Before a mini-split goes in, the electrical side has to be right. It is the part people overlook when pricing a system, and the part that causes surprises on installation day. Here is what a typical ductless system needs, and what decides whether your panel can handle it.
The basics most systems need
- A dedicated circuit for the outdoor unit. It should not share a circuit with outlets or other appliances.
- The correct voltage. Smaller units may run on 115 volts. Most residential mini-splits, and all larger or multi-zone systems, run on 208 to 230 volts, which needs a double pole breaker.
- A breaker sized from the nameplate. The outdoor unit’s label lists the minimum circuit ampacity and the maximum overcurrent protection. The wire and breaker are chosen from those numbers, not guessed.
- A disconnect near the outdoor unit. Electrical code requires a way to shut off power to air conditioning equipment within sight of it, usually a small disconnect box mounted on the wall next to the unit.
- Interconnect wiring between the outdoor unit and each indoor head, run with the refrigerant lines, as specified by the manufacturer.
Where the indoor heads get their power
On most systems the indoor heads are powered through the interconnect cable from the outdoor unit, so they do not need their own outlets. A few models power the indoor unit separately. Follow the installation manual for your model.
Will my panel handle it?
That depends on the panel’s capacity and how much of it is already used. Questions to ask:
- Is there physical space for a new double pole breaker?
- What is the panel’s rating, and what else draws heavily, such as an electric range, dryer, EV charger or electric water heater?
- Is the panel an older model with known issues or no available parts?
Older homes in Carmichael, Arden-Arcade and Citrus Heights sometimes have small panels that need an upgrade or a load calculation before adding a heat pump or mini-split. Newer homes usually have room for one or two zones.
Permits
Adding a new circuit and installing a mini-split generally requires a permit in the Sacramento area. The inspection checks the wire size, breaker, disconnect and grounding. Unpermitted electrical work can come up in a home sale inspection. See can I install my own HVAC in California.
Common electrical mistakes we see
- Breakers oversized beyond the nameplate maximum
- Undersized wire for the circuit
- No disconnect, or one mounted out of sight of the unit
- Indoor heads wired to the wrong terminals on the interconnect, causing communication errors
- Low voltage and line voltage run in ways that cause interference on communicating systems
Communication errors often show as flashing lights or fault codes on the indoor head. See how to read blinking codes.
DIY mini-splits
Pre-charged DIY kits remove the refrigerant work, but not the electrical work. A dedicated 230 volt circuit and a disconnect are still required, and in most cases that should be done by a licensed electrician or HVAC contractor under a permit.
What we do
We check your panel capacity and space, size the circuit from the nameplate, install the disconnect and pull the permit, so the electrical side is part of the quote rather than a surprise. Pricing is in mini-split installation cost, and sizing in what size mini-split you need. See our ductless mini-split page.
Frequently asked questions
Does a mini-split need its own circuit?
Yes. The outdoor unit should be on a dedicated circuit sized from the unit’s nameplate.
Is a mini-split 110 or 220?
Some small units run on 115 volts. Most residential mini-splits, and all larger and multi-zone systems, run on 208 to 230 volts.
What size breaker does a mini-split need?
It depends on the model. The nameplate lists the minimum circuit ampacity and maximum overcurrent protection, and the breaker and wire are sized from those.
Does a mini-split need a disconnect?
Yes. Code requires a disconnecting means within sight of air conditioning equipment, usually a disconnect box beside the outdoor unit.
Do the indoor heads need outlets?
Usually not. Most indoor heads are powered through the interconnect cable from the outdoor unit. Check your model’s installation manual.
Will I need a panel upgrade for a mini-split?
Sometimes, in older homes with small or full panels. Many newer homes have enough capacity for one or two zones.