What is energy isolation in maintenance?

• A. Energizing equipment for testing.
• B. Removing or isolating energy sources to prevent unexpected energization during work.
• C. Labeling energy sources after maintenance.
• D. Measuring energy consumption during operation.

Answer: (B)

In maintenance, energy isolation means removing or isolating all energy sources so the equipment cannot be energized accidentally while work is being done. This protects workers from unexpected startups or releases of stored energy (electrical, hydraulic, pneumatic, mechanical, gravity, etc.). The idea is to completely disable the path to energy and verify that the equipment is dead before any maintenance begins, often using lockout devices or tags to prevent reenergizing.

Energizing equipment for testing describes the opposite of what we want during maintenance. Labeling energy sources after maintenance or during the process is about marking what was shut off or how to reenergize, but it doesn’t by itself stop the energy from flowing. Measuring energy consumption during operation is about monitoring usage, not preventing unexpected energization during work.