Warning devices on powered mobile plant

Guidance for employers, self-employed persons and people who have management and control of a workplace (legal duty holders) about the unsafe work practice of deactivating warning devices on powered mobile plant.



Earlier this year an employee was hit and injured by a reversing excavator. The excavator had a motion alarm but it had been switched off via a switch located in the cab.

Investigation into industry practice revealed that some items of powered mobile plant are being fitted with a switch that turns the motion alarm off. This switch appears to be aimed at reducing the environmental impact (noise) when travelling and/or operating near built up or residential areas. These switches present a risk when the warning device does not work as intended, for example, when:

  • the switch is turned off by mistake; or
  • the switch is not turned back on when it should be.

Control measures

Legal duty holders must ensure that powered mobile plant that has a likelihood of hitting pedestrians or other powered mobile plant is fitted with a warning device, for example a motion alarm, that will warn persons who may be at risk from the movement of the plant.

Deactivation switches fitted to mobile plant are not recommended because they stop motion alarms from sounding to warn people who may be at risk from the movement of the plant. If deactivation switches are fitted they should be set up so that the alarm automatically reactivates (the switch resets) when the item of plant ceases to travel.

Employers should ensure pre-start checks of powered mobile plant are undertaken by operators in accordance with manufacturers' instructions. If warning devices are faulty, remove the powered mobile plant from service until the warning device is repaired or replaced.

Further information