What breaker and wire size for an aircon?
1 HP and 1.5 HP: 3.5 mm² THHN (12 AWG) on a 20 A breaker. 2 HP to 2.5 HP: 5.5 mm² on 30 A. Always its own circuit from the panel: the running current is modest (6 A for 1.5 HP) but each start pulls about 40 A for half a second, and a circuit shared with the kitchen is what trips.
Anong breaker at wire ang para sa aircon?
1 HP at 1.5 HP: 3.5 mm² THHN sa 20 A na breaker. 2 HP hanggang 2.5 HP: 5.5 mm² sa 30 A. Laging sariling circuit mula sa panel: maliit lang ang running current (6 A sa 1.5 HP) pero bawat start ay mga 40 A sa kalahating segundo, at ang pinagsasaluhan sa kusina ang nagti-trip.
See it run
Aircon branch circuit: 1.5 HP on 3.5 mm² and a 20 A breaker, on its ownA build with a test sheet: every number on this page is a test you can run.
The numbers
| 1 HP non-inverter | 900 W, 4 A running: 3.5 mm², 20 A |
| 1.5 HP non-inverter | 1300 W, 6 A running, 40 A start: 3.5 mm², 20 A |
| 2 HP non-inverter | 1900 W, 8.5 A running, 55 A start: 5.5 mm², 30 A |
| 2.5 HP | 2300 W, 10 A: 5.5 mm², 30 A |
| Inverter aircon, same HP | same wire and breaker; no start surge |
| Long run over 20 m | go one size up for voltage drop |
Questions
Why not 2.0 mm²? The current is only 6 A.
2.0 mm² PDX is rated 15 A and belongs on a 15 A breaker. The 20 A breaker that rides the start surge needs a 20 A cable, which is 3.5 mm². The breaker protects the cable.
Can the aircon share the outlet circuit?
Not by the code and not in practice: the bench shows a 2 HP unit and two kettles tripping a 20 A breaker in about two minutes.
Does a 20 A breaker trip on the 40 A start?
No. A C-curve breaker’s instant trip is 8 × its rating (160 A for 20 A); 40 A for half a second barely warms its thermal element.
Where is the mm² to AWG table?
On the wire size and voltage drop calculator, with the PEC ratings and the breaker for each size.
More questions
- Will my solar run the aircon at night?
- Why does my aircon trip the inverter when it starts?
- Does grid-tie solar work in a brownout?
- What keeps the Wi-Fi router up in a brownout?
- What breaker and wire size for a water heater?
- How big a solar panel and battery for a piso Wi-Fi?
Brownout backup · Piso Wi-Fi on solar · Solar PV simulator · House wiring simulator