What size wire for 220v AC unit?

The key to powering up a 220v AC is knowing which size wire the unit needs to ensure the wire can handle the electrical load.

Air conditioners are electrical household appliances that need to be powered, since they depend on electricity to function. If an air conditioner is not connected to a power outlet, it will not start or work, and no cooling will take place. Air conditioners need to be powered up correctly.

An air conditioning unit can be a huge energy consumer. In some instances, they cannot be connected to a regular electrical outlet because the point would simply be too small to handle the unit’s electrical load.

Wiring is also a big factor when it comes to air conditioners, and the volts they produce as well as the wires they use need to be sized correctly to handle the voltage of the unit.

Wire sizes and volts

Wires come in different sizes. The size of the wire is determined by its gauge number. Typical wire sizes range from 10-gauge to 14-gauge. One might assume that the higher the gauge number is, the bigger or thicker the wire is, but this is not the case.

The smaller the gauge number, the bigger or thicker the wire and the more capable it is of handling powering appliances as large as air conditioners.

An air conditioner needs to be powered by a circuit that has a certain amount of volts, and if you have a much larger AC unit of 1 ton (12 000 BTU) or more, it will need a dedicated 220v circuit.

What size wire for 220v AC unit?

Some people wrongly believe that the size of wire they need for their air conditioner is determined by its voltage, but this is not true.

The size of wire required to power up an air conditioner is determined by the unit’s cooling capacity in British Thermal Units (BTU). The BTUs are the unit’s cooling capacity, in other words, it is the amount of power the AC has to cool.

A wire powering up any unit needs to be able to withstand the BTU power and supply the air conditioner with enough power to operate at its optimal capacity with ease.

The bigger the air conditioner’s BTU is, the bigger the wire it will need to power it with electricity. Generally, much larger air conditioning systems use 220-volt circuits to run.

If you have a unit that requires 220v, it is crucial that you get the right wire size for it. That will also be partially dependent on the unit’s cooling capacity.

For 220v air conditioning units starting from 12 000 BTUs and up, the correct wire size for the circuit breaker is a 10-gauge, or even a 12-gauge wire.

This is because you will need a much thicker wire to handle air conditioners as big as and bigger than 1 ton, due to their high cooling capacities.

Why do 220v air conditioners need thicker wires?

The reason your 220v air conditioner needs a wire that is quite thick is because of the electrical current it carries. A wire needs to be able to handle the high electrical current that a larger 220v air conditioner sends through wires when it powers up and while it is running.

If the wire is too small for the high demand current of the AC, this could cause a fire by frying the circuit, and this will damage the air conditioner itself in the process.

Are 220v and 240v the same?

220v and 240v are the same in that they have the same voltage level and the same electrical outlet. You can also use the same size wire for both voltages because they have the same voltage level. Moreover, the 240v plug also has the same counterparts as the 220v plug.

How to calculate the size of wire needed

If you are not sure of which size wire you need for your 220v air conditioner, you can calculate the size you need according to the ampacity of a wire.

To do this, you first need to calculate the max wattage of the 220v unit, and then calculate its amps using the 220 volts.

Account for the 80 percent National Electric Code rule that states that the amps should be multiplied by a 1.25 factor, and once you have the minimum required amps, you can check for wires with enough ampacity.

Calculations for wire size:

  • Max wattage = BTU of AC ÷ EER rating
  • Amps = max wattage ÷ 220v
  • 80 percent NEC rule = amps x 1.25
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