The information provided here is only a guide. Always consult the services of a qualified HVAC technician or the owner manual when sizing and installing an AC
If you’ve purchased a 2.5 Ton (~ 28,000 BTU/hr) AC unit and are wondering what size of wire (AWG) or circuit breaker rating (amps) to install,
Or, you have one already installed and want to confirm if they are suitably sized then this post may be of help.
Included in this post are tips to help you select a suitable wire size (AWG) and circuit breaker for your 2.5 Ton air conditioning unit.
Wire Size (AWG) for a 2.5 Ton AC
Assuming the AC has a minimum circuit ampacity of 18.7 amps (shown on its nameplate or in the technical specification section of its manual) then you should be able to use 12/2 AWG wire.
#12 wire has a rated amp rating of approximately 20amps which meets the manufacturer’s recommendation.
Keep in mind that the current draw specifications can vary from one AC model to another based on design and its efficiency rating (EER).
Therefore, always check the AC’s Minimum Circuit Ampacity (MCA) amps rating to guide in selecting the wire size for the AC or contact a qualified HVAC technician for assistance in sizing or installing the AC.
The Danger of Undersizing the Wires
If the wires supplying power to the AC are undersized, they can overheat which poses a safety issue and the AC may not function properly because of the voltage drop that limits how much power is available at the AC.
The Amp Draw
This varies from model to model and as a general guide, 2.5 Ton AC may have a minimum circuit ampacity of 18 – 30 amps at 230V AC.
Always consult the AC’s nameplate to obtain its specific minimum circuit ampacity (MCA).
The Breaker size (Amps)
The AC will usually require a 2-pole circuit breaker rated between 20 – 25 amp at 230V breaker to protect the cables supplying AC power to the AC.
Consult your AC’s nameplate rating for the actual size of the breaker to use for your particular model indicated as the Maximum Overcurrent Protection Device. If the MOPD is say 30 amps then use a 30 amp, 2 -pole circuit breaker.
Closing Thoughts
Check the AC’s nameplate rating s for the minimum circuit ampacity (amps) and maximum overcurrent protection device to select a suitable size of wire (AWG) and circuit breaker respectively or contact a qualified HVAC technician to support you in the sizing or installation of the AC unit.
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