A dark screen is not proof of isolation
Equipment can have more than one supply or retain stored energy after normal operation stops.
In 30 seconds
- Learn to distinguish stopped, switched off and safely isolated.
- Identify all energy sources from approved information.
- Electrical work requires competent people and the vessel’s isolation and permit procedures.
Make it concrete
For a classroom diagram, mark normal power, backup power and stored energy in different colours. Do not use the drawing as an isolation checklist.
- 01Sources
- 02Approved isolation
- 03Verified safe condition
Check your understanding
Does pressing a stop button prove all hazardous energy is removed?
- Learn to distinguish stopped, switched off and safely isolated.
- Identify all energy sources from approved information.
- Electrical work requires competent people and the vessel’s isolation and permit procedures.
Go to the source
Sources reviewed: 13.09.2026