10/2 or 10/3 For Mini Split: Which Wire Should you Use?

Heating, ventilation, and air conditioning units (HVAC) are great ways to maintain an ideal atmosphere in your living area in winter or summer.

When setting up an HVAC unit, it is paramount to request the services of a licensed electrician who will set it up for you quickly and safely.

However, you can decide to set it up yourself if you are a DIY person. You will need to learn about Mini-splits, especially which wires are best to use for your specific unit.

This article will discuss which wire size is mainly used for Mini-split HVAC units.

What Do 10/2 and 10/3 Wire Numbers Mean?

You might be wondering what the numbers 10/2 and 10/3 mean? The US has a system for naming the wire size and connectors for the air conditioner.

The first number is known as the American wire gauge. It is a standardized wire naming system in the USA that has been in use since 1857.

In the American wire gauge, the large numbers mean smaller wire size diameter and thickness. In this case, the 10 gauge is the ideal and commonly used wire size thickness for air conditioners. The wire supports both the cooling and heating element of the Air conditioner.

The second number refers to the connectors that the wire has. For example, the 10/2 wire has two connectors (a hot and neutral wire). The 10/3 wire has three connectors. (two hots and one neutral wire)

10/2 or 10/3 Wire: Which is Best for your Mini-Split Air Conditioner?

A vast majority of Mini-splits in the US use a dedicated circuit. They are also single circuits so the best wire gauge option would be the 10/2 wire. A 10/2 wire configuration is sufficient for the power needs of a 220v air conditioner.

The 10/2 size wire works best for an air conditioner as it can accommodate both functions of an HVAC system, whether it is heating or cooling.

The 10/3 wire size is best for an appliance that can provide both negative and positive voltage. However, this kind of setup is hard to come by for most air conditioners in the market. So the 10/3 size wire becomes obsolete in this case.

Another reason why the 10/3 wire is pointless for most air conditioners is because the extra wire (neutral wire) is unnecessary for an air conditioning unit.

Safety Tip for 10/2 and 10/3 for Mini-Splits

One concern here is using a smaller gauge wire than what is required. The air conditioner would not be able to handle the electrical power voltage passing through the wiring.

When you use a small gauge wire than is required, the electrical current faces a lot of resistance as it flows. The result of this is that the wire becomes very hot.

The danger is that the wire could melt, resulting in a fire. You could also potentially spoil the appliance and incur hefty repair costs. Worse still, you could cause a fire, leading to loss of life and property.

However, using a larger gauge wire than is needed does not warrant much concern. Usually, the current that passes through here is not as much. It will only inconvenience you since it is stiffer.

Another safety concern is that the person installing the disconnect box should place it next to the outdoor unit of the AC. It allows for safely turning off power when routine maintenance or repairs are done.

Another concern is that when setting up your air conditioner, make sure you correctly set up the ground wire. The ground wire can protect your air conditioning unit from power surges.

Importance of Using the Right Wire for your Mini-Split AC Unit

It is paramount that you use a suitable wire for installation. Correct wiring will ensure that you get the most performance from your air conditioning unit.

Wrong wiring might bring about safety issues making your Mini-split unit potentially dangerous. The recommended wire size for air conditioners is 10/2 or 10/3. They are compatible with most Mini-split units on the market.

Another reason why you will want to use the correct wire gauge is to ensure wire flexibility, especially when making the actual connection.

For example, you might use a stiff 14 gauge wire that cannot fit into the connector ports. Or you could use a wire smaller than a 10 gauge and end up with a bunch of mixed-up, looking very messy and bundled up. They may even hamper maintenance or repairs needed in the future.

When Do I Use 10/2 and 10/3 for Mini-Split AC?

The 10/2 wire is for single circuit appliances, and the 10/3 wire is for dual voltage appliances.

If your Mini-split has a single circuit setup, the 10/2 wire size would be ideal. These units are configured because each of the two units only requires 110 volts.

And if your air conditioner has a dual voltage setup, the 10/3 wire size would be perfect.

What is the Difference Between 10/2 and 10/3 Wire?

Both the 10/2 and 10/3 are the same gauge of wires. So what is their difference?

The first difference in these wires is the number of current-carrying cables. The 10/2 has two wires, A hot and a neutral. The 10/3 wire has three wires. It has two hot wires and one neutral wire.

Apart from the current-carrying wires, both wires have a ground wire.

For easier identification, the hot wire has black insulation, neutral cables have white insulation, and ground wires have green insulation.

The 10/2 and 10/3 wires can accommodate 30 amps in terms of voltage.

Choosing the Right Gauge; What Gauge Wire Do I Need for a Mini-Split?

When choosing the right gauge for your Mini-split, you will have to consider the voltage of your air conditioner.

Different wire gauges have different voltage capabilities. There are various sizes of wires. They include;

  • 16 gauge that can accommodate 13 amps
  • 14gauge that can accommodate 15 amps
  • 12 gauge that can accommodate 20 amps
  • 10 gauge that can accommodate 30 amps
  • 8gauge that can accommodate 40 amp
  • 6 gauge that can accommodate 55 amps
  • 2 gauge that can accommodate 115 amps.

Generally, when an appliance has a higher amp rating, the larger the electrical wires.

The 10 gauge wire will work well since ACs generally require 30 amps for the Mini-split air conditioner.

The 10/2 wire size will serve your air conditioning needs well enough, so ultimately, it is the best wire for your Mini-split AC. You will also find this wire size as the recommended wire size for dryers, washing machines, and refrigerators.

How to Wire a Mini-Split

Electricians and technicians follow a standardized handbook, the National Electrical Code (NEC). They also use codes defined by local areas or buildings concerning electrical wiring.

You should also follow the same regulations if you intend to DIY when installing wiring for an air conditioner.

Things You Will Need;

You will need to keep referring to your owner’s manual of the unit because the installation techniques and requirements might vary slightly with every model.

You will also need to know the AC electrical voltage, which is usually around 220 volts, with some units being as low as 110 volts. This information will be crucial in determining the breaker setup with the correct amps.

Another thing that you will want to consider is where to put the external unit. It needs to be close to the disconnect box and raised from the ground. You might want to consider installing a solid base for this unit.

With this information, you can begin the technical work of wiring your Mini-split system.

Step 1;

Start this process by switching off the power at the mains. Eliminate the possibility of electrical shock.

Step 2;

Install the disconnect box that can easily cut off power.

Remember the disconnect box should be mounted next to the external unit of the AC. It is important to help a technician easily switch power off when maintenance and repairs. In addition to this, it is required by code to install it next to the external unit.

Step 3;

Connect the disconnect box to the installed external AC unit. For this, you will need an Electrical whip. It is a prepackaged wire and can carry high voltages, so it is ideal as it can hold 220 volts for most ACs.

Step 4;

Set up the circuit breaker. You can use a double pole breaker since it can handle a 240-volt circuit for most Mini-splits. It can also handle two 120 volt circuits if your ACs voltage is within that range.

Step 5;

Wire the breaker box to the disconnect box using a dedicated power line. You will need the right wire size, the 10/2 for an air conditioner, and the correct wire length.

Since the location of the breaker box and the external Mini-split is always different, you will need to find a way to guide the wires safely, preferably using a conduit to house these wires. It will help with protecting against the elements.

If your house has double walls, you can run the conduit through the walls of your home.

Step 6;

Connect the wires that join the indoor and the outdoor unit. These connections depend on the Mini-split system’s setup, whether it is for one room or several rooms.

For multiple indoor units, you can number them for easier referencing when connecting the right color wires. You must get this step right because the proper functioning of your Mini-Split will depend on it.

It also helps if you use a ground wire from the main breaker box to the metal plate located below the connections. If a wire hangs or becomes loose such that it is exposed to the elements, grounding is a sure way to protect against electric shock.

Final Takeaway

It is also paramount that you use the services of a qualified technician while installing an air conditioner unit. And if you are a DIY person, consider doing due diligence in researching an article like this one to get helpful information on Mini-splits.

It can have long-term benefits since your unit will be configured appropriately with the suitable wire to improve its functionality and make it last for long.