# Class III · dust group — North American vs IEC/ATEX explosion protection designations

For Class III, category is dust group; basis or note is IEC considers fibers within the dust framework, recorded from its source on 2026-10-06.

- **Category:** dust group _(our reading, not quoted from the source)_
- **North American designation:** Class III _(verified: appears in the quote below)_
- **Basis or note:** IEC considers fibers within the dust framework _(verified: appears in the quote below)_

## What the source says

> Fiber hazards: NEC Class III (fibers/flyings) has no IEC equivalent. IEC considers fibers within the dust framework.

## Related records

- [Class II, Group E · dust group · IIIC](https://referencesource.org/ex-classification-system-crosswalk/iiic-dust-group-class-ii-group-e/)
- [Class II, Group F · dust group · IIIB](https://referencesource.org/ex-classification-system-crosswalk/iiib-dust-group-class-ii-group-f/)
- [Class II, Group G · dust group](https://referencesource.org/ex-classification-system-crosswalk/dust-group-class-ii-group-g/)
- [Class III · dust group · IIIA](https://referencesource.org/ex-classification-system-crosswalk/iiia-dust-group-class-iii/)
- [Group E · dust group](https://referencesource.org/ex-classification-system-crosswalk/dust-group-group-e/)
- [Group F · dust group](https://referencesource.org/ex-classification-system-crosswalk/dust-group-group-f/)
- [Group G · dust group](https://referencesource.org/ex-classification-system-crosswalk/dust-group-group-g/)

## Source

- https://exknowledge.com/pages/nec-500-vs-atex-iec.html

Last verified: 2026-10-06. Review by: 2028-10-05.
Part of [North American vs IEC/ATEX explosion protection designations](https://referencesource.org/ex-classification-system-crosswalk/).