NFPA 70E 130.5 · five-year review
Arc Flash Study Updates & 5-Year Reviews
If your arc flash study is more than five years old, predates a system change, or was calculated to IEEE 1584-2002, your labels may be wrong. Send us the report and a licensed PE will tell you whether you need an update or a new study, and what each would cost.
Six signs your arc flash study is out of date
Any one of these can make the numbers on your labels wrong. That’s the real risk, not the paperwork: a worker selects PPE from the label.
It's been five years
NFPA 70E 130.5 requires the arc flash risk assessment to be reviewed at least every five years. The study date is the first thing an insurer, auditor or corporate EHS reviewer checks.
The utility changed something
A new or larger utility transformer can raise available fault current at your service without you being told. Ask the utility for a current fault-current letter. If it differs from the study, the labels may be wrong.
You added or replaced equipment
A new service, generator, transformer, MCC or large motor changes fault current and clearing times upstream and down. Labels downstream of the change may no longer be valid.
Breaker settings were changed
Incident energy depends on clearing time. A settings change made during troubleshooting or a gear replacement can quietly make several labels wrong.
It was done to IEEE 1584-2002
The 2018 edition changed the model itself: electrode configuration and enclosure size now affect the result. Values move in both directions, and some buses go up.
Nobody can find the model
If the original firm kept the model, or the report has no assumptions section, an update isn't really possible. You're buying a new study either way. It's better to know that before you request quotes.
Update or redo? How we decide
An update is usually enough when…
The native model (SKM or equivalent) is available, the report documents its assumptions, the system changes are limited and known, and the study already uses IEEE 1584-2018. We field-verify the changes, re-run every scenario and re-label only what changed.
A new study is usually cheaper when…
There's no model or the vendor won't release it, the study uses IEEE 1584-2002, nobody documented the changes, or a walk-down finds the one-line no longer matches the gear. Patching a model you can't trust costs more than rebuilding it.
We recalculated a hospital’s 480Y/277 V system under both editions. Most buses went up, one by 8.35 cal/cm², while the main switchboard dropped from 34.56 to 23.56 cal/cm². Read the case study
Field verification of changed equipment, a fresh utility fault letter, re-run short circuit, coordination and arc flash scenarios, a revised sealed report, and new labels where values changed.
Send us your existing study
Tell us the study date, who performed it, the IEEE 1584 edition if you know it, and what has changed since. A PE will reply with an update-or-redo recommendation and a fixed fee. You can email the PDF to us after you submit.
Not sure what a complete study should contain? Compare yours to our sample report
Arc flash study update FAQ
NFPA 70E 130.5 requires the arc flash risk assessment to be reviewed at least every five years, and whenever a modification or renovation could affect the results. Utility transformer changes, added generation, equipment replacements and protective device setting changes all qualify.
NFPA 70E's Informative Annex D lists IEEE 1584 as an incident energy method, and the 2018 edition is the current one. At the five-year review, recalculating under 2018 is the defensible choice. In our hospital comparison, most buses went up, one by 8.35 cal/cm², while the main switchboard dropped. A label that was adequate can become inadequate.
Usually, if the model exists and is trustworthy. Field verification of the changed areas plus re-modeling costs less than full data collection. If the model is missing or built to the 2002 method, a new study is often close in price and more reliable.
Yes, if we can get the native model files and the report. We verify the model against the field before we rely on it. If it doesn't match, we tell you and price the difference rather than build on bad data.
Only the labels whose values changed, plus any that are damaged or unreadable. Each label must carry the study date, so updated equipment gets new labels with the new date.
Find out if your study is still valid
A 10-minute call with a licensed PE — we'll tell you what your study should cover and what it should cost. No obligation.