Understanding Mini Split Wire Sizes

 July 11, 2023      Jeff Rosenblum

We prioritize providing you with the best support for your HVAC needs. Lately, we have received numerous inquiries regarding wire sizes for connecting indoor units and line sets in Mitsubishi Electric and Breeze33 Mini Split equipment. We want to ensure that you understand these specifications clearly for optimal performance and reliability.

Adhering to the recommended wire sizing is crucial for proper operation. The wire not only carries voltage for the indoor unit but is also used for communication. Oversized wires can negatively impact communication, leading to errors and inefficiencies.

Another essential aspect to consider is line set sizing. It is imperative to match the line set size with the requirements of the indoor unit, regardless of the port of the outdoor unit or branch box. For example, if the indoor unit specifies 1/4" - 3/8", the line set must be 1/4" - 3/8". In cases where a change in size is necessary to connect to the outdoor unit or branch box, we offer adapters that can be used at those connection points.

Here is a reference guide for selecting the appropriate wire sizes:

Mitsubishi Electric Mini Split Equipment Wire Size Additional Notes
M Series 1-to-1 System (1 indoor, 1 outdoor) 14ga -
P Series 1-to-1 System, 6 Series or lower 16ga -
P Series 1-to-1 System, 7 Series or higher 14ga -
M Series Multi-Zone System WITHOUT a branch box 14ga -
M Series Multi-Zone System WITH a branch box

16ga wire from the indoor head

to the branch box.

A 16/2 stranded shielded wire is required to run from the branch box to the outdoor unit for communication. It will also need 14/2 wire to be run from the branch box to the outdoor unit (this powers the box).

Breeze33 Mini Split Equipment Wire Size
Generation 1 Units 16ga
Generation 2 Units 14ga

Our HVAC Customer Support team is here to assist you. If you have any questions or require further clarification, please don't hesitate to contact our knowledgeable team at 330.475.8230.