Calculate electrical maximum demand for non-domestic installations per AS/NZS 3000 Table C2. Apply diversity factors, determine cable sizing, and select main switch ratings.
Add each load type and connected power. Diversity factors are applied automatically per AS/NZS 3000 Table C2.
Add each electrical load type with its connected power in kW. The calculator applies the appropriate diversity factor from AS/NZS 3000 Table C2.
Not all loads operate simultaneously. Diversity factors reduce the total to a realistic maximum demand. Larger loads like HVAC get 100% for the first unit, 50% for additional.
The maximum demand current determines the minimum cable cross-section and main switch rating needed. Always verify with a licensed electrician.
Reference: Maximum demand per AS/NZS 3000:2018 Appendix C, Table C2 (non-domestic). Diversity factors are approximate. Cable sizes are indicative only and must account for installation conditions, voltage drop, and temperature derating.
CCC Engineering delivers complete electrical design packages, including maximum demand assessments, distribution board schedules, cable sizing, and full IFC documentation.
This maximum demand calculator helps electrical engineers, builders, and project managers estimate the electrical maximum demand for non-domestic installations. Add each electrical load type with its connected power in kilowatts, and the calculator applies diversity factors automatically per AS/NZS 3000:2018 Appendix C, Table C2. The results include the after-diversity maximum demand, apparent power in kVA, maximum demand current, and recommended cable and main switch sizes.
The calculator follows the diversity method from AS/NZS 3000, where different load types are reduced by standard factors to reflect real-world usage patterns. Lighting and water heating are applied at 100%, while additional HVAC units and socket outlets use 50%. The supply configuration (single phase 230V or three phase 415V) and power factor are adjustable to match your project requirements. Cable sizing recommendations are based on standard current ratings and should be verified against AS/NZS 3008 for the specific installation conditions.
This tool provides indicative maximum demand estimates suitable for early design stages and feasibility assessments. Final maximum demand calculations for construction documentation must account for actual equipment schedules, motor starting currents, future load allowances, and specific installation conditions including cable derating, voltage drop, and fault current. Always have the design verified by a licensed electrician or qualified electrical engineer.