# Groups A, B, C, D — North American vs IEC/ATEX explosion protection designations

For Groups A, B, C, D, category is system attribute; iec / atex designation is Groups IIC, IIB, IIA; basis or note is Gas classification, recorded from its source on 2026-08-06.

- **Category:** system attribute _(our reading, not quoted from the source)_
- **North American designation:** Groups A, B, C, D _(verified: appears in the quote below)_
- **IEC / ATEX designation:** Groups IIC, IIB, IIA _(verified: appears in the quote below)_
- **Basis or note:** Gas classification _(verified: appears in the quote below)_

## What the source says

> Gas classification | Groups A, B, C, D | Groups IIC, IIB, IIA | Groups IIC, IIB, IIA

## Source

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

Last verified: 2026-08-06. Review by: 2028-08-05.
Part of [North American vs IEC/ATEX explosion protection designations](https://referencesource.org/ex-classification-system-crosswalk/).