deenergization

Deenergization refers to the deliberate removal or separation of energy sources from a system so that it cannot perform its intended function. While most commonly used in electrical engineering, deenergization also applies to other forms of energy such as hydraulic, pneumatic, thermal, or mechanical energy.

Reasons to deenergize include maintenance, testing, fault response, or decommissioning. The process typically involves isolation from energy sources, disconnection from power supplies, and verification that energy has been removed. After isolation, remaining energy must be controlled and dissipated, for example by bleeding hydraulic pressure, discharging capacitors, or grounding conductive parts to prevent stored energy hazards.

Authorized personnel follow documented procedures, often referred to as lockout/tagout or energy-isolation procedures, to ensure that equipment cannot be re-energized while work is underway. These procedures may require physical locks and warning tags, a permit-to-work system, and ongoing verification before any maintenance begins or resumes.

Standards and regulations governing deenergization vary by jurisdiction but commonly emphasize worker safety and energy-control measures. Examples include national or regional electrical safety standards and industry guidelines such as lockout/tagout requirements and electrical safe work practices.

Risks associated with deenergization include residual or stored energy, inadvertent re-energization, and arc flash or shock hazards if energization is not properly controlled. Proper deenergization improves safety during routine maintenance, testing, accidental faults, or decommissioning, and is a core practice in electrical and process industries.