Formula variables
- Service amps is the entered service or panel rating used for the screen.
- Known demand kVA should come from measured, billed, engineered, or otherwise documented demand.
- Proposed load kVA is the sum of entered add-load rows.
- Headroom percent is a user-selected margin kept out of the available result.
Assumptions
- Service capacity is calculated from the entered service amps, voltage, and phase.
- Known demand is entered by the user; this is not a dwelling-load or service-load code calculation.
- Proposed load rows convert to kVA before being added to the known demand.
- Utility data, measured demand, equipment nameplates, local authority requirements, and qualified review govern final use.
Examples
200 A, 240 V service screen. A 200 A single-phase service is 48 kVA. With 28 kVA known demand and 14.6 kVA proposed load, projected demand is 42.6 kVA with about 5.4 kVA spare before headroom.
Known-demand workflow. Use this after you have a documented demand value. It does not replace a formal service calculation.