65 records
What is the IEC or ATEX equivalent of this North American hazardous-area rating?
65 records covering 56 north american designations, one fact each. Every value is transcribed from the source that states it and carries the sentence it was taken from: 4 sources across 4 sites, last checked 2026-08-06, due for re-check by 2028-08-05. Every record is listed below, each linking the page its value came from.
4 records where two or more sources state different values. Both sides are reproduced on the record page, each with its own source and quote.
About this data
Crosswalk between the two concurrent hazardous-area classification systems: the North American Class / Division system of NEC Articles 500 and 505 (NFPA 70) and the CSA code, against the Zone system of IEC 60079, ATEX and IECEx. Each record is one designation in one system with its stated counterpart in the other, covering area classification (Division 1 and 2 against Zone 0, 1, 2, 20, 21, 22), gas groups (A, B, C, D against IIA, IIB, IIC, IIB+H2), dust groups (E, F, G against IIIA, IIIB, IIIC), protection concepts (explosion-proof against Ex d, intrinsically safe against Ex i, purged/pressurized against Ex p, dust-ignition-proof against Ex t, non-incendive against Ex nA/Ex ec) with the IEC standard number for each, and temperature codes T1 to T6 with their maximum surface temperatures. Answers 'is ATEX Ex d IIB T4 the same as Class I Div 1 Group C', 'what does T2D mean and is there an IEC equivalent', 'Division 1 or Zone 1 which is stricter', 'NEC Group B IEC equivalent', and 'can I install Zone 1 equipment in a Division 1 area'. Three things the mapping gets wrong when stated as a simple table: NEC 500 has no Zone 0 equivalent so Division 1 spans Zone 0 and Zone 1 and is under-specified for Zone 0; the North American temperature codes T2A, T2B, T2C, T2D, T3A, T3B, T3C and T4A have no IEC counterpart at all; and publishers disagree on NEC Group B, giving it as IIC or as IIB+H2, which changes the required flameproof gap. Every counterpart is quoted from the page that stated it and attributed, so the disagreement is visible.
The data
| North American designation | Category | IEC / ATEX designation | Basis or note | IEC standard | Maximum surface temperature (C) |
|---|---|---|---|---|---|
| 2 levels (Div 1, Div 2) | system attribute | 3 levels (Zone 0, 1, 2) | Risk gradation | ||
| Class III | area classification | Ignitable fibers | |||
| NEC 500 (Class/Division) | system attribute | ATEX / IECEx (Zone) | Geographic use: USA, Canada vs EU, UK, most of the world | ||
| Class II, Group G | dust group | Grain, flour, plastic dusts | |||
| NFPA 70 (adopted by AHJs) | system attribute | EU Directive 2014/34/EU / IECEx scheme | Legal framework | ||
| Explosion-proof (XP) | protection concept | Ex d (Flameproof) | Contain the explosion inside the enclosure | IEC 60079-1 | |
| Flameproof enclosure | protection concept | Ex d | Flameproof enclosure | ||
| Increased safety | protection concept | Ex e | Increased safety | ||
| Intrinsically Safe (IS) | protection concept | Ex i (Ex ia, Ex ib) | Limit energy below ignition threshold | IEC 60079-11 | |
| Intrinsically Safe | protection concept | Ex i | Intrinsic safety | ||
| Encapsulation | protection concept | Ex m | Encapsulation | ||
| Non-incendive | protection concept | Ex nA / Ex ec | Normal operation cannot cause ignition | IEC 60079-15 / -7 | |
| Hermetically sealed | protection concept | Ex nC / Ex m | Seal ignition source from atmosphere | IEC 60079-15 / -18 | |
| Purged/Pressurized | protection concept | Ex p (Ex px, Ex py, Ex pz) | Maintain positive pressure with inert gas | IEC 60079-2 | |
| Pressurization | protection concept | Ex p | Pressurization | ||
| Dust-ignition-proof | protection concept | Ex t (Dust protection by enclosure) | Prevent dust ingress and limit surface temperature | IEC 60079-31 | |
| Group E | gas group | Metal dust | |||
| Group F | gas group | Carbon dust | |||
| Group G | gas group | Grain / flour dust | |||
| Groups A, B, C, D | system attribute | Groups IIC, IIB, IIA | Gas classification | ||
| Explosion-proof (XP), intrinsically safe (IS) | system attribute | IEC-aligned types (Ex d, Ex i, Ex e, etc.) | Protection concept | ||
| Class I, Group D | gas group | IIA | Propane | ||
| Group Dsources differ | gas group | IIA | MESG >0.90 mm | ||
| Class I, Group C | gas group | IIB | Ethylene | ||
| Group Csources differ | gas group | IIB | MESG 0.50–0.90 mm | ||
| Class I, Group B | gas group | IIB + H2 | Hydrogen | ||
| Class I, Group A | gas group | IIC | Acetylene | ||
| Group Asources differ | gas group | IIC | MESG <0.50 mm | ||
| Group B | gas group | IIC | Hydrogen | ||
| Group B | gas group | IIC (partially IIB+H₂) | MESG <0.50 mm | ||
| Class III | dust group | IIIA | Fibers and flyings | ||
| Class II, Group F | dust group | IIIB | Carbon dusts | ||
| Class II, Group E | dust group | IIIC | Metal dusts | ||
| NRTLs (UL, FM, CSA) | system attribute | Notified Bodies (ATEX) / ExCBs (IECEx) | Certification body | ||
| T1 | temperature code | T1 | Ignition temperature of gas / dust >450 | 450 | |
| T2 | temperature code | T2 | Ignition temperature of gas / dust >300-450 | 300 | |
| T3 | temperature code | T3 | Ignition temperature of gas / dust >200-300 | 200 | |
