# Intrinsically Safe (IS) — North American vs IEC/ATEX explosion protection designations

For Intrinsically Safe (IS), category is protection concept; iec / atex designation is Ex i (Ex ia, Ex ib); iec standard is IEC 60079-11; basis or note is Limit energy below ignition threshold, recorded from its source on 2026-08-06.

- **Category:** protection concept _(our reading, not quoted from the source)_
- **North American designation:** Intrinsically Safe (IS) _(verified: appears in the quote below)_
- **IEC / ATEX designation:** Ex i (Ex ia, Ex ib) _(verified: appears in the quote below)_
- **IEC standard:** IEC 60079-11 _(verified: appears in the quote below)_
- **Basis or note:** Limit energy below ignition threshold _(verified: appears in the quote below)_

## What the source says

> Intrinsically Safe (IS) | Ex i (Ex ia, Ex ib) | IEC 60079-11 | Limit energy below ignition threshold

## 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/).