What safety step should be taken before replacing a relay on a controller?

Turning the power off and implementing a lockout/tagout procedure is a critical safety step before replacing a relay on a controller. This process ensures that the equipment is completely de-energized and prevents any accidental re-energization while maintenance is being performed. Lockout/tagout involves securing the power source so that it cannot be turned on until the maintenance work is finished, protecting both the technician and the equipment from electrical hazards.

While checking if the relay is functioning, notifying a supervisor, and inspecting the wires are important maintenance steps, they become secondary to ensuring a safe working environment. If power remains on during these operations, there is a significant risk of electric shock or equipment damage. Therefore, the priority must always be to safely isolate the equipment before performing any tasks.