How do de-energized work and isolated work differ?

• A. De-energized work requires energy sources to be isolated and tested; isolated work means all energy sources are physically disconnected and stored energy is controlled
• B. They are the same concept
• C. Isolated work means all energy sources are physically disconnected and stored energy is controlled; de-energized work is the same
• D. De-energized work means you can work with energized circuits

Answer: (C)

Both de-energized and isolated work aim to put the equipment in a zero-energy state so it can be worked on safely. Isolated work means all energy sources are physically disconnected and any stored energy is controlled to prevent release. De-energized work means the equipment is not energized and any stored energy has been discharged or secured. In practice, you would shut off power, apply lockout/tagout, disconnect the sources, verify no voltage, and manage stored energy (like discharging capacitors or securing springs) so nothing can re-energize. Because the core goal is to prevent unexpected energization, these conditions are treated as the same safe state in many safety contexts.