IP, NEMA and Ex Rating Cheat Sheet
Enclosure and hazardous area ratings on one page: the IP code chart, NEMA types with IP equivalents, zones and EPL, gas and dust groups, temperature classes and Ex protection types.
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A one page A4 sheet to print, pin up in the workshop or keep on your phone. Everything on it is also shown below.
Download PDF A4 · 82 KBIP code: first digit (solids)
| Digit | Protection |
|---|---|
| 0 | None |
| 1 | Objects over 50 mm |
| 2 | Objects over 12.5 mm (fingers) |
| 3 | Objects over 2.5 mm |
| 4 | Objects over 1 mm |
| 5 | Dust protected |
| 6 | Dust tight |
IP code: second digit (water)
| Digit | Protection |
|---|---|
| 0 | None |
| 1 | Vertically dripping water |
| 2 | Dripping water, tilted 15° |
| 3 | Spraying water up to 60° |
| 4 | Splashing from any direction |
| 5 | Water jets (6.3 mm nozzle) |
| 6 | Powerful jets (12.5 mm nozzle) |
| 7 | Immersion to 1 m, 30 min |
| 8 | Continuous immersion beyond 1 m (as specified) |
| 9 | High pressure, high temperature jets |
IEC 60529. IP68 conditions are set by the manufacturer.
NEMA types and nearest IP
| NEMA | Use | IP |
|---|---|---|
| 1 | Indoor | IP10 |
| 2 | Indoor | IP11 |
| 3 | Indoor or outdoor | IP54 |
| 3R | Indoor or outdoor | IP14 |
| 3S | Indoor or outdoor | IP54 |
| 4 | Indoor or outdoor | IP66 |
| 4X | Indoor or outdoor | IP66 |
| 5 | Indoor | IP52 |
| 6 | Indoor or outdoor | IP67 |
| 6P | Indoor or outdoor | IP68 |
| 12 | Indoor | IP52 |
| 12K | Indoor | IP52 |
| 13 | Indoor | IP54 |
NEMA to IP is one way only: a NEMA type meets at least that IP, not the reverse.
Zones and EPL (IEC 60079-10)
| Zone | Hazard present | EPL |
|---|---|---|
| 0 / 20 | Continuously or for long periods | Ga / Da |
| 1 / 21 | Likely in normal operation | Gb / Db |
| 2 / 22 | Not likely, short periods only | Gc / Dc |
Zones 0, 1, 2 for gas; 20, 21, 22 for dust.
Gas and dust groups
| Group | Example |
|---|---|
| IIA | Propane |
| IIB | Ethylene |
| IIC | Hydrogen, acetylene |
| IIIA | Combustible flyings |
| IIIB | Non conductive dust |
| IIIC | Conductive dust |
IIC equipment may be used in IIB and IIA areas.
Temperature classes
| Class | Max surface °C |
|---|---|
| T1 | 450 |
| T2 | 300 |
| T3 | 200 |
| T4 | 135 |
| T5 | 100 |
| T6 | 85 |
Ex protection concepts
| Code | Concept | Zones |
|---|---|---|
| ia | Intrinsic safety | 0, 1, 2 |
| ib | Intrinsic safety | 1, 2 |
| d (db) | Flameproof enclosure | 1, 2 |
| e (eb) | Increased safety | 1, 2 |
| p | Pressurised | 1, 2 |
| m | Encapsulation | 0 to 2 (ma) |
| ec / nA | Non sparking | 2 |
| t | Dust protection by enclosure | 21, 22 |
Example marking
| Gas | Ex db IIC T4 Gb |
| Reading | Flameproof, hydrogen group, max 135 °C, Zone 1 |
| ATEX | ⟨Ex⟩ II 2 G = group II surface, category 2 (Zone 1), gas |
Related Calculators and Tools
Frequently Asked Questions
What does IP67 mean?
Dust tight (6) and protected against temporary immersion to 1 m for 30 minutes (7).
What is the IP equivalent of NEMA 4X?
At least IP66, plus corrosion resistance which IP does not cover.
What does T4 mean on Ex equipment?
The maximum surface temperature is 135 °C, so it is safe for gases with an ignition temperature above 135 °C.
Learn more on the blog
Hazardous area classification: zone 0, zone 1, zone 2
A practical guide on instrumentationblog.in that explains the theory behind this cheat sheet.
Read Full Article