Summary
In short
- De-energizing is the default and the exceptions are narrower than most teams assume. The assessment's main function is to test the justification.
- NFPA 70E is a consensus standard rather than a regulation, and it is how employers demonstrate compliance with OSHA's general electrical safety duties.
- Incident energy depends on how quickly the protective device clears the fault, which depends on whether the device has been maintained. NFPA 70E requires equipment to be properly maintained before energized work.
- NFPA 70B became a Standard rather than a Recommended Practice in 2023, making documented electrical maintenance programmes an enforceable expectation rather than good practice.
- Qualified person status is task and equipment specific. Someone qualified on 480V motor control is not thereby qualified on medium voltage switchgear.
- An arc flash label calculated against a superseded network configuration is more dangerous than no label, because it will be relied upon.
What it is
What it is
What is an electrical safety risk assessment?
An assessment of shock and arc flash hazards for a specific task on specific equipment, establishing whether work can be performed de-energized, and where it cannot, determining the boundaries, the incident energy, the protective equipment and the qualification required of the person performing it.
When is energized work permitted?
Under 29 CFR 1910.333, when de-energizing introduces additional or increased hazards, or is infeasible due to equipment design or operational limitations. Testing, troubleshooting and diagnostics generally qualify. Production schedule, cost and inconvenience do not, and a justification citing them will not survive examination after an incident.
When to use it
When to use it, and when not to
This assessment covers a task on electrical equipment. Several adjacent activities have their own records.
Use it for
- Any task involving exposure to energized electrical conductors or circuit parts
- Determining whether work can be performed de-energized and, where not, justifying the exception
- Establishing shock and arc flash boundaries and required protective equipment for a task
- Assessing qualification requirements for the specific equipment and voltage
- After a network change, protective device replacement or supply alteration affecting fault current
Not for
- The arc flash study, which is an engineering analysis producing incident energy values across the installation
- The energized work permit, which authorises a specific task once this assessment has justified it
- Machine-specific energy control procedures, which cover isolation for servicing
- Electrical safety inspection, which examines condition rather than assessing a task
- Qualified person training records, which evidence the competence this assessment requires
Standards
What it is built against
Electrical safety combines an OSHA work practice standard with a consensus standard that supplies the method.
| Clause | Requirement | Where it lands |
|---|---|---|
| 29 CFR 1910.333(a) | Safety-related work practices to prevent electric shock, with de-energizing as the default | Hazards |
| 29 CFR 1910.333(a)(1) | Energized work only where de-energizing introduces additional hazards or is infeasible by design | Controls |
| 29 CFR 1910.332 | Training for qualified and unqualified persons, defined by task and equipment | Controls |
| 29 CFR 1910.269 | Power generation, transmission and distribution work, including host and contractor information exchange | Header |
| NFPA 70E 110.5 | Risk assessment procedure identifying hazards, estimating likelihood and severity, and determining controls | Hazards |
| NFPA 70E 130.5 | Arc flash risk assessment, incident energy analysis and labelling, reviewed on change | Controls |
| NFPA 70E 205.3 | Equipment maintained in accordance with manufacturer instructions or consensus standards | Controls |
| NFPA 70B (2023 Standard) | Documented electrical maintenance programme with intervals from equipment condition assessment | Controls |
What it does not cover
- The arc flash study, which is engineering analysis across the installation and is triggered by system change.
- The energized work permit, which authorises the task once this assessment has justified it.
- Machine-specific energy control procedures, which cover isolation for servicing rather than energized work.
- Electrical safety inspection, which examines the condition of installations and portable equipment.
- Qualified person determination records, which evidence competence per task and equipment class.
Filling it in
Filling it in well
The assessment turns on one decision and three supporting facts.
Record why de-energizing would introduce additional or increased hazards, or why it is infeasible due to equipment design or operational limitation. If the reason written down is that the line cannot stop, the assessment has established that the work should not proceed energized rather than justifying it.
Incident energy values depend on available fault current and protective device operation, both of which change with transformer changes, new feeders, device replacements and utility supply alterations. Confirm the study post-dates the last such change rather than assuming the label is current.
Incident energy assumes the device clears within its expected time. Where maintenance history is absent, the calculated value understates the exposure. This connects the assessment directly to the maintenance record and is the link most often missing.
Qualified is not a general designation. Record what the person is qualified for, on what basis, and whether it covers the voltage class and equipment type in front of them. For contractors, verify rather than accept, and complete the host and contract employer information exchange in both directions.
