Renovation · CEC Section 28 (Motors & HVAC Equipment)

Heat Pump / AC Load Calculator

Size circuit breaker ratings, Minimum Circuit Ampacity (MCA), and Max Overcurrent Protective Device (MOPD) for central heat pumps and mini-split units.

1. HVAC Nameplate Details

Equipment Type

Minimum Circuit Ampacity (MCA from nameplate)

Max Overcurrent Protection (MOPD / Max Fuse/Breaker)

2. Circuit & Wire Sizing

CEC Section 28 HVAC

RECOMMENDED BREAKER SIZE

30A 2-Pole Breaker

MINIMUM COPPER NMD90 WIRE

10/2 Copper Wire (30A rating)

OUTDOOR DISCONNECT REQUIREMENT

30A Fused / Non-Fused Disconnect

CEC Rule 28-604: An outdoor weatherproof disconnect switch must be installed within sight of the heat pump compressor unit.

HVAC Sizing Rules

Wire gauge is sized strictly according to Minimum Circuit Ampacity (MCA).
Breaker size is selected up to the Maximum Overcurrent Protective Device (MOPD) stamped on unit nameplate.
It is normal under CEC Section 28 for breaker rating to be larger than wire ampacity due to motor inrush starting currents.

Typical AC/heat-pump electrical data

Nameplate values vary — always use the unit's rated load amps (RLA) and min. circuit ampacity (MCA).

Capacity	Typical MCA	Typical breaker	Wire (Cu)
1.5 ton	14–18 A	20 A	12 AWG
2 ton	17–22 A	25–30 A	10 AWG
2.5 ton	20–25 A	30 A	10 AWG
3 ton	24–30 A	35–40 A	8–10 AWG
4 ton	30–37 A	40–50 A	8–6 AWG

Condensers need a dedicated circuit, outdoor-rated disconnect within sight, and breaker sized to the label's max overcurrent.

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