De-energizing is always the default when electrical work is performed — opening the circuit is the safe starting point for any task, not an option to weigh against convenience. There are, however, narrow cases where energized work is justified, and NFPA 70E requires those cases to go through a formal energized electrical work permit before anyone touches live equipment.
When a permit is actually required
A permit is required whenever the work cannot or will not be done in an electrically safe work condition. That's a high bar. De-energizing is the preferred approach in essentially every case; energized work is only authorized when de-energizing would create a greater hazard — cutting power to life-safety systems, for instance — or when the equipment's design or operational continuity makes de-energizing genuinely infeasible. "It would take longer to de-energize" is not, on its own, one of those justifications.
Who has to sign it
The permit requires dual authorization: it must be reviewed and signed by both a qualified electrical worker who will perform the work, and a management representative with responsible authority. The qualified worker confirms the technical scope and safety readiness from the field side; the management signature exists specifically so business pressure alone can't push a worker into energized work without an independent check. Neither signature substitutes for the other, and neither can be added after the fact.
What the permit has to document
A complete permit records the circuit, equipment, and location; the justification for why the work must be performed energized; a description of the work itself; the results of the shock and arc flash hazard analysis; the required PPE for both shock and arc flash; the safety precautions and procedures to be followed; evidence that qualified workers will be performing the task; and the authorization signatures. It's a live document — created before the job starts, and kept on site for the duration of the work, not filed away as a formality.
The diagnostics exception
NFPA 70E carves out a limited exception for diagnostic work — testing, troubleshooting, voltage measurement — that requires the circuit to be energized by its very nature. You can't verify a live voltage reading on a de-energized circuit. Properly rated test equipment, correct PPE, and qualified personnel are still required, and the exception simplifies the permit process rather than eliminating it.
Walking through the decision
The same logic that governs the permit shows up as a recurring exam scenario: can the work be done de-energized? If yes, it must be. If de-energizing would create a greater hazard or is genuinely infeasible, document the justification, obtain the permit with both required signatures, and confirm the PPE matches the arc flash and shock hazard analysis — only then does energized work proceed. Skipping straight to "get the permit" without first ruling out de-energizing is the most common way this gets tested wrong.
For the full trigger conditions and permit layout, review the ArcReady Study Guide §7, with practice questions in the Exam Companion.