When must all brakes and locking devices on a crane or derrick be set?

The requirement for all brakes and locking devices on a crane or derrick to be set when the occupied personnel platform is in a stationary position is crucial for ensuring safety. When the platform is not in motion and is stationary, it's essential to secure the equipment to prevent any accidental movement that could lead to falls or injuries to personnel.

Setting the brakes and locking devices during this state creates a stable environment where workers can perform their tasks without the risk of unexpected shifts or drops. This practice is part of a safety protocol designed to protect individuals working at height and is consistent with standards for safe operation and maintenance of lifting equipment.

The other scenarios, such as when the crane is in operation, the signal person is ready, or when the load is being lifted, do not provide the same level of safety assurance regarding the stability of the platform or machinery. Therefore, focusing on a stationary platform as the time for securing brakes and locking devices highlights a preventative approach to operational safety.