EV maximum demand contribution calculator

Use this calculator when an EV charger group needs one transparent contribution before it is carried into a maximum-demand worksheet, supply-capacity review or switchboard load schedule. It is more specific than a single EV charger load row because it includes charger count and a user-entered diversity factor.

The page does not publish fixed demand factors. That is deliberate. EV charging demand can depend on charger controls, building use, fleet policy, load-management systems, DNSP conditions and project design assumptions. The calculator applies the factor you enter and keeps the source of that factor visible.

Maximum Demand Use Cases

A strong EV demand record names the charger group and the factor source. "Four chargers at 0.45" is weaker than "EV-MANAGED-1, four 22 kW chargers, 0.45 factor from documented load-management basis".

Demand Boundary

This boundary protects the calculator from becoming an unsupported compliance tool. It makes the EV contribution repeatable while leaving the authority for diversity and load management in the project record.

Input Checklist

The diversity factor should not be detached from its source. If a reviewer cannot identify why a factor was used, the safer record is often the full connected load until the project basis is clarified.

Review Workflow

1. Define the EV charger group and reference.
2. Confirm that all chargers in the group can use one kW rating.
3. Enter the charger count as a whole number.
4. Enter the diversity or load-management factor from the project basis.
5. Select phase and voltage basis for the group current estimate.
6. Enter power factor used for kVA/current conversion.
7. Read connected EV load before reading diversified EV load.
8. If the factor is high, confirm the full contribution is intended.
9. If the factor is low, keep load-management or project evidence with the record.
10. Carry the EV contribution into the full maximum-demand or supply-capacity worksheet.

This workflow keeps the page in the right role. It creates an EV row for a broader calculation; it does not replace the broader calculation.

Worked Records

The examples show that the factor is often the most important input. A neat current result is not strong evidence unless the factor source is strong.

Australian Context

Australian EV maximum-demand work sits beside AS/NZS 3000:2018 context, local authority requirements, DNSP requirements where relevant, switchboard capacity, charger controls, manufacturer instructions and the wider installation load schedule. This page does not reproduce fixed Wiring Rules demand factors or network rules.

Use the result with the maximum-demand calculator, supply-capacity planning calculator or project load schedule. If the EV contribution materially changes the load story, the next review should include the whole installation rather than the EV row alone.

Stop Points

• The diversity factor has no documented project, demand or load-management basis.
• Charger ratings differ but are being forced into one group.
• Charger count is uncertain or includes future allowance that should be separated.
• The EV contribution is being treated as whole-installation maximum demand.
• DNSP or switchboard capacity decisions are being made without the broader load schedule.
• Cable sizing or protection selection is being attempted from this EV contribution alone.