Audit findings
Common audit findings
Electrical assessment findings concentrate on justification and on data currency.
| Finding | Clause | What fixes it |
|---|---|---|
| Energized work justified by production schedule or convenience. | 1910.333(a)(1) | Neither is an accepted ground; the assessment should conclude the work waits. |
| Arc flash study predating a network or protective device change. | NFPA 70E 130.5 | Trigger review on any change affecting fault current or device operation. |
| Incident energy relied on with no maintenance history for the protective device. | NFPA 70E 205.3 | Link the maintenance record; an unmaintained device may not clear as modelled. |
| Qualified person status treated as a general designation. | 1910.332 | Record qualification per task and equipment class; voltage classes are not interchangeable. |
| No host and contract employer information exchange for contractor electrical work. | 1910.269(a)(3) | Exchange in both directions and record it; the requirement is explicit. |
| Boundaries not established or not communicated at the point of work. | NFPA 70E 130.4 | Establish and mark the approach and arc flash boundaries for the task. |
| Labels present but not matching the current system. | NFPA 70E 130.5 | Relabel on change; a wrong label is more dangerous than a missing one. |
| Assessment not repeated when the task or equipment differs. | NFPA 70E 110.5 | Assess per task and equipment; a generic electrical assessment covers neither. |
| Electrical maintenance programme undocumented. | NFPA 70B 2023 | Document it; NFPA 70B became a Standard with mandatory language in 2023. |
| Energized work permits issued routinely without trending. | NFPA 70E 130.2 | Trend them; every permit is also a design defect report and the count should fall. |
Worked case
Case in point: the label that was right in 2016
A plant carried arc flash labels across its distribution, applied after an incident energy study. The labels were legible, the PPE categories were understood, and electricians selected protection from them. The programme looked mature.
In the intervening years the site had added a second transformer to support an expansion, replaced two main breakers with a different frame size, and taken a revised supply configuration from the utility. Each change altered available fault current or protective device operation. None triggered a review of the study.
The labels described a network that had not existed for several years. Because they were present and legible, they were trusted, and the PPE selected from them was chosen for an incident energy value that no longer applied.
Definitions
Definitions and key terms
- Incident energy
- The thermal energy an arc flash would deliver at a working distance, determining the PPE category required.
- Arc flash boundary
- The distance at which incident energy equals the threshold for a second-degree burn, marking where protection is required.
- Limited approach boundary
- The distance from an exposed energized conductor within which a shock hazard exists for unqualified persons.
- Qualified person
- Someone with training and demonstrated skills to recognise and avoid the hazards for the specific equipment and task.
- Energized work permit
- Authorisation for work on energized parts, issued only where the narrow justification grounds are met.
- Available fault current
- The current that would flow in a fault, determined by the supply and system impedance and central to incident energy.
- Protective device clearing time
- How quickly a breaker or fuse interrupts a fault, which depends on maintenance and directly affects incident energy.
- Electrical maintenance programme
- The documented programme required by NFPA 70B since it became a Standard in 2023.
FAQ
Frequently asked questions
When can we work energized?+
When de-energizing would introduce additional or increased hazards, or is infeasible due to equipment design or operational limitations. Testing, troubleshooting and diagnostics generally qualify. Production schedule, cost and inconvenience do not. If the justification recorded is that the line cannot stop, the assessment has concluded the work should wait rather than proceed.
Why does maintenance affect the arc flash assessment?+
Because incident energy assumes the protective device clears the fault within its expected time. A breaker never tested or maintained may operate slowly or fail to operate, in which case the energy released exceeds the calculated value and the PPE selected from the label is inadequate. NFPA 70E requires equipment to be maintained, and NFPA 70B became a Standard with mandatory language in 2023.
How often should the arc flash study be reviewed?+
Whenever anything changes that affects available fault current or protective device operation: a transformer addition, a new feeder, a device replacement, a utility supply change. Also on a periodic cycle, because such changes accumulate without anyone flagging them as electrically significant. A label from a superseded configuration is trusted and wrong.
Is NFPA 70E mandatory?+
Not in itself; it is a consensus standard. In practice it is how employers demonstrate they have met OSHA's general electrical safety duties, and it is the benchmark an investigator applies after an incident. Treat the OSHA standard as the obligation and NFPA 70E as the specification for meeting it.
What does qualified actually mean?+
Trained and demonstrably skilled to recognise and avoid the hazards for the specific equipment and task involved. It is not a general status. Someone qualified on 480V motor control may be unqualified on medium voltage switchgear, and the record should state the scope rather than the designation.
The agents
What the agents do with it
The assessment turns on a justification and three facts. What fails is the study that predates the network and the maintenance record nobody linked.
Holds the assessment per task and equipment, tests the energized work justification against the accepted grounds, and issues permits only where it holds.
Links protective device maintenance history to the incident energy assumption, and flags system changes that should trigger study review.
Trends energized work permits, since a flat count indicates nothing is being designed out and each permit is also a design defect report.
Records qualified person scope per equipment class and voltage rather than as a general designation, including for contractors.
This template lives in KnowSafe — safety and compliance. Incidents, hazards, permits, inspections and the critical controls behind them.
Meet KnowSafe→Sources
Sources
- 29 CFR 1910 Subpart S, particularly 1910.332 and 1910.333, OSHA
- 29 CFR 1910.269, electric power generation, transmission and distribution, OSHA
- NFPA 70E, standard for electrical safety in the workplace
- NFPA 70B 2023, standard for electrical equipment maintenance
- CSA Z462, workplace electrical safety (Canada)