What must be done before performing maintenance on mobile equipment to ensure it cannot move?

What must be done before performing maintenance on mobile equipment to ensure it cannot move?

• A. Remove keys
• B. Power off and block against motion
• C. Engage parking brake
• D. Apply chocks and wedges

Answer: (B)

Preventing movement of mobile equipment during maintenance requires removing all potential sources of energy and physically restraining the machine. Powering off cuts electrical and hydraulic power and stops active systems, so the machine can’t move due to energized controls or unexpected reactivation. Blocking against motion adds a physical barrier that prevents any remaining movement, even if a control is actuated or a residual force could cause movement. Together, these steps create a reliable safeguard that minimizes the risk of the equipment moving while someone is working on it. Relying on removing keys only reduces the chance of starting, but it doesn’t guarantee that the machine won’t move if a control is activated or if someone bypasses that measure. Engaging the parking brake might help on some units but can fail or not apply to every movement direction. Using chocks and wedges alone helps prevent rolling but may not address all movements, especially on inclined surfaces or in systems with residual pressures. The dual approach of powering down and blocking against motion provides the most dependable protection during maintenance.

Preventing movement of mobile equipment during maintenance requires removing all potential sources of energy and physically restraining the machine. Powering off cuts electrical and hydraulic power and stops active systems, so the machine can’t move due to energized controls or unexpected reactivation. Blocking against motion adds a physical barrier that prevents any remaining movement, even if a control is actuated or a residual force could cause movement. Together, these steps create a reliable safeguard that minimizes the risk of the equipment moving while someone is working on it.

Relying on removing keys only reduces the chance of starting, but it doesn’t guarantee that the machine won’t move if a control is activated or if someone bypasses that measure. Engaging the parking brake might help on some units but can fail or not apply to every movement direction. Using chocks and wedges alone helps prevent rolling but may not address all movements, especially on inclined surfaces or in systems with residual pressures. The dual approach of powering down and blocking against motion provides the most dependable protection during maintenance.