What is ordered to be placed at the control of the switch as soon as a switch is opened?

When a switch is opened, it is critical to ensure that it is secured to prevent accidental re-energization. A hold card is used in this situation, as it serves as a visual indication that the switch is in an open position and is being worked on. The presence of a hold card specifically communicates to all personnel that the equipment linked to that switch should not be operated.

The hold card acts not only as a marker for an open switch but also as a safety protocol to make sure that everyone involved in the maintenance or testing of the system is aware of the status of the switch. It is an essential part of lockout/tagout procedures designed to protect workers from electrical hazards.

Other items like a lock box, safety flag, or warning sign may have their uses in different contexts, but the hold card directly addresses the need for communication and ensures that operational safety protocols are being followed when a switch is manipulated.