Maximum demand per phase calculator

Assign each load group to L1, L2 or L3. AmpSize applies the AS/NZS 3000:2018 Appendix C demand rule to the loads on each phase on its own. It then reports the demand on every phase and the imbalance between the phases, and names the heaviest loaded phase.

AmpSize spreads the loads across the phases first and applies the demand rule after. The result is therefore the heaviest loaded phase's demand, not an even share of a total. AS/NZS 3000:2018 Paragraphs C2.3.2.2 and C2.4.2 and Note 2 to Table C1 cover the per-phase treatment.

The imbalance is the gap between the heaviest and the lightest phase, as a percent of the heaviest phase. It is an AmpSize figure, not a value from the standard. A warning appears above 20 percent. Move loads between the phases and watch the number fall.

Pick Table C1 for a domestic installation and Table C2 for a non-domestic one. Table C2 then asks whether the occupancy is residential or commercial, because it has a column for each. Both tables hold the AS/NZS 3000:2018 Appendix C data the maximum demand tool uses.

No. The maximum demand tool covers a single installation and blocks of living units. This tool covers the case where you know which phase each load sits on. Both run the same Appendix C engine, so one phase of loads gives the same demand in either tool.