Selecting and installing explosion-proof equipment for hazardous locations requires systematically verifying a series of parameters that are each individually necessary — no single parameter can substitute for another. This checklist covers equipment selection, installation compliance, and documentation requirements for Class I Division 1, Class I Division 2, ATEX Zone 1, and ATEX Zone 2 installations of cameras, lighting, and associated electrical equipment.
Pre-Selection Checklist: Information Required Before Specifying Equipment
- Area classification drawing obtained — current revision confirming Class/Division/Group/T-code (NEC) or Zone/Category/Gas Group/T-class (ATEX/IECEx) for the specific installation location
- All flammable substances identified — including primary process materials and secondary materials (cleaning solvents, seal fluids, purge gases) present in the area
- Gas group confirmed for most restrictive substance — if H2S is present, Group C (NEC) or IIB (ATEX) is required regardless of primary process group
- Auto-ignition temperatures verified — T-code requirement confirmed against AIT of most restrictive substance (NFPA 497 Table B.1 or IEC 60079-20-1)
- Applicable certification standard confirmed — UL for U.S./Canada, ATEX for EU, IECEx for international, UKEX for post-Brexit UK
- Environmental requirements documented — ambient temperature range, IP rating requirement, salt spray/corrosive atmosphere, vibration level
- Conduit entry configuration identified — conduit size, entry quantity, threading standard (NPT for NEC or Metric for ATEX/IECEx)
Equipment Selection Verification Checklist
- Certification standard matches jurisdiction — UL 844/UL 1203 for U.S., CSA for Canada, ATEX CE mark for EU, UKEX for UK, IECEx for international
- Class and Division match — Class I Div 1 equipment for Class I Div 1 area; Class I Div 2 equipment is NOT acceptable in Div 1 areas
- Gas Group certified covers all substances present — Group C or B if H2S present; Group B if hydrogen present; IIB minimum for H2S in ATEX
- T-code is below AIT of most restrictive substance — verify for every substance present, not just primary process material
- IP rating meets environmental requirements — IP65 minimum for most industrial indoor; IP66 for outdoor or washdown; IP67 for marine or immersion risk
- Temperature range covers installation ambient — particularly important for outdoor installations in cold or hot climates
- Certification verified in authoritative database — not just from product markings or datasheet; verified in UL Product iQ, Notified Body records, or iecex.iec.ch
- Exact model number and configuration confirmed in listing — suffix variations (lens type, mounting, conduit entry size) verified as covered under the certificate
Installation Compliance Checklist (NEC Article 501)
- Wiring method is threaded RMC or threaded IMC (Division 1) — EMT and non-threaded conduit not permitted in Class I Division 1
- All conduit fittings are listed explosion-proof fittings — standard commercial fittings not permitted
- Conduit entries engage minimum five full threads — verify engagement at every explosion-proof enclosure before sealing
- EYS sealing fittings installed within 18 inches of every explosion-proof enclosure (Division 1)
- Sealing fittings installed at classified/unclassified boundaries — both entering and leaving classified area
- Sealing compound is approved type — manufacturer-listed sealing compound; not packing yarn or unapproved material
- Physical guards installed where required — fixtures in locations subject to physical damage protected by guards or positioning
- No unauthorized modifications to any certified equipment — no drilled holes, no substituted lenses, no unapproved lamp types
Documentation Checklist
- Current area classification drawing on file — signed and dated by qualified engineer
- Equipment schedule completed — every installed item listed with certified model number, certificate/listing number, Class/Division/Group/T-code, and location
- Installation records filed — conduit routing, seal locations, as-built markups
- Contractor qualifications documented — installer experienced with NEC Article 500-504 installations
- Initial inspection completed and signed — pre-energization inspection per IEC 60079-17 or equivalent
- Ongoing inspection schedule established — visual inspection every 1-3 years; close inspection every 3-6 years per IEC 60079-17
See: Explosion-Proof Camera Maintenance and Compliance Checklist | How to Design a Hazardous Area CCTV System | Hazardous Area Classification Glossary
Frequently Asked Questions
What information is needed to select explosion-proof equipment?
Six pieces of information from the area classification drawing and process documentation: Class/Division (or Zone), Gas/Dust Group, T-code requirement, applicable certification standard (UL/ATEX/IECEx), environmental requirements (IP rating, temperature, corrosion), and physical installation requirements (conduit entry type, mounting configuration).
What is the most common mistake in explosion-proof equipment selection?
Selecting the correct Class and Division but the wrong Group — particularly specifying Group D equipment in areas with H2S service requiring Group C, or Group C in hydrogen areas requiring Group B. This error occurs when the specification is based on the primary process fluid rather than all substances present in the area.
When does an explosion-proof installation require re-verification?
When a process change introduces a substance with a different gas group or lower auto-ignition temperature than the existing equipment covers; when area classification changes from Division 2 to Division 1; when equipment is field-modified; or when a PHA/HAZOP reveals a classification error. Process changes that introduce new flammable substances require review of all equipment in the affected area before restart.
Does explosion-proof equipment need to be re-tested after installation?
The equipment certification itself does not require re-testing after installation. However, the installation must be inspected to verify correct installation: conduit entries properly threaded (five full threads), seals installed within required distances, no unauthorized modifications, and physical guards in place where required. This inspection is documented before returning the area to service.
Browse certified explosion-proof products: Explosion-Proof Camera Systems | Explosion-Proof LED Lighting
Related compliance guides: Class 1 Division 1 vs Division 2 | ATEX Zone Selection Guide | NEC vs ATEX Crosswalk | Maintenance Compliance Checklist
Need certified equipment with full documentation? Request an Industrial Quote — Veilux provides ATEX, IECEx, UL, and cUL certification packages for engineering submittals and AHJ review.