| T4 | temperature code | T4 | Ignition temperature of gas / dust >135-200 | 135 | |
| T5 | temperature code | T5 | Ignition temperature of gas / dust >100-135 | 100 | |
| T6 | temperature code | T6 | Ignition temperature of gas / dust >85-100 | 85 | |
| T2A | temperature code | Ignition temperature of gas / dust >280-300 | 280 | ||
| T2B | temperature code | Ignition temperature of gas / dust >260-280 | 260 | ||
| T2C | temperature code | Ignition temperature of gas / dust >230-260 | 230 | ||
| T2D | temperature code | Ignition temperature of gas / dust >215-230 | 215 | ||
| T3A | temperature code | Ignition temperature of gas / dust >180-200 | 180 | ||
| T3B | temperature code | Ignition temperature of gas / dust >165-180 | 165 | ||
| T3C | temperature code | Ignition temperature of gas / dust >160-165 | 160 | ||
| T4A | temperature code | Ignition temperature of gas / dust >120-135 | 120 | ||
| Class I | area classification | Zone 0, 1, 2 (gas) | Flammable gases and vapors | ||
| Class I (gas), II (dust), III (fibers) | system attribute | Zone 0, 1, 2 (gas); Zone 20, 21, 22 (dust) | Hazard basis | ||
| Class I Division 1 | area classification | Zone 0 | Continuous hazard | ||
| (no NEC 500 equivalent) | area classification | Zone 0 | Explosive atmosphere continuously or for long periods (>1000 hrs/yr) | ||
| (no NEC equivalent) | area classification | Zone 0 | Explosive atmosphere present continuously or for long periods | ||
| Division 1 | area classification | Zone 0 / Zone 1 | Hazard present during normal operation | ||
| Class I Division 1 | area classification | Zone 1 | Frequent hazard | ||
| (no NEC equivalent) | area classification | Zone 1 | Explosive atmosphere likely during normal operation | ||
| Division 1 | area classification | Zone 1 (+ Zone 0) | Explosive atmosphere likely during normal operation (10–1000 hrs/yr) | ||
| Class I Division 2 | area classification | Zone 2 | Occasional hazard | ||
| Division 2sources differ | area classification | Zone 2 | Explosive atmosphere not likely; only abnormal conditions (<10 hrs/yr) | ||
| (no NEC equivalent) | area classification | Zone 2 | Explosive atmosphere unlikely in normal operation, only short duration eg. accidental leakage | ||
| Class II | area classification | Zone 20, 21, 22 (dust) | Combustible dust | ||
| Class II Groups E, F, G | system attribute | Zone 20, 21, 22 (IIIA, IIIB, IIIC) | Dust classification | ||
| (no NEC equivalent) | area classification | Zone 20 | Combustible dust present continuously | ||
| (no NEC equivalent) | area classification | Zone 21 | Dust likely during normal operation | ||
| (no NEC equivalent) | area classification | Zone 22 | Dust unlikely except briefly |
Where this came from
Every record above links the page it was taken from and quotes the sentence that states it. These are the 4 sources this dataset was assembled from.
- exknowledge.comhttps://exknowledge.com/pages/nec-500-vs-atex-iec.html
- inframena.comhttps://www.inframena.com/hazardous-area-classification-equivalency-guide/
- e2s.comhttps://www.e2s.com/guide-for-hazardous-areas/gas-and-dust-groups
- ldpi-inc.comhttps://ldpi-inc.com/resources/classification-codes/class-1-locations/
Machine-readable
- data.jsonThe whole dataset — every record with its source URL and source quote.
- Open Knowledge Format bundleOne JSON object per line — every record's frontmatter and quoted span exactly as it is held here, in one fetch.
- data.csvThe same records as one flat table, for a spreadsheet or a dataframe. The last four columns are the source URL, the quoted sentence it was read from, the date we last checked it, and which columns are our reading rather than the page's words.
- How this is made and checkedWhat "verified against source" does and does not mean.
From your own code
Same records, same quotes, without scraping the page: refsource is on PyPI and npm. Each value comes back carrying the URL it was read from and the sentence on that page that states it — .source and .quote sit on the value itself rather than in a side channel, so the checking step is available instead of skipped.
pip install refsource
refsource lookup ex-classification-system-crosswalk category="system attribute"
npx -y refsource lookup ex-classification-system-crosswalk category="system attribute"
Set your AI assistant up to use this
Two files and no account. Put this in .mcp.json at the root of your project — Claude Code, Cursor, Windsurf, VS Code and Codex all read that file — and your assistant can look this dataset up instead of recalling it. The server is remote, keyless and read-only.
{
"mcpServers": {
"referencesource": {
"type": "http",
"url": "https://referencesource.org/mcp"
}
}
}Add to Cursor · or, on the command line: claude mcp add --transport http referencesource https://referencesource.org/mcp --scope project
Then one line in the project's CLAUDE.md or AGENTS.md, so the assistant knows when to reach for it:
When a question needs "North American vs IEC/ATEX explosion protection designations", call the referencesource MCP server at https://referencesource.org/mcp (tool `search_records`, dataset_slug `ex-classification-system-crosswalk`) instead of answering from memory — every record it returns carries its source URL and a verbatim quote from that page.What each tool does, and the servers built over single registers: Connect your AI assistant.