There are four arc flash PPE categories, and the chart people go looking for is really three tables working together. The harder question — the one that decides whether you may use the chart at all — usually gets skipped. This page covers both, as part of our guide to NFPA 70E.
NFPA 70E's table method defines four arc flash PPE categories. Each carries a minimum arc rating, measured in calories per square centimetre:
| PPE category | Minimum arc rating |
|---|---|
| Category 1 | 4 cal/cm² |
| Category 2 | 8 cal/cm² |
| Category 3 | 25 cal/cm² |
| Category 4 | 40 cal/cm² |
The rating is a floor, not a target. Clothing rated above the category minimum is acceptable; clothing rated below it is not, regardless of how it is labelled or what it is made of.
Two other numbers get mixed up with these constantly. 1.2 cal/cm² is not a PPE category — it is the definition of the arc flash boundary, the distance at which incident energy reaches that value. And roughly 2 cal/cm² is the practical threshold at which arc-rated clothing becomes the sensible protection, being about the onset of a curable second-degree burn. Neither is a category rating.
The PPE-category method sits at §130.7(C)(15), and what people call "the arc flash PPE chart" is three separate tables:
These did not renumber for 2027. They appear identically in both the 2024 and 2027 editions.
"Table 130.5(C)" is very widely cited as the PPE-category table. It never was — not in 2027, not in 2024, not in any edition. Copy that cites 130.5(C) for PPE categories was wrong before 2027 and is still wrong now. In 2027, Table 130.5(C)(3) is the likelihood-of-occurrence table, which is a different thing entirely and is discussed below.
NFPA 70E offers two routes to deciding protection: an incident energy analysis, or the table method described here. For a given task a facility uses one or the other — never both. Mixing them is not a conservative compromise; it produces a result that neither method supports.
This is the part that gets skipped, and it is the most consequential thing on this page.
Every row of the AC and DC tables is valid only within its stated parameters: a maximum available fault current, a maximum fault clearing time, and a minimum working distance. Those conditions are not footnotes — they are what the row means.
If your equipment falls outside a row's stated fault current, clearing time or working distance, the table method cannot be used for that task at all. There is no nearest-row approximation and no rounding up a category to compensate. An incident energy analysis is required instead.
In practice this is where the chart is most often misapplied: someone matches the equipment type in the left-hand column, reads across, and never checks whether the system's actual fault current and clearing time fall inside the row's limits.
An equipment label may carry the available incident energy with its working distance, or the arc flash PPE category — but never both for the same equipment. The two come from the two different methods, and showing both signals that the methods have been mixed. It is the single most-missed rule in field labelling.
We cover the full label requirements in how to read an arc flash label.
If you want to walk a specific task rather than read the rules, the PPE category selector steps through the same lookup interactively.
Table 130.7(C)(16) appears throughout older training material as the PPE listing. The fact library clears the (a)/(b)/(c) designations for the 2024 and 2027 editions only, so this page does not date the change to a specific earlier edition. If a document cites (C)(16), it means the same table — renumber the citation rather than treating it as a different requirement.
Similarly, the likelihood table was Table 130.5(C) in 2024 and is Table 130.5(C)(3) in 2027. Superseded, not erroneous.
Not in the current edition. There are four categories, with minimum arc ratings of 4, 8, 25 and 40 cal/cm². Older material referencing a Category 0 predates the current structure.
No — and this is a common and expensive misconception. The category is an outcome of the assessment, not a choice. Over-specifying also carries real costs in heat stress, restricted movement and reduced dexterity, which introduce hazards of their own.
An incident energy analysis is specific to your equipment and gives a number rather than a bracket, which is why it is the basis of most labelling programmes. The table method is a legitimate alternative when the equipment genuinely falls within the table's stated parameters. Outside them it is not an option at all.
The table designations did not — 130.7(C)(15)(a), (b) and (c) appear identically in the 2024 and 2027 editions. The likelihood table was renumbered from 130.5(C) to 130.5(C)(3).
Reference material on the arc flash PPE categories in NFPA 70E. Category contents and the full parameter limits for each row are set out in the tables of the standard itself; consult the current edition. Back to the NFPA 70E guide