An arc flash study isn’t a one-and-done document. The moment you change a breaker, add a transformer, or the utility adjusts the available fault current at your service, the incident-energy numbers on your equipment labels may no longer be accurate and inaccurate labels put workers at risk. So how often should an arc flash study be updated? The short answer: at least every five years, and sooner whenever your electrical system changes.
What is an arc flash study?
An arc flash study — also called an incident energy analysis calculates how much thermal energy a worker could be exposed to at each point in your electrical system during an arcing fault. It produces the arc flash boundary, the required personal protective equipment (PPE), and the warning labels applied to your equipment. The calculations are performed using the IEEE 1584 method within the risk-assessment framework of NFPA 70E.
How often does NFPA 70E require an update?
NFPA 70E, Standard for Electrical Safety in the Workplace, section 130.5, requires that the arc flash risk assessment be reviewed at least once every five years. That five-year mark is the outer limit — not a target to coast toward. If anything about your electrical distribution system changes in the meantime, the study must be reviewed and updated when that change occurs, not at the next five-year interval.
Changes that trigger an update before five years
Review your study whenever any of the following happens:
- New equipment is added or existing equipment is replaced — transformers, switchgear, breakers, or panels
- Protective device settings, ratings, or types change
- The utility changes the available fault current at your service — a common and often overlooked trigger
- Major loads are added or removed, or the distribution system is reconfigured
- Equipment is relocated, or the facility is expanded
- Testing or maintenance reveals a protective device is no longer operating within spec
Any of these can move incident-energy values up or down, which changes both the PPE requirements and the arc flash boundary printed on your labels.
What happens if your study is out of date?
Outdated labels are both a compliance and a safety problem. OSHA recognizes NFPA 70E as the consensus industry standard for electrical safety, so an inaccurate or missing study can translate into OSHA exposure under the General Duty Clause after an incident. More importantly, workers may be wearing the wrong PPE for the actual hazard — either under-protected against a higher-energy event, or so over-protected that the task becomes impractical. Insurers and auditors increasingly ask to see a current study as well.
How to keep your arc flash study current
Treat the study as a living document. Keep a single-line diagram that’s updated as changes are made, log every modification to protective devices, and build an arc flash review into your change-management process so updates happen at the moment of change. Pairing the study with regular NFPA 70E electrical safety training ensures the people reading the labels actually understand them. When it’s time to refresh, an incident energy analysis rebuilds the model with your current system data.
The bottom line
If your last arc flash study is approaching five years — or you’ve changed equipment since it’s time for a review. You can read the current NFPA 70E standard on the NFPA website, then contact Bowtie Engineering to update your study before your labels fall out of date.