Electrical Load HVAC

About this app

HVAC Electrical Load & MCA Calculator is the professional tool for HVAC technicians and electricians. Calculate Minimum Circuit Ampacity (MCA) and Maximum Overcurrent Protection (MOCP) sizing per National Electrical Code (NEC) Article 440 requirements for air conditioning equipment installations. EQUIPMENT TYPES SUPPORTED: Split AC Systems - Standard residential split-system air conditioners Package Units - Rooftop and packaged equipment configurations Heat Pumps - Electric heat pump systems with auxiliary heating Mini Split Systems - Ductless mini-split and VRF installations PTAC Units - Packaged terminal AC for apartments and hotels VOLTAGE OPTIONS: Single-Phase: 115V, 208V, 230V (residential and light commercial) Three-Phase: 208V, 230V, 460V (commercial and industrial) ELECTRICAL CALCULATIONS (NEC 440): MCA Sizing - NEC 440.32: 125% of largest motor plus other loads; electric heat at 125% (NEC 424.3(B)) MOCP Selection - NEC 440.22: Maximum overcurrent protection sizing Wire Size Recommendation - AWG per NEC Table 310.16 ampacity Breaker Selection - Standard breaker size selection for protection INPUT PARAMETERS: Compressor RLA (Rated Load Amps) rating LRA (Locked Rotor Amps) startup current Fan FLA (Full Load Amps) Auxiliary heater load current Multiple equipment combinations FEATURES: 100% Offline - No internet connection required for calculations Works in field without cellular coverage English & Spanish language support Dark theme for outdoor visibility OPTIONAL PRO UPGRADE — $2.99 ONE-TIME IN-APP PURCHASE The following features require a separate one-time in-app purchase. They are not required to use the calculator: • Unlimited saved calculation history • PDF export of results • Dark theme • Ad-free experience WHY ELECTRICIANS & HVAC TECHS USE THIS APP: Faster electrical load calculations than manual NEC charts Ensures code-compliant wire and breaker sizing Prevents undersized circuits that risk failure Prevents oversized protection that ignores equipment Cross-check MCA and MOCP calculations Reduces electrician callbacks and callbacks PERFECT FOR: HVAC technicians estimating electrical requirements Electricians sizing circuits for AC equipment AC contractors preparing accurate project bids Electricians qualifying under NEC Article 440 HVAC apprentices learning code requirements Building maintenance engineers planning upgrades NEC Article 440 compliant calculations for safe, code-approved AC installations. Part of HVACTools Suite - professional HVAC technician and AC service tools for field calculations and system diagnostics.

What's new: - MOCP now rounds DOWN to a standard breaker size per NEC 440.22 (it is a maximum; previously rounded up) - Electric heat enters MCA at 125% per NEC 424.3(B) - Wire table aligned to the printed NEC 310.16 75C copper column with 240.4(D) small-conductor limits

Momentum comes from crawler snapshots for the tracked storefront. “Viral growth signal” means unusually fast recent rating gains; it is an indicator, not download data.

1. First observed Oct 16, 2026 · 4:59 PM $0.99