Mini-Split Electrical Requirements — MCA, MOCP & Disconnects

Mini-splits are wired differently than most appliances: you don’t size the circuit from a generic table, you size it from two numbers stamped on the unit’s nameplate — Minimum Circuit Ampacity (MCA) and Maximum Overcurrent Protection (MOCP). Get those two right, add a disconnect within sight of the outdoor unit, and most of Article 440 falls into place.

Worth knowing

• MCA and MOCP often look odd together — an MCA of 19A with an MOCP of 30A is normal. Wire for 19A (12 AWG typically qualifies), breaker at up to 30A. The compressor’s overload protection is inside the unit; the breaker only handles faults.
• GFCI protection for outdoor HVAC outlets has been a moving target: the requirement in 210.8(F) has been delayed by code action for mini-splits and similar equipment until September 1, 2026, and some states amended it out entirely — ask your local inspector what’s enforced.
• The manufacturer-specified interconnect cable (often 14 AWG, 4-conductor stranded) is part of the listing — substituting random cable is a 110.3(B) violation and a common warranty denial.
• Mount the disconnect beside the unit, not behind it — inspectors read “readily accessible” to mean you can reach it without moving the condenser or squeezing behind refrigerant lines.

Common questions