In lockout/tagout procedures, what does zero energy mean?

• A. All energy sources are isolated and residual energy is removed or prevented.
• B. Only electrical energy is cut off.
• C. The system remains energized but shielded.
• D. Only hydraulic energy is controlled.

Answer: (A)

The main idea here is to make the equipment truly safe by removing or preventing any release of energy during maintenance. Zero energy means every energy source feeding the machine is isolated and any residual or stored energy is removed, dissipated, or blocked so nothing can move or energize unexpectedly. This includes electrical, mechanical, hydraulic, pneumatic, chemical, and thermal energies, as well as stored energy in springs or charged components. The best answer captures that all energy sources are cut off and any leftover energy is accounted for, ensuring a safe working state. The other statements are too narrow: limiting to electrical energy ignores other forms; keeping the system energized but shielded doesn’t remove stored or residual energy; and focusing only on hydraulic energy misses other potential energy sources.