Ex Equipment Inspection — Complete IEC 60079-17 Guide
IEC 60079-17 is the international standard governing the inspection and maintenance of Ex electrical equipment. For CompEx Ex03 and Ex04, this standard is the primary reference — every inspection decision you make should be grounded in its requirements.
Why Inspection Matters
Ex equipment is designed to maintain protection even when an internal fault occurs — but this protection can be compromised by physical damage, corrosion, incorrect reassembly, or degradation over time. Periodic inspection detects problems before they create a genuine explosion risk.
The Three Inspection Grades
Visual Inspection
Conducted without opening or disturbing equipment. Checks visible from outside: physical damage, missing warning labels, paint on flamepaths, obvious corrosion, blocked ventilation, damaged cable sheath. Can often be performed during normal plant operation without isolation.
Close Inspection
Includes all visual checks plus checks requiring equipment to be opened or accessed — cable gland thread engagement, terminal condition, flamepath surface condition, internal cleanliness. Typically requires isolation and permit to work.
Detailed Inspection
The most thorough grade — includes all close checks plus measurement with instruments. Flamepath gap measurement with feeler gauges, winding resistance testing, interlock verification, full internal examination. Typically carried out every 3–5 years.
Deficiency Classification
| Category | Action | Examples |
|---|---|---|
| X | Out of service immediately | Missing bolts Ex d, open cable entry, flamepath gap exceeded |
| A | Rectify at next maintenance | Paint on flamepath (gap maintained), loose gland locknut |
| B | Monitor — rectify