Skip to content
Fire alarm commissioning and electrical test tools on a workbench

Find the lower device-count limit

Circuit Loading Calculator

Compare the panel-output and worst-case end-of-line voltage-drop constraints.

Method context

BS 5839-1:2025 Clauses 11, 15 and 24

The implementation follows the current Swift calculator in the Fire Regs Pro project. It is an estimate for revision and preliminary checking.

Check before use: Confirm the current standard, project specification, manufacturer data, environmental derating and actual site measurements. A browser result is not a design certificate.