What Is an Ex-Proof Luminaire? Types and Selection Criteria
An ex-proof luminaire is a light fitting designed and certified not to become an ignition source in explosive atmospheres containing flammable gas, vapour or dust.
An ex-proof luminaire is a light fitting designed and certified not to become an ignition source in explosive atmospheres where flammable gas, vapour or dust may be present. It is used in classified hazardous areas such as fuel and LPG facilities, paint and solvent stores, chemical plants, flour mills and silos. An IP65 tri-proof luminaire is no substitute: the IP code only covers dust and water ingress.
Types by zone
| Zone (gas / dust) | Explosive atmosphere | Required equipment category |
|---|---|---|
| Zone 0 / 20 | Present continuously or for long periods | Category 1 (EPL Ga / Da) |
| Zone 1 / 21 | Likely occasionally in normal operation | Category 2 (EPL Gb / Db) or 1 |
| Zone 2 / 22 | Not expected in normal operation, short-lived if it occurs | Category 3 (EPL Gc / Dc), 2 or 1 |
A higher category can be used in a lower zone, not the other way round. The protection type (e.g. Ex d flameproof, Ex e increased safety, Ex t dust enclosure) is in the Ex marking; reading the label is explained in the Ex-Proof Junction and Push Button Box guide.
Selection criteria
- Zone and category: The category must match the zone map in the site's explosion protection document.
- Gas or dust group: The group (gas IIA, IIB, IIC; dust IIIA, IIIB, IIIC) must equal or exceed that of the substance present.
- Temperature class: The maximum surface temperature must stay below the substance's ignition temperature: T1 450 °C, T2 300 °C, T3 200 °C, T4 135 °C, T5 100 °C, T6 85 °C.
- Ambient temperature: Unless the label says otherwise, the certificate covers -20…+40 °C; under hot roofs, check the label's Ta.
- Cable entry: The cable must enter through an Ex-certified gland suited to the luminaire's protection type.
Common mistakes
- Taking a tri-proof luminaire for ex-proof: IP65 protects against water and dust, not ignition.
- Installing a Zone 2 luminaire in Zone 1: Zone 1 needs category 2 (EPL Gb) or 1.
- Using uncertified glands or plugs: Close unused entries with Ex-certified blanking plugs.
- Modifying the housing: Drilling holes or fitting a driver the manufacturer did not specify voids the certificate.
Regulations and standards
- 2014/34/EU (ATEX): Applied in Türkiye through the Regulation on Equipment and Protective Systems Intended for Use in Potentially Explosive Atmospheres. Zone classification and the explosion protection document are the employer's duty under the Regulation on the Protection of Workers from the Risks of Explosive Atmospheres.
- IEC/EN 60079 series: 60079-0 general requirements, 60079-10-1 and 60079-10-2 area classification, 60079-14 installations.
Ex-proof luminaires in the Welibaba catalogue
All 4 active products in the Ex-Proof Luminaires category are MAS LED luminaires: MAS-1939EX (20 W), MAS-1828EX (40 W), MAS-1900EX (60 W) and MAS-1902EX (80 W). Per the product pages they are IP65 with ABS/PC housings, and the only zone stated is Zone 2 (manufacturer's catalogue declaration). Do not assume they suit Zone 1 or dust zones: ask the manufacturer for the full Ex marking and certificate number before ordering.
For damp, dusty non-hazardous areas see LED Tri-Proof Luminaires; for hazardous-area junctions and push buttons see ATEX Ex-Proof Junction and Push Button Boxes.
Frequently asked questions
What is the difference between an ex-proof and a tri-proof luminaire?
A tri-proof luminaire is protected against dust and water and carries an IP rating such as IP65. An ex-proof luminaire is certified not to ignite an explosive atmosphere and carries an Ex marking.
Can a Zone 2 luminaire be used in Zone 1?
No. Zone 1 needs a category 2 (EPL Gb) or category 1 luminaire; category 2 can also be used in Zone 2.
Can the MAS ex-proof luminaires be used in dusty atmospheres?
The product pages state only Zone 2, nothing on dust zones. For dust, the marking must include the dust letter D (e.g. II 3D, EPL Dc) and group III (IIIA, IIIB or IIIC); confirm this with the manufacturer.