Electrical Isolation
Electrical isolation is the controlled disconnection and securing of electrical energy so equipment cannot become energized during work.
What this term means in maintenance
Electrical isolation is the controlled disconnection and securing of electrical energy so equipment cannot become energized during work.
Typical steps
Electrical isolation may include:
- Identify supply
- Shut down equipment
- Open isolator or breaker
- Apply lock and tag
- Test the testing device
- Prove dead
- Re-test the device
- Control stored electrical energy
- Earth where required
Practical example
A motor supply is isolated at the correct breaker, locked, tested for absence of voltage, and verified before cable work begins.
Multiple supplies
Control circuits, backup supplies, capacitors, generators, and induced voltage may require additional control.
Authorized personnel
Electrical isolation should be performed and verified by competent authorized persons.
Common mistake
Switching off a local control does not prove that the circuit is electrically isolated.
How this term differs
Electrical Isolation is controlled disconnection and proof of absence of electrical energy. It is related to Energy Isolation, Mechanical Isolation, and Lockout Tagout, but these terms describe different records, measures, roles, strategies, or decisions and should not be used interchangeably.
Related concepts
Related maintenance terms
Keep exploring connected CMMS, reliability, and maintenance planning terms.
Energy Isolation
Energy isolation is the physical separation and control of hazardous energy sources before maintenance, inspection, or entry work.
Lockout Tagout
Lockout tagout, or LOTO, is a controlled process used to isolate hazardous energy and prevent unexpected equipment startup or energy release during work.
Permit to Work
A permit to work is a formal authorization confirming that defined hazards, isolations, precautions, responsibilities, and validity conditions are controlled before high-risk work begins.
Glossary FAQs
- What is electrical isolation?
Controlled disconnection and securing of electrical energy before work.
- What does prove dead mean?
Testing confirms that voltage is absent at the work point using an approved method.
- Are local stop buttons isolation devices?
No. They do not prove electrical energy is disconnected.