When should the fire fighter at the hydrant charge the supply line?

Charging the supply line at the hydrant should occur upon receiving the signal from the driver/operator. This protocol ensures coordinated efforts between the firefighter at the hydrant and the driver/operator who is managing the water supply.

This timing is crucial because it allows the driver/operator to be ready to handle the flow of water and maintain control, preventing potential hazards such as water hammer or hose whipping that can occur if the line is charged prematurely. It also allows the operator to ensure that everything is in working order, including the apparatus's pump and other critical systems.

By waiting for the signal, all team members are effectively synchronized, which is essential for safety and the efficiency of the emergency response. This organized approach minimizes the risk of accidents and optimizes the firefighting efforts.