When isolating an electric motor driven pump, what should you do first?

The first step in isolating an electric motor-driven pump is to open the motor breaker. This action ensures that the electrical supply to the motor is interrupted, which is crucial for safety. By cutting off the electrical power, you can prevent the risk of accidental motor start-up during maintenance or troubleshooting activities.

Once the power is disconnected, other isolation procedures, such as closing valves or draining the pump, can be safely performed without the risk of electric shock or unintended equipment operation. Taking this initial step is a key safety measure that protects personnel and equipment during maintenance operations.