The breaker size isn't a guess. It's on the unit's data plate, as the minimum circuit ampacity and the maximum overcurrent protection. Getting the circuit and breaker right is electrician's work in most places, and it's part of every professional install. Here's what's involved.
Yes, it needs its own circuit
A mini split draws steady power and shouldn't share a circuit with other loads. It gets a dedicated circuit running from your electrical panel to a disconnect box near the outdoor unit, then a short "whip" to the unit itself.
Sharing a circuit risks nuisance trips. Manufacturers' installation instructions call for a dedicated circuit, and the electrical code requires equipment to be installed the way its instructions say.
115V vs 230V
- 115V units (usually the smaller 9k-12k sizes) run on 115-volt power but still need a circuit of their own, sized to the nameplate.
- Most list a minimum circuit ampacity above 15 amps and a 20- or 25-amp maximum breaker, so a spare 15-amp circuit usually won't do.
- The best 115V mini splits guide lists the circuit each pick needs.
- 230V units (most 12k and up) need a dedicated 230-volt circuit with a double-pole breaker. That usually means running a new circuit and confirming your panel has capacity, which is a bigger electrical job than a 115V run.
The breaker size is on the nameplate - don't guess
Every mini split's data plate (and manual) lists two numbers that size the electrical:
- Minimum Circuit Ampacity (MCA): the minimum wire/circuit rating.
- Maximum Overcurrent Protection (MOP): the largest breaker allowed.
The electrician sizes the wire and breaker to these. Most single-zone units land between 15 and 30 amps depending on capacity, and the largest go to 40 amps or more. But use the unit's actual numbers, not a rule of thumb. Oversizing the breaker defeats its protection; undersizing it trips.
What else the electrical involves
- A disconnect box at the outdoor unit, required by code so a tech can safely cut power.
- Panel capacity. A new 230V circuit needs an open double-pole slot and enough service capacity. An older or full panel may need work first.
- Proper wire gauge, sized to the MCA and the run length.
Who does this - and DIY units too
The circuit, breaker, and disconnect are licensed-electrician work in most jurisdictions, even for a DIY mini split. Some jurisdictions let a homeowner pull a permit and wire their own owner-occupied home. If yours does, the work still has to pass inspection.
DIY brands let you do the refrigerant side yourself, but you still need a proper dedicated circuit run to code. Budget for the electrical as part of the job: see installation cost, and how to install a mini split for where the electrical fits in the sequence.
The bottom line
A mini split needs its own dedicated circuit: a 115V circuit for a small unit, or a double-pole 230V circuit for most others. The breaker is sized to the unit's nameplate MCA/MOP, and there's a disconnect at the outdoor unit. It's electrician work in most places, and it's part of every install. Confirm your unit's voltage and requirements in the product finder before you buy.
FAQ
Does a mini split need its own breaker? Yes - a dedicated circuit and breaker, not shared with other outlets or appliances. A 230V unit needs a double-pole breaker; a 115V unit needs a dedicated circuit sized to its nameplate.
What size breaker does a mini split need? Whatever the unit's data plate specifies as its Maximum Overcurrent Protection (MOP). That's commonly 15 to 30 amps depending on capacity, and 20 or 25 amps for most 115V units. Use the nameplate numbers, not a guess.
Can I plug a mini split into a regular outlet? Not into a shared one. Even 115V models need a circuit of their own, and most units of 12k and up are 230V and hardwired. Check your specific unit's electrical data.
Do I need an electrician for a mini split? In most places, yes, for the electrical. The dedicated circuit, breaker, and disconnect are licensed-electrician work, even on a DIY unit where you handle the refrigerant connections yourself. Some jurisdictions allow a homeowner permit for an owner-occupied home.