Central AC units typically draw 15-25 amps depending on size (2-5 ton). A 3-ton unit typically draws about 18-20 amps.
| Recommended wire | 10/2 with ground |
| Breaker | 30A double-pole |
| Voltage | 240V |
| Typical amperage | 20A |
| Circuit amperage | 30A |
| NEC reference | NEC 440 |
| Max recommended distance | About 145 feet one-way for 3% drop at 20A |
AC units have high starting (LRA) currents that can be 3-5× running amps. The breaker and wire must handle the maximum circuit ampacity marked on the unit's nameplate. Check the MCA (Minimum Circuit Ampacity) and MOP (Maximum Overcurrent Protection) on the data plate.
Central AC wire size depends on the unit's Minimum Circuit Ampacity (MCA) on the nameplate. Most 2–3 ton units (18–25A MCA) use 10 AWG copper on a 30A double-pole breaker. Larger 4–5 ton units (30–40A MCA) may require 8 AWG or 6 AWG copper.
MCA (Minimum Circuit Ampacity) is the minimum wire ampacity required for the AC unit's supply circuit. Always size the wire and breaker to meet or exceed the MCA. Also check the MOCP (Maximum Overcurrent Protection) rating, which sets the maximum breaker size.
No — central air conditioners must have a dedicated circuit. Other loads cannot share the AC circuit. A disconnect switch (non-fused or fused) must also be installed near the outdoor condenser unit within sight of the unit.
Mini-split wire size varies by unit capacity. Small 9,000–12,000 BTU mini-splits (under 15A MCA) can use 12 AWG copper on a 20A circuit. Larger 18,000–24,000 BTU units with 20–25A MCA typically use 10 AWG copper on a 30A circuit.