How to Choose a Wire Size for an Air Conditioner?

Wiring is the most important part one needs to look into when attaching a new appliance. Poor wiring can be hazardous, and thus one needs to be very well versed with the proceedings. This is the case, especially with air conditioners. In addition, depending upon the number of machines you have in your house, the voltage may vary. That is why you need to choose the correct wire to hold the load. 

Before we get into choosing a wire, we need to understand resistance. According to the law, resistance is directly proportional to the length of the wire. Therefore, if the length increases, so will the resistance. Now that we have gotten that cleared up, we need to focus on the thickness of the wire, which leads us to the following read. 

Importance of good wiring 

Air conditioners are huge investments that have been spread over the years. However, just buying an AC is not the end of the story; you will need to attach it, wire it and maintain it in the long run. Whenever an air conditioner is put up, the wiring of the machine is paid close attention to. This is because it is the most important part of putting up an air conditioner. 

While the machine may malfunction due to its own expense, problems in wiring may become a rather larger expense to produce. Irresponsible wiring can destroy the machine and take lives in extremities. Thus, it would help if you were very careful when attaching the wires in your place. If you are one doing it, get protective gear like rubber gloves and footwear. 

How to choose the right wire for your AC? 

Understanding the tonnage and the capacity of an air conditioner is rather difficult if you are new to it. Therefore the wiring of the machine and its power supply is a more difficult task. Professionals can explain the procedure, but you’ll forget all about it by the time you get your next AC. Hence, here are some pointers that will help you choose the right wire for your air conditioner: 

1. Find out the power supply required. 

The right wire should come to the house depending on the power supply. You can easily find the power supply amount written on the casings or specifications of the machine. For example, the power supply of an air conditioner depends on the weight of the machine and the brand it belongs to. 

2. The running current of the air conditioner 

Estimating the running current of the air conditioner is an essential part of appropriate wiring. However, wrong calculations can lead to mishaps that may turn the machine’s fatal. Hence here is an easy way to calculate the running current.

Let’s say that the highest power input of an air conditioner is 2500. The standard voltage of an air conditioner is 220V. If you want to calculate the running current, the equation stands down to I=P/Vcosθ, where cosθ is valued at 0.9. Therefore the running current would amount to 2500/220*0.9, around 12 Amp. 

3. Find out the starting current 

Running current is essential and takes a chunk of current when the air conditioner is active. A lesser-known fact is that the machine takes more current when the air conditioner is just starting. That means when the AC is switched on, and it absorbs relatively more current than when it is running. According to the rule, when ac is starting, it takes 1-1.5 amp more current from the circuit breaker. Talking to a professional about the right wire considering the starting current, is wiser. 

4. Finally, understanding the wire size and choosing 

When selecting a wire for your AC, you need to pay more attention to the starting current. For example, in the earlier instance, the starting current for 12amp would be I=12*2.5. Whatever is the result will produce a relative thickness of the wire. Hence the best way to go about this is by talking to a professional who can suggest the perfect wire depending upon the amount of load that needs to be carried.  

If you have more than one air conditioner in the house, ensure that the resistance is enough to keep the power below the standard level. If the load happens to go over what it can carry, then the circuit switch will trip. 


Finding the right wire can be a pickle if you are unsure of going about the proceedings. Therefore, you must talk to professionals regarding the same. Teasing electricity and attaching the wrong wires with the wrong voltage is scary. It can damage the machine and cause problems in the house. Thus, it is best to call for professionals with better knowledge and experience to make the right choice and keep you and your family safe. 

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