Maintenance switches — safe local isolation of fans for technical interventions

Maintenance switches are mandatory safety equipment in any industrial or commercial installation where fans require periodic intervention. A standard stop button or controller set to zero does not disconnect the motor from the power supply — voltage is still present on the motor windings. Automatic system restart or human error can restart the motor while a technician works on the rotor or belt. The maintenance switch mechanically and visibly disconnects all motor supply phases, with padlock blocking capability (LOTO — Lockout/Tagout) to EN 60947 — the European standard for occupational safety equipment. Mandatory in industrial hall fans, underground car park fans, smoke extraction systems, any ATEX fan, and commercial AHUs with periodic contractual maintenance.