travel through a conducting wire, you can define three quantities:

• Voltage (V), measured in volts, is the strength of the force or pressure propelling the electrons through the conductor. Electrons have a fixed charge and are attracted to a positive pole and repelled from a negative one. Increase the charge between the attractive and repulsive poles and the electrons are more motivated to move.

• Current (I), measured in amperes (amps), is the number of electrons that pass a given point per unit time. To use the analogy of water flowing through a pipe, current is the volume of water flowing at any given time. By the same token, voltage is analogous to the pressure pushing the water through the pipe.

• Power (P), measured in watts, is the amount of energy possessed by the electrons as they flow. You calculate power by multiplying the voltage by the current (P = VI).

The power grid throughout North America must conform to a single voltage or it would be impossible to standardize lights, electrical appliances and consumer electronics. Generating plants produce high-voltage electricity, but through the use of transformers, the voltage is stepped down at the point of use to 240 volts. A pair of hot wires carries this 240-volt electricity into each residential panel where it's further split into two legs, each at a voltage of 120 volts relative to ground.

All the standard outlets in a house draw power from one or the other of these two legs. Certain appliances, such as water heaters and stoves, function more efficiently at a higher voltage, so they use both legs from the panel to draw 240-volt electricity. These appliances have special plugs, and the refrigerator usually isn't one of them.

Most refrigerators plug into a standard wall outlet, just like lamps, kitchen appliances and TVs, and just as a TV voltage consumption is 120 volts, so is the voltage consumption of a refrigerator. This doesn't mean, however, that the refrigerator and TV consume the same amount of current or power.

Generally, a refrigerator draws more current than a TV because it needs more power to do the work of circulating refrigerant through the coils. Whereas the TV amps draw is usually less than 0.5 amps, a refrigerator draws anywhere from 7 to 10 amps. However, that's just when the refrigerator compressor has started and the refrigerator is running.

When the refrigerator compressor starts up, it can draw up to three times the current it draws when it's running. This is because it takes that much more power to get the compressor moving from a standstill. This extra current draw is what dims the lights and causes breakers to trip.

You can determine the current draw of your refrigerator by checking the label, which is usually affixed to the back near the compressor or to the compressor itself. The label lists the model and serial numbers, as well as the voltage and current draw, and sometimes the power draw as well. Don't worry if the label specifies the voltage as 115 or 125 volts rather than 120 volts because they all mean basically the same thing.

If you're concerned about how your refrigerator impacts your overall energy consumption and energy bill, you want to know how much power the appliance draws. You might find this listed on the label, but if not, it's easy to calculate.

Remember that power is the product of voltage and current. You can find the current on the label, and even though voltage may vary from 115 to 125 volts, you're always safe using a nominal value of 120 volts. Multiply these together to get the power consumption of the refrigerator in watts.

For example, if the label tells you that the current draw is 7 amps, the power consumption is 120V× 7A = 840 watts, which is about the same as an electric heater at its lowest setting. If the current draw is 10 amps, the power consumption is 1,200 watts, which would be roughly equivalent to the same heater set at medium heat. Don't forget that the refrigerator will draw up to three times that power momentarily each time it starts up.

A refrigerator should be on a dedicated circuit, which means that it doesn't share the circuit with any other appliances. The reason for this is to prevent overloading the circuit and tripping the breaker when the compressor starts up. Consequently, you only need to take into account the refrigerator's current draw when choosing a breaker for the circuit.

Generally, a 20-amp breaker will work for most refrigerator circuits. The starting current seldom approaches a full three times the running current and can be significantly less if the refrigerator is a newer, energy-efficient model. Some models may only require a 15-amp breaker, but if you install one of these and find that it keeps tripping, you'll need to replace it with a 20-amp one.