What is the purpose of zero energy verification in LOTO?

• A. To ensure the system is ready to energize.
• B. To confirm the energy sources are functioning.
• C. To document energy state.
• D. To ensure there is no stored energy that could cause unexpected energization.

Answer: (D)

The fundamental idea is to confirm that no energy remains in the system after you’ve isolated and locked it out, so nothing can cause the equipment to start or move unexpectedly. Zero energy verification means checking for any stored or residual energy—electrical, hydraulic, pneumatic, mechanical, or even stored thermal energy in springs, capacitors, or accumulators—and ensuring it’s all dissipated or blocked. This final check protects workers by proving the equipment cannot re-energize during maintenance, even if someone else re-energizes the source. It’s not about energizing the system, confirming the energy sources are functioning, or simply documenting the energy state; it’s about guaranteeing there is no energy present that could cause unexpected energization.