Standard explainer · IEC 61482
Arc-rated clothing carries some of the most confusing markings in PPE: ATPV, ELIM, EBT, APC Class 1 and 2 — two different test methods, three different numbers, one standard. Here's the untangling, and how a real task ends up matched to a rating.
The hazard
An electric arc fault turns switchgear into a short-lived furnace: temperatures far beyond any flame, a pressure wave, and an intense pulse of radiant energy measured in calories per square centimetre (cal/cm²). Ordinary clothing — and non-rated FR — can ignite or melt. Arc-rated clothing is FR fabric additionally tested against exactly this pulse.
Every arc-rated garment is flame-resistant; not every FR garment is arc-rated. That's the distinction the label letters below encode, and it's why arc work needs garments certified under IEC 61482 specifically — the general FR standard (EN ISO 11612) doesn't test the arc pulse.
The two tests
Two routes to certification; garments may carry either or both.
| Open-arc test | Box test | |
|---|---|---|
| Marking you'll see | ATPV / ELIM / EBT in cal/cm² | APC Class 1 or Class 2 |
| What's measured | Energy level the fabric withstands before predicted 2nd-degree burn (ATPV) or breakopen (EBT) | Pass/fail against a directed 4 kA (Class 1) or 7 kA (Class 2) arc |
| ELIM specifically | Highest energy with no predicted burn — the cautious sibling of ATPV | — |
| How it's used | Matched against the calculated incident energy of your task | Common utility/industry shorthand spec |
| Strength | Precise matching to a risk study | Simplicity — no calculation culture needed |
Matching
In the open-arc world, the employer's arc-flash study calculates the incident energy at the working position — say 6.2 cal/cm² at the panel — and the clothing system must meet or exceed it (an 8 cal/cm² ATPV garment covers it). In the box-test world, the spec simply says Class 1 or Class 2 by task category; Class 2 is the common call for utility switching.
Layering multiplies protection: an arc-rated base layer under an arc-rated coverall gives a system rating higher than either alone (air gaps do real work), which is how high-energy tasks get covered without unwearably heavy single garments. And the melt-layer rule holds with extra force — synthetics anywhere in the stack are the failure mode. The wearer-side kit list lives in PPE for electricians.
Questions
Both come from the open-arc test, in cal/cm². ATPV is the energy at which there's a 50% probability of a second-degree burn through the fabric; ELIM is the highest energy with no predicted burn at all. ELIM is the more conservative figure — where both appear, ELIM will be the lower number.
The garment passed the IEC 61482 box test against a directed 7 kA arc (Class 1 is 4 kA). It's the common specification for utility switching and LV industrial work where employers spec by class rather than running incident-energy calculations.
No. All arc-rated clothing is flame-resistant, but general FR (EN ISO 11612) hasn't been tested against an arc's energy pulse. If the risk assessment says arc, the label must say IEC 61482 — with an ATPV/ELIM value or an APC class.
Yes — and it's standard practice. An arc-rated base layer under an arc-rated outer produces a system rating higher than either garment alone, thanks to the insulating air gap. Every layer in the stack must be arc-rated or natural fibre; one synthetic layer breaks the system.
Multi-norm coveralls, arc-rated kit and FR base layers from stock — with badging that doesn't void the certification.