MRCOOL DIY® Electrical Requirements: Breaker Size, Wire Gauge and 115V vs 230V
- 9K and 12K run on 115V. 18K, 24K and 36K need 230V.
- Every size needs its own dedicated circuit and an outdoor disconnect.
- MRCOOL requires electrical work by a qualified electrician.
The mechanical side of a MRCOOL DIY® install is yours. The power circuit is the one piece MRCOOL's manual says a qualified electrician has to do, and we agree. Here's everything you need to plan it and get a fair quote.
Electrical specs by size (DIY® 5th Gen single-zone)
| Size | Voltage | Min. circuit ampacity | Max breaker | Typical wire |
|---|---|---|---|---|
| 9K | 115V | 18 A | 20 A | 12 AWG |
| 12K | 115V | 18 A | 20 A | 12 AWG |
| 18K | 230V | 18 A | 20 A | 12 AWG |
| 24K | 230V | 24 A | 25 A | 10 AWG |
| 36K | 230V | 33 A | 35 A | 10 AWG |
Numbers are from MRCOOL's 5th Gen single-zone manual and spec sheets. Wire size depends on run length and local code, so your electrician and inspector make the final call. Always check the nameplate on your condenser.
Is MRCOOL DIY® 110V or 220V?
Both. The 9K and 12K come in 115V versions (the same voltage as a regular outlet, but on a dedicated hardwired circuit, not plugged in). That's handy for garages, sheds and older homes without a spare 240V slot. The 18K and up are 230V only. MRCOOL also makes 230V versions of the smaller indoor units for multi-zone systems.
What power actually goes where
- Panel → disconnect → condenser. The electrician runs a dedicated breaker to an outdoor disconnect within sight of the condenser, then a short whip to the unit.
- Condenser → indoor unit. This is the DIYPRO® cable that comes in the box. It powers and talks to the indoor unit. You plug it in and land its numbered wires on the condenser's terminal block. No separate indoor circuit.
MRCOOL · 6:17MRCOOL DIY® installation guide (wiring section near the end)What to hand your electrician
- The model number and nameplate photo of the condenser
- The table above (MCA and max breaker)
- Where the condenser sits and the distance back to your panel
- Whether you need a surge protector (MRCOOL recommends one on fixed wiring)
Common questions
Can I plug a 115V MRCOOL into an outlet?
No. Even the 115V models are hardwired on a dedicated 20 A circuit with a disconnect.
Can two mini splits share a circuit?
No. MRCOOL says not to share the power supply with other appliances. Each condenser gets its own circuit.
My panel is full. Now what?
A 115V 9K or 12K needs only a single-pole slot, and an electrician may be able to free space with tandem breakers where allowed. Ask before you choose a 230V size.
Get the DIY Mini Split Install Handbook
All 13 steps, the clearance, torque, wiring and line set tables, QR codes to every MRCOOL video, a sign-off checklist, and a 10% off code for your system.
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