How to Read an ATEX Nameplate

The Typical ATEX Nameplate

An ATEX-certified product will have a nameplate showing:

CE 0123
 ⚠  II 2 G Ex d IIC T4 Gb
Certificate: ExCB-12.0034X
Ta: -20°C to +60°C

Every letter and number means something. This page decodes each element. See also the Ex markings reference for the complete list.

Reading Order: Left to Right

Start with the regulatory marks, then move to the technical details:

1. CE marking + Notified Body number — EU market access proof
2. ⚠ (ATEX symbol) — Hexagon with "Ex" inside
3. Equipment Group and Category — Roman numeral + digit + letter (II 2 G)
4. Ex marking — Protection method, gas group, temperature class, EPL
5. Certificate number — Traceability to the Type Examination Certificate
6. Special conditions — X suffix or noted separately
7. Ambient temperature range — Ta limits

CE Marking + Notified Body Number

CE 0123

CE — Conformité Européenne (European Conformity). This mark indicates the product meets EU safety, health, and environmental requirements. For ATEX equipment, it means the manufacturer declares compliance with Directive 2014/34/EU.

0123 — Four-digit Notified Body identification number. This organization performed the EU Type Examination and issued the certificate. Examples:

• 0102 — ZELM (Germany)
• 0344 — CSA (Canada, EU operations)
• 0832 — SIRA (UK, now operates under UKCA)
• 2460 — DNV (Norway)

You can look up Notified Bodies on the EU Commission's NANDO database.

Note: The Notified Body number only appears on Category 1, M1, and M2 equipment. Category 2 and 3 equipment may show only CE without a number, because the manufacturer self-certifies under Module A (internal production control).

ATEX Symbol (⚠)

 ⚠ 

The hexagon with "Ex" inside is the mandatory ATEX marking symbol. It indicates the equipment is designed for explosive atmospheres per Directive 2014/34/EU.

Not to be confused with:

• A triangle warning symbol (general hazard)
• The IECEx Ex symbol (same hexagon, but labeled differently on nameplate)

Both ATEX and IECEx use the hexagon, so you'll often see it on dual-certified equipment.

Equipment Group and Category

II 2 G

Equipment Group (I or II)

• Group I — Mining equipment (underground coal mines, endangered by methane/firedamp)
• Group II — Surface industries (oil & gas, chemical, pharmaceutical, etc.)

Most industrial equipment is Group II.

Category (1, 2, or 3)

Indicates the level of protection and suitable zones:

Atmosphere Type (G or D)

• G — Gas, vapor, or mist
• D — Dust (combustible dust clouds or layers)

Examples

• II 1 G — Group II, Category 1, for gas (Zone 0 suitable, EPL Ga)
• II 2 D — Group II, Category 2, for dust (Zone 21 suitable)
• II 2 GD — Suitable for both gas (Zone 1) and dust (Zone 21)
• II 3 G — Group II, Category 3, for gas (Zone 2 only)

Ex Marking (The Technical Part)

Ex d IIC T4 Gb

This is where the engineering details live. Break it into five parts:

1. Ex

Short for "Explosive atmospheres." Always present on Ex equipment.

2. Protection Method (d)

The type of protection concept used. Common methods:

Combinations are common: Ex de means the equipment uses both flameproof (d) and increased safety (e) methods—often a flameproof motor chamber with increased safety terminal box.

3. Gas Group (IIA, IIB, IIC)

Indicates which gases the equipment is certified for, based on ignition sensitivity (see gas groups for details):

Hierarchy rule: IIC equipment can be used in IIB or IIA atmospheres. IIB can be used in IIA. But IIA equipment cannot be used in IIB or IIC atmospheres.

For dust: Groups IIIA (combustible flyings), IIIB (non-conductive dust), IIIC (conductive dust) are used. Often shown simply as "III" for all dust types.

4. Temperature Class (T1–T6)

Maximum surface temperature the equipment will reach, even under fault conditions:

Alternative notation: Sometimes you'll see a specific temperature instead of a T-class, like T95°C. This means the maximum surface temperature is exactly 95°C.

For dust: Temperature markings show the maximum surface temperature directly (e.g., T 135°C or T95°C) rather than using T-classes, because dust ignition temperatures vary widely and layer ignition must be considered.

