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Maximum Demand Calculator

Work out maximum demand for a house or small commercial job.

Table C1 (AS/NZS 3000:2018 Appendix C) - domestic installations only. Single dwelling is single phase only; a 3-phase single dwelling needs manual per-circuit phase assessment, not covered here.

Living units are divided across phases per Note 2 - result is the heaviest loaded phase.

The only per-unit group that stays connected-load-based for blocks (75% every column) - lighting, sockets, ranges and water heaters are worked out directly from the living-unit count above, no separate field needed.

Loads outside these groups (kilns, welders, X-ray equipment and the like) need individual assessment - not covered by this calculator (Table C1, load group (m)).

For guidance only. These calculators are planning aids for licensed electrical workers and inspectors. All results must be independently verified against the current editions of AS/NZS 3000:2018, AS/NZS 3008.1.2, and other applicable standards before being relied on for any installation. CertMate accepts no responsibility or liability for any work carried out, decisions made, or certification issued in reliance on these results. The certifying electrical worker remains solely responsible for compliance with the Electricity (Safety) Regulations 2010 and all applicable New Zealand law.