Central Air Conditioner Amps & Breaker Size

Central Air Conditioner Power Requirements at a Glance#

A residential central air conditioner runs on a dedicated 240 V circuit and is hardwired at an outdoor disconnect — it never plugs into a receptacle. A 2 to 3-ton condenser draws roughly 15 to 20 A, up to 3,600 to 4,800 W, and sits on a 30 to 40 A breaker; a larger 4 to 5-ton unit pulls 25 to 30 A, up to 6,000 to 7,200 W, and takes a 45 to 60 A breaker. The exact breaker comes from the nameplate, not the running current.

Central Air Conditioner Electrical Specifications#

An outdoor condenser prints two nameplate numbers, a minimum-circuit ampacity and a maximum overcurrent size, and the installer wires to those figures rather than to the running current the compressor actually pulls. A weatherproof pull-out disconnect beside the pad lets a technician kill power at the unit before any service.

Circuit and Breaker Sizing for the Central Air Conditioner#

The breaker and conductors are sized from the two numbers stamped on the condenser nameplate, not from the amps the compressor happens to pull. A 2 to 3-ton unit running at 15 to 20 A is protected by a 30 to 40 A breaker, while a 4 to 5-ton unit at 25 to 30 A steps up to a 45 to 60 A breaker; the wire gauge is chosen to carry that breaker's rating over the run to the pad. The oversize between the running amps and the breaker is deliberate — it covers the compressor's locked-rotor inrush at startup without nuisance tripping. Because the condenser is a 240 V load with no neutral needed for the motor, it always lands on its own two-pole breaker rather than sharing a circuit.

Dedicated Circuit and Disconnect for the Central Air Conditioner#

A central air conditioner must have its own dedicated 240 V branch circuit and a weatherproof disconnect within sight of the outdoor unit, so a technician can kill power at the pad before servicing the compressor. The reason the breaker is picked from the nameplate rather than the running current is that the condenser prints a minimum-circuit ampacity (the smallest conductor it may use) and a maximum overcurrent size (the largest breaker allowed); the installer wires between those bounds. That is why a unit that only draws 25 to 30 A in operation can legitimately sit behind a 45 to 60 A breaker. The furnace or air handler indoors is a separate load on its own circuit and is never combined with the condenser feed.

Installation and Safety Notes for Central Air Conditioner Wiring#

Because the condenser is hardwired rather than cord-and-plug connected, installation is about matching the conductor and the pull-out disconnect to the nameplate rating, not fitting a receptacle. A new central air conditioner circuit is permitted work in almost every jurisdiction: expect a permit and an inspection that checks the disconnect location, the conductor size against the nameplate, and the bonding of the outdoor unit. This is not a homeowner plug-in job — running a new 240 V line to the panel, landing a two-pole breaker, and setting the disconnect is licensed electrician territory, and the HVAC installer will coordinate the low-voltage thermostat wiring separately.

Central Air Conditioner Electrical FAQ#

What breaker fits a residential cooling condenser?#

It depends on the tonnage and the nameplate. A 2 to 3-ton condenser typically sits on a 30 to 40 A breaker at 240 V, and a 4 to 5-ton unit on a 45 to 60 A breaker. Always size to the maximum overcurrent figure printed on the unit, not to the running amps.

Why does the nameplate list both an MCA and an MOCP?#

The minimum-circuit ampacity tells you the smallest conductor the unit may use, and the maximum overcurrent protection sets the largest breaker allowed. Wiring between those two figures is why the breaker is larger than the compressor’s running current.

Can I pick the breaker from running amps alone?#

No. A 4 to 5-ton unit may run at only 25 to 30 A yet require a 45 to 60 A breaker to survive the startup inrush. Sizing from running amps alone would produce nuisance trips and violate the nameplate rating.

Does the outdoor unit require a service disconnect nearby?#

Yes. A weatherproof disconnect must sit within sight of the condenser so power can be cut at the pad before service. It is a code requirement for the 240 V outdoor circuit, not an optional extra.

How much current does a three-ton compressor draw?#

A 2 to 3-ton condenser draws about 15 to 20 A at 240 V in normal operation, for a connected load around 3,600 to 4,800 W. Startup inrush is briefly much higher, which is why the breaker is oversized.

May the furnace and the condenser sit on one circuit?#

No. The cooling condenser and the heating side each need their own dedicated circuit. The electric furnace draws far more amperage on its own feed, and combining the two would overload the shared conductors.