Australia Model Code of Practice: Managing the Risks of Plant in the Workplace 4.2: 4.2 Provide operational controls that are marked, reachable, protected and lockable (r 210)

Operator controls must be identified on the plant to show their nature, function and direction of operation, located so each user can readily and conveniently operate them, located or guarded to prevent unintentional activation, and able to be locked in the off position to enable disconnection from energy sources. Controls should enable fail safe operation, for example a lever that returns to neutral when hand pressure is released; be within easy reach; be readable; move in line with convention; produce the effect only by intentional operation, for example a start control; reduce mistakes, such as requiring two controls together for high risk actions; withstand normal use and environment; sit outside danger zones; be accessible for maintenance; and give the operator good visibility of the whole plant. A speed control should be a lockable stepped control rather than a slider that can be adjusted by accident.