5. Equipment Protection Level (Ga, Gb, Gc, Da, Db, Dc)

Introduced in IEC 60079-0:2011 (and ATEX 2014/34/EU). Indicates the number of faults the equipment can tolerate:

Correlation to Category:

• Category 1 → EPL Ga / Da
• Category 2 → EPL Gb / Db
• Category 3 → EPL Gc / Dc

EPL is more precise because it accounts for protection method details (e.g., Ex ia = Ga, Ex ib = Gb).

Complete Marking Examples

Example 1: Flameproof Motor

CE 0344
 ⚠  II 2 G Ex d IIC T4 Gb

Translation:

• CE 0344 — Certified by Notified Body 0344 (CSA Group)
• II — Group II (surface industries)
• 2 G — Category 2, gas (suitable for Zone 1)
• Ex d — Flameproof enclosure
• IIC — Suitable for all gas groups including hydrogen
• T4 — Maximum surface temperature 135°C
• Gb — EPL Gb (Zone 1 protection level)

Use case: Can be installed in Zone 1 or Zone 2 with any gas having an auto-ignition temperature above 135°C (propane, methane, hydrogen, ethylene, etc.).

Example 2: Intrinsically Safe Transmitter

CE
 ⚠  II 1 G Ex ia IIC T4 Ga

Translation:

• CE (no number) — Category 1 equipment, but some manufacturers self-certify intrinsic safety under Module B+D
• II 1 G — Category 1, gas (suitable for Zone 0)
• Ex ia — Intrinsic safety, 2-fault tolerance
• IIC — All gas groups
• T4 — Max surface temp 135°C
• Ga — EPL Ga (Zone 0 suitable)

Use case: Can be installed in Zone 0, 1, or 2. Requires associated apparatus (safety barrier or isolator) to limit circuit energy. Check entity parameters (Ui, Ii, Ci, Li) against the barrier and cable.

Example 3: Increased Safety Terminal Box

CE 0102
 ⚠  II 2 G Ex eb IIC T6 Gb

Translation:

• CE 0102 — Certified by ZELM
• II 2 G — Category 2, gas (Zone 1)
• Ex eb — Increased safety terminal box (no arcing/sparking parts)
• IIC — All gas groups
• T6 — Max surface temp 85°C
• Gb — EPL Gb

Use case: Suitable for Zone 1/2. No hot work required—terminals are designed not to spark under normal operation. Often used for marshalling intrinsically safe circuits or general wiring.

Example 4: Pressurized Control Panel

CE 2460
 ⚠  II 2 G Ex px IIB T4 Gb

Translation:

• CE 2460 — Certified by DNV
• II 2 G — Category 2, gas
• Ex px — Type 'x' pressurization (suitable for Zone 1)
• IIB — Suitable for Gas Groups IIA and IIB (not IIC)
• T4 — Max surface temp 135°C
• Gb — EPL Gb

Use case: Control panel in Zone 1 containing standard industrial components (relays, PLCs, etc.). Requires pressurization system maintaining positive pressure with inert gas or clean air. Interlocks shut down equipment if pressure is lost.

Example 5: Dust Ignition Proof Equipment

CE 0344
 ⚠  II 2 D Ex tb IIIC T135°C Db IP66

Translation:

• II 2 D — Category 2, dust (Zone 21)
• Ex tb — Dust-tight enclosure with temperature limitation
• IIIC — Conductive dust (metal dusts, carbon black)
• T135°C — Maximum surface temperature 135°C
• Db — EPL Db (Zone 21)
• IP66 — Dust-tight and protected against powerful water jets

Use case: Suitable for Zone 21/22 environments with conductive dust. Common in grain handling, metal powder processing, or pharmaceutical manufacturing.

Example 6: Combined Gas and Dust

CE 0832
 ⚠  II 2 GD Ex d IIB T4 Gb / Ex tb IIIC T135°C Db

Translation: Dual-certified for both gas and dust:

• For gas: Ex d IIB T4 Gb (flameproof, Gas Group IIB, Zone 1)
• For dust: Ex tb IIIC T135°C Db (dust-tight, conductive dust, Zone 21)

Use case: Flexible installation in facilities with both gas and dust hazards (e.g., chemical plants processing solids and liquids).

