If you're shopping for CAT 2 FR clothing, here's the short answer: "CAT 2" means the garment is part of a PPE clothing system rated to handle an arc-flash hazard requiring an arc rating of at least 8 cal/cm². "CAT 1" handles a lighter hazard (at least 4 cal/cm²). The category number is set by the hazard you're working on — not by personal preference — and your employer's arc-flash risk assessment is what tells you which category a given task falls into. The "CAT" levels (PPE Categories 1-4) come from NFPA 70E, the standard for electrical safety in the workplace, and they define how much arc-flash protection your clothing system must provide.
Key Takeaways
- CAT is about the hazard, not the garment: the PPE Category (1-4) is assigned to a task by an arc-flash risk assessment; you then match clothing whose arc rating meets that category's minimum.
- The four minimums (cal/cm²): CAT 1 ≥ 4, CAT 2 ≥ 8, CAT 3 ≥ 25, CAT 4 ≥ 40. Higher category = more thermal energy the system must withstand.
- CAT 1 vs CAT 2: same idea, different energy. CAT 2 (≥ 8 cal/cm²) is the most common everyday electrical-work category and usually means a single arc-rated layer that hits the number.
- "HRC" is the old name: the 2015 edition of NFPA 70E renamed Hazard/Risk Category (HRC) to PPE Category and dropped the old "HRC 0," leaving CAT 1-4. If you searched "HRC 2," you want "CAT 2."
- The rating lives on the tag: a garment's arc rating (ATPV or EBT, in cal/cm²) is what proves it qualifies for a category — not the word "FR" alone. All arc-rated clothing is FR, but not all FR is arc-rated.
What a "CAT level" actually is
A PPE Category is a shorthand for "how much arc-flash energy your clothing system needs to survive." NFPA 70E — the standard covering electrical safety in the workplace — defines four of them, CAT 1 through CAT 4, each tied to a minimum arc rating measured in calories per square centimeter (cal/cm²). The category is assigned to the job, not picked off a shelf. Either an engineering arc-flash study calculates the incident energy for a specific piece of equipment, or your employer uses the standard's category method to classify the task. Out of that comes a category, and the category tells you the minimum arc rating your clothing must carry.
That's the part people get backwards. You don't decide you're "a CAT 2 guy." The panel you're about to open, the available fault current, the clearing time of the protective device — those decide the category. Your job is to wear a clothing system whose arc rating meets or beats the minimum for that category. Read your site's arc-flash labels and your employer's PPE program; they're the authority on which category applies to what you're touching.
The four CAT levels and their minimum arc ratings
Here's the whole ladder in one place. The cal/cm² figures are the minimum arc rating the clothing system must provide for that category, per NFPA 70E.
| PPE Category | Old HRC name | Minimum arc rating | What it generally means |
|---|---|---|---|
| CAT 1 | HRC 1 | ≥ 4 cal/cm² | Lightest arc-rated requirement — a single arc-rated layer that meets the number. |
| CAT 2 | HRC 2 | ≥ 8 cal/cm² | The most common everyday electrical-work level; typically one arc-rated layer rated to the number. |
| CAT 3 | HRC 3 | ≥ 25 cal/cm² | Higher-energy work; usually achieved by layering arc-rated garments (e.g., a system, not one shirt). |
| CAT 4 | HRC 4 | ≥ 40 cal/cm² | The highest category; an arc-rated flash suit / multi-layer system. |
Two things to notice. First, the jump from CAT 2 to CAT 3 is big — 8 to 25 cal/cm² — which is why CAT 3 and CAT 4 generally aren't one garment but a system of arc-rated layers whose combined, tested rating hits the number. Don't assume two CAT 2 shirts add up to CAT 3 or 4; arc ratings don't simply stack, and only the tested rating of the layered system counts. Second, every one of these minimums is an arc rating — a number that comes from testing the fabric, not from the garment merely being flame-resistant.
CAT 1 vs CAT 2: the question everyone asks
This is the comparison I see most, so let's be plain about it. CAT 1 and CAT 2 work exactly the same way — both are arc-flash categories, both call for an arc rating in cal/cm². The only difference is the energy level. CAT 1 requires a clothing system rated to at least 4 cal/cm²; CAT 2 requires at least 8 cal/cm². CAT 2 is asking your clothing to handle roughly twice the thermal energy.
"Which do I need?" isn't yours to choose — the hazard chooses. If your task is assessed as CAT 2, a CAT 1 garment (rated to only 4 cal/cm²) is under-protective for that work, full stop. Going the other way is fine on the protection side: a garment rated to 8 cal/cm² or higher satisfies a CAT 1 task. Plenty of electrical workers land on a solid arc-rated daily layer rated to 8 cal/cm² because it covers both CAT 1 and CAT 2 tasks with one garment. But "I'll just wear something heavier to be safe" has limits too — over-layering can add heat stress and mobility problems, and it still has to be arc-rated clothing, not random heavy cotton. Match the category your assessment gives you.
"HRC" vs "CAT": why the terms changed
If you grew up calling these "HRC levels," you're not wrong — you're just using the older vocabulary. The terms used to be Hazard/Risk Category (HRC). The 2015 edition of NFPA 70E renamed them to PPE Category and, in the same edition, dropped the old "HRC 0." So the modern ladder is CAT 1 through CAT 4, with no zero.
The numbers most people care about — the minimum arc ratings — carry across the rename cleanly: HRC 2 and CAT 2 both mean a clothing system rated to at least 8 cal/cm². So when you find a forum post or an old spec sheet saying "HRC 2," read it as "CAT 2." A lot of retailer listings and garment tags still print "HRC" or "CAT/HRC" together precisely because both terms are out in the world. The protection requirement didn't change; the label did.
How a garment proves it meets a category
A category is met by the arc rating, and the arc rating is a tested number — not the word "FR." Arc-rated fabric is tested and assigned a rating in cal/cm², expressed as either ATPV (arc thermal performance value) or EBT (energy break-open threshold). When both are determined, the garment's arc rating is the lower of the two, and higher is more protective. That single cal/cm² number is what you compare against the category minimum.
This is where the most dangerous shortcut lives. All arc-rated clothing is flame-resistant, but not all flame-resistant clothing is arc-rated. A shirt can be genuinely FR — even certified to NFPA 2112, the flash-fire garment standard used in oil and gas — and still carry no arc rating at all. For an arc-flash hazard, "FR" alone doesn't qualify for any CAT level; you need an arc rating in cal/cm². So to confirm a garment fits your category: find the arc rating printed on the tag or listing (it should reference ASTM F1506, the FR and arc-rated apparel spec for electrical workers), check that the cal/cm² number meets or beats your category minimum, and be skeptical of anything that says "flame resistant" but states no arc rating and no standard.
Frequently Asked Questions
What is CAT 2 FR clothing?
CAT 2 FR clothing is arc-rated clothing meeting the PPE Category 2 requirement from NFPA 70E: a clothing system with an arc rating of at least 8 cal/cm². The category is assigned to a task by an arc-flash risk assessment, and you match clothing whose tested arc rating (ATPV or EBT, in cal/cm²) meets that minimum. CAT 2 is the most common everyday electrical-work category.
What's the difference between CAT 1 and CAT 2?
Both are arc-flash PPE categories; the difference is the energy level. CAT 1 requires a clothing system rated to at least 4 cal/cm², and CAT 2 requires at least 8 cal/cm² — about twice the thermal energy. You don't choose your category; your task's arc-flash assessment assigns it. A garment rated to 8 cal/cm² or more satisfies both a CAT 1 and a CAT 2 task.
Is HRC the same as CAT?
Essentially, yes. "HRC" (Hazard/Risk Category) is the older name; the 2015 edition of NFPA 70E renamed it to "PPE Category" and dropped the old HRC 0, leaving CAT 1-4. The minimum arc ratings carry across unchanged — HRC 2 and CAT 2 both mean a system rated to at least 8 cal/cm². If you searched "HRC 2," you want "CAT 2."
What arc rating does each CAT level need?
Per NFPA 70E, the minimum clothing arc ratings are CAT 1 ≥ 4 cal/cm², CAT 2 ≥ 8 cal/cm², CAT 3 ≥ 25 cal/cm², and CAT 4 ≥ 40 cal/cm². The number is the garment system's arc rating (ATPV or EBT, whichever is lower). Higher categories — CAT 3 and CAT 4 — usually require layered arc-rated garments rather than a single shirt, and only the tested rating of the system counts.
Can FR clothing be used for an arc-flash hazard if it isn't arc-rated?
No. All arc-rated clothing is flame-resistant, but not all FR clothing is arc-rated. A garment can be genuinely FR — even NFPA 2112 certified for flash fire — and carry no arc rating. For an arc-flash hazard you need an arc rating in cal/cm² that meets your PPE Category minimum, typically referencing ASTM F1506. "FR" alone doesn't qualify for any CAT level.
Why Trust This Guide
This guide is written and reviewed by Wes Calder, an independent flame-resistant-workwear reviewer. Every recommendation is built on the published standards (NFPA 2112, NFPA 70E, ASTM F1506), manufacturer spec sheets and garment tags, hands-on handling, and what tradespeople actually report — and we tell you when a number is a manufacturer claim versus an independent standard, and when a garment is FR but not arc-rated. We earn an affiliate commission if you buy through some of our links, at no extra cost to you, and we never rank by commission over safety — see our affiliate disclosure.
