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How Do I Determine the Breaker Size and Wire Needed for a Pioneer HVAC System?Updated a year ago

Determining Breaker and Wire Size for Pioneer Split Systems

Breaker Size

There are 3 ways to determine the breaker size and wire type needed for a Pioneer HVAC System.

1. Checking the product page

Go to the product page you are interested in and scroll down to the Outdoor Unit Data section. Most models will have the breaker size listed.

2. Checking the Technical Brochure

On the same product page, navigate to the Technical Brochure section of the Manuals/Downloads section. Open the Technical Brochure that is given there.

Open the Technical Brochure

From there, scroll the page that provides the technical data of the system. Locate your model, and find the 2 rows that show "Minimum Circuit Ampacity" and "Max Fuse"

Minimum Circuit Ampacity is the lower limit that the breaker size can be, and Max Fuse is the upper limit. Usually, breakers come in sizes that end in 0 or 5, such as 20/25/30/35/40A.

For a more detailed explanation, see below:

Minimum Circuit AmpacityMax Fuse/Breaker
This term refers to the minimum current carrying capacity of the circuit in which the appliance should be installed. It is specified to ensure that the wiring of the circuit can handle the continuous load that the appliance will place on it, thus preventing overheating of the wire, which could cause a fire. Ampacity is a term that combines 'ampere' (a unit of electrical current) and 'capacity', implying the maximum amount of current a conductor can carry before its temperature exceeds a safe limit. This term refers to the maximum rating of the overcurrent protective device, like a fuse or circuit breaker, that should be used in the circuit with the appliance. This rating is given to ensure that in the event of a short circuit or other malfunction causing excessive current, the fuse will blow or the circuit breaker will trip, thus protecting the appliance and the circuit from damage.

The key difference between these two terms is that the "Minimum Circuit Ampacity" is concerned with the normal, continuous operating current of the appliance and the capacity of the circuit wiring, while the "Max Fuse/Breaker" is concerned with protecting the appliance and circuit from abnormal, excessive current conditions. Both of these specifications must be adhered to when installing an electrical appliance to ensure its safe operation.

Simply select the breaker that is compatible with the numbers given here.

In the above example, a 20A or a 25A breaker is acceptable. 

3. Checking and confirming physically on the system itself prior to installation

Even if you have found the information beforehand, it's always best practice to confirm this value once more when installing the system. The figure can be located on the outdoor unit for mini split installations, and both the outdoor and indoor unit for central split installations. 

An example from a mini split outdoor unit

(Refer to #2 regarding the meaning of (Minimum Circuit Ampacity) MCA and Max Fuse.)

Confirming on the system itself is best-practice, because of scenarios where online information may be outdated or inaccurate (in cases where a model was upgraded after ordering, or the wrong product page was looked at).

Note that 120V models require a single-pole breaker, and 240V models require a double-pole breaker. Do not use "Tandem Breakers" on a 240V appliance, it will not work!

Wire Size

Once the breaker size and type is determined, the wire size is simple. In General, wire size will follow the table below. Confirm and comply with your local electrical codes prior to installation. When in doubt, call a licensed electrician.

Breaker SizeWire Size (Based on Copper THHN wire)
15 Amp14 AWG
20 Amp12 AWG
30 Amp10 AWG
40 Amp8 AWG
50 Amp6 AWG

For outdoor unit wiring, it will typically be a 3-conductor wire (L1/L2/G for 240V units and (L/N/G for 120V units). Stranded and unshielded copper wire is recommended.

The amperage rating of the wiring used must match with the breaker amperage. In other words, do not use a higher amperage rated breaker than the amperage rating of the cable used for that circuit.

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