The best way to easily and correctly figure out the right size is to look at the AC’s nameplate. You’ll find the answer to the question, “What size breaker do I need for an AC?” by looking at the information provided in the and “Max Fuse or Breaker” under the “Overcurrent Protective Device” entry in the plate. From there, you can use the standard sizing charts to confirm the correct wire size.
If you want a range, it’s mostly between a minimum of 30 or 40 amps to a maximum of 60 amps. I’ll explain why it’s best to stick to the plate when figuring out what amp breaker for the AC unit to use.
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Why Are ACs Different When It Comes to Determining the Right-sizing Requirements
You’re worried that you may end up going against the Code by following the information on the plate, don’t. Let’s just say air conditioners and most refrigeration systems are “exempt” from it, at least to a certain degree. Ultimately, it’s more that they have their own separate set of guidelines, which is the nameplate.
Take note that all AC systems are required to have these nameplates. Besides revealing the air conditioner circuit breaker size, it also contains the minimum circuit ampacity, which you can use to know the correct wire size to use. It also sports the manufacturer’s name, voltage rating, number of phases, as well as ratings for the ground-fault protective device.
It’s best not to deviate from what the data plate recommends, simply because they’re manufacturer recommendations. Don’t insist on following the Code because you’ll more than likely arrive at the wrong AC breaker size! The same goes for the wire sizes.
Expect Plenty of AC Units to Be Different From One Another Most of the Time
At least, I can say as much from my first-hand experience. Each one has unique requirements and special characteristics that they almost always don’t share the same air conditioner breaker size and other electrical requirements.
This fact could not have been better explained in this Mike Holt video:
It expounds on not only knowing the most appropriate AC unit breaker size but the correct wiring as well. It even takes into consideration the temperature rating of conductors, which it pays to know if you mean to start more serious training related to sizing, wiring, and the National Electrical Code.
To sum up this article on what size breaker do I need for an AC:
- Always choose the information provided by the manufacturer first when pinpointing the right air conditioning circuit breaker size.
- From there, be sure to know the suitable wire size.
- Use sizing charts to confirm the wire size.