If you work as an electrician on offshore oil and gas platforms, FPSO vessels, or subsea installations, CompEx certification is effectively mandatory. Virtually every major operator — BP, Shell, TotalEnergies, Equinor, Harbour Energy — requires CompEx as a condition of working on their installations. This guide covers what offshore electricians specifically need to know.

Which CompEx Units Do Offshore Electricians Need?

Most offshore electrical roles require at minimum:

  • Ex01 — Installation in IIA/IIB gas areas (most of the platform)
  • Ex03 — Inspection in IIA/IIB gas areas

For platforms with hydrogen-handling equipment, fuel gas systems, or IIC-designated areas:

  • Ex02 — Installation in IIC areas
  • Ex04 — Inspection in IIC areas

Instrument technicians on offshore installations typically also hold Ex05 — covering intrinsically safe systems, Zener barriers, galvanic isolators, and IS earthing.

What Makes Offshore Ex Work Different?

Offshore Ex work presents challenges not always found onshore:

  • Marine environment — salt spray, humidity, and condensation cause accelerated corrosion of earth tags, armour connections, and enclosure surfaces. Corrosion assessment is a key inspection skill offshore.
  • Vibration — process equipment vibration can loosen cable glands, bolts, and terminal connections over time.
  • Simultaneous operations (SIMOPS) — inspection often occurs while processes are live. Understanding the permit to work system and gas-free certification is essential.
  • Remote locations — replacement parts may not be immediately available, making the correct use of temporary measures and Category X escalation procedures critical.
  • Mixed gas groups — offshore platforms often have both IIB and IIC zones, requiring awareness of which standard applies in each area.
Aberdeen and the North Sea

Aberdeen is the UK's primary hub for North Sea offshore electrical personnel. Most offshore electricians based in Aberdeen hold both Ex01/Ex03 and Ex02/Ex04 due to the prevalence of IIC-rated areas on North Sea platforms. CompEx preparation courses are available in Aberdeen but online preparation platforms like EX Academy allow flexible study during offshore rotations or between hitch periods.

Offshore Inspection — Common Deficiencies

Offshore inspection experience shows certain deficiencies recur more frequently than onshore due to the marine environment:

  • Corroded external earth tags — Category A or B depending on severity
  • Loose or missing bolts on Ex d equipment — Category X for missing, Category A for loose
  • Paint overspray on Ex d flamepaths — Category A if gap maintained, Category X if gap compromised
  • Cable gland seal degradation — Category A or X depending on entry status
  • Missing or damaged Ex e IP gaskets — Category A
  • Moisture ingress — Category X if it has reached live parts

Preparing for Your Offshore CompEx Assessment

Offshore rotations make classroom attendance challenging. EX Academy is designed for exactly this situation — you can work through inspection simulations and practice questions during your hitch period, during transit, or in your own time between offshore rotations. The platform covers all 15 inspection scenarios across Zone 0, 1, 2, and 21 — including marine environment scenarios with corrosion-related deficiencies.