Low Arc Flash Labels: A Hidden Hazard and Liability for Employers

Frequently Asked Questions

Can a low arc flash label be more dangerous than no label?

Yes. If the label is based on bad or outdated analysis, workers may choose lighter PPE, spend less time planning, or work closer to energized equipment than the real hazard allows.

What usually causes an arc flash label to show a hazard that is too low?

Common causes include outdated one-line diagrams, missing field verification, incorrect protective device settings, wrong clearing-time assumptions, and failure to review the study after system changes. Generic methods used without checking actual equipment and operating conditions can also make labels misleading.

How can I tell if our arc flash labels may not be reliable?

Red flags include labels that do not match the equipment in the field, recent setting changes, added generators or new equipment, outdated one-lines, and no clear explanation for how the incident energy was calculated. If the study date is old or there was no documented review after major changes, the labels should be checked.

What should EHS or operations leaders do if they think labels may be inaccurate?

Review the electrical system change history, compare labels to current field conditions and one-lines, and ask for the study basis and assumptions. Start with high-consequence equipment and train supervisors and qualified workers that labels support planning but do not replace job planning and verification.

Why are inaccurate low arc flash labels a compliance and legal risk for employers?

They can show that the hazard assessment process was weak, outdated, or not verified against actual conditions. That can create exposure in incident reviews, audits, insurance reviews, customer reviews, and other due-diligence checks.