Mini-Split Ductless AC Unit: Electrical Wiring Codes Explained

Introduction to Mini Split Ductless Air Conditioners

Hey guys, Joshua Peterson here with Peterson Electric. In this article, I want to talk about mini split ductless air conditioner systems. This video is from March of 2018. We will discuss the wiring for these systems, as well as some code requirements and considerations for installation. Please note that while we do not install these systems, we do wire for them.

A mini split is a type of air conditioner that does not require ductwork. These units can sometimes also function as heaters. In this particular case, there will be two condenser fans, one in the kitchen and one in the hallway, off of one 30,000 BTU unit.

Understanding the Specifications

It’s important to understand the specifications of the mini split system being installed. In this case, the unit is rated at 22 amps, with a maximum overcurrent protection device rating of 25 amps. This information can help to determine the minimum wire size required for installation.

Additionally, be sure to check the panel for the enclosure’s amperage rating. In this case, the panel has a 10,000 ampere current rating. This means you need to refer to the breaker for further information.

Finding the Breaker Information

In this installation, the breaker being used is a Cutler Hammer CH version. It has a torque specification and temperature rating of 60°C-75°C. However, you will need to use the lowest temperature setting, which is 60°C. The breaker itself is a 25 amp, two-pole stab-type breaker.

To accommodate this breaker, a twin was run in to provide power for the dedicated circuit required for the air conditioner. This is in accordance with Article 210.63 of the National Electrical Code, which requires an accessible 110-volt plug be provided within 25 feet of the outdoor unit. In addition, this plug must be GFCI-protected, as specified in Article 210.8.

Wiring the Mini Split System

For this installation, a 3/4″ EMT conduit was used to house the 10-gauge and 14-gauge wire. The 14-gauge wire is for an additional 110-volt plug requested by the client. The mini split unit will be wired up with a 25-amp FLNR fuse rated for use with LittleFuse products.

The wiring will need to be separated into line and load sections, with the line section connecting to the breaker and the load section connecting to the mini split system. An outdoor-rated GFCI receptacle with a weather-resistant cover was also installed nearby to provide a dedicated, code-compliant power source for the air conditioner.

Selecting the Appropriate Wire Size

It’s important to choose the correct wire size for your mini split installation. In this case, a 10/3 wire was selected based on the 22-amp rating of the system and the 25-amp maximum overcurrent protection device limit. To determine the appropriate wire size for your project, consult the National Electrical Code and the specifications for your particular mini split system.

Final Thoughts

Properly wiring and installing a mini split ductless air conditioner system can be a complex process that requires careful attention to code requirements and system specifications. By understanding these elements and following the appropriate steps, you can help ensure a safe and efficient installation for your mini split system.

Remember, while we do not install these systems, we do wire for them. If you have any questions about your specific installation or need assistance with the electrical process, don’t hesitate to reach out for assistance. We’re always here to help.

You May Also Like