Certificate Number

Certificate: SIRA 12.0045X

Formats vary by Notified Body, but typically include:

• SIRA — Notified Body abbreviation
• 12 — Year of certification (2012)
• 0045 — Sequential certificate number
• X — Special conditions apply (see below)

The certificate number links the nameplate to the full EU Type Examination Certificate, which contains detailed specifications, test results, and installation requirements.

Special Conditions (X Suffix)

If the certificate number ends in X, special conditions apply. These are documented in the EU Type Examination Certificate and must be followed during installation, operation, or maintenance. Examples:

• "Cable entries must use certified Ex d cable glands with metric M20 threads."
• "Maximum number of starts per hour: 10." (for motors)
• "Ambient temperature range: -20°C to +40°C."
• "Flameproof joints must be inspected annually and greased with XYZ compound."
• "Do not use in atmospheres containing halogenated solvents."

Ignoring special conditions can void certification and create safety risks. Always obtain and read the full certificate.

Ambient Temperature Range

Ta: -20°C to +60°C

Ta = ambient temperature. This defines the environmental temperature limits for safe operation. Common ranges:

• -20°C to +40°C — Standard industrial (IEC 60079-0 default)
• -40°C to +60°C — Extended range for outdoor installations or hot climates
• -60°C to +40°C — Arctic conditions (rare, requires special materials)

Why it matters: Temperature class (T4, etc.) is calculated at maximum ambient temperature. If you operate equipment outside its Ta range, the surface temperature may exceed the certified limit, creating an ignition risk.

Other Common Nameplate Information

Electrical Ratings

230 V AC, 50 Hz, 3.2 A

Standard electrical parameters. Must match or stay within the certified range.

IP Rating

IP66

Ingress Protection rating (IEC 60529):

• First digit (6) — Dust-tight
• Second digit (6) — Protected against powerful water jets

Higher IP ratings are common in Ex equipment to maintain enclosure integrity. Ex d often requires IP54 minimum; Ex tb (dust ignition protection) requires IP6X.

Entity Parameters (Intrinsic Safety)

Ui = 30 V, Ii = 200 mA, Ci = 50 nF, Li = 100 µH

For intrinsically safe equipment:

• Ui — Maximum input voltage
• Ii — Maximum input current
• Ci — Internal capacitance
• Li — Internal inductance

These must be compared against the associated apparatus (barrier/isolator) parameters (Uo, Io, Co, Lo) to ensure system safety.

Quick Reference Checklist

When reading an ATEX nameplate, verify:

1. ☐ Zone suitability — Category/EPL matches your classified area (Zone 0/1/2)
2. ☐ Gas group — IIA/IIB/IIC covers your process gases
3. ☐ Temperature class — T-class is below your gas's auto-ignition temperature
4. ☐ Ambient temperature — Site Ta is within equipment's Ta range
5. ☐ Special conditions — Check for X suffix and obtain certificate
6. ☐ Electrical ratings — Voltage, current, frequency match supply
7. ☐ Protection method — Suitable for application (Ex d for motors, Ex ia for sensors, etc.)

Common Mistakes to Avoid

Using IIB equipment in an IIC atmosphere

Gas group hierarchy is strict: IIC equipment works everywhere, but IIB does not work in IIC. If your area has hydrogen or acetylene, you need IIC-rated equipment.

Ignoring the X suffix

Special conditions are not optional. They're part of the certification. If you ignore them (e.g., using the wrong cable gland), the equipment is no longer certified.

Exceeding ambient temperature limits

If you install equipment rated Ta: -20°C to +40°C in a location that reaches 55°C, the surface temperature will exceed the certified T-class. This creates an ignition risk.

Confusing Category with Zone

Category 2 is suitable for Zone 1, but it's not the same as Zone 1. The zone is a classification of the location. The category is a rating of the equipment. Match them correctly: Category 1 → Zone 0, Category 2 → Zone 1, Category 3 → Zone 2.

Assuming all Ex d is the same

Ex d IIA is different from Ex d IIC. The flameproof gap dimensions are different. Always check the gas group.

Related Topics

• Reading Ex Markings — General guide to all Ex marking types (IECEx, NEC, etc.)
• Equipment Protection Levels — Understanding Ga/Gb/Gc and how they map to zones
• Gas Groups — IIA, IIB, IIC explained with MESG and MIC details
• Temperature Classes — T1–T6 explained with auto-ignition temperature tables
• Protection Methods — All Ex types (d, ia, e, px, m, etc.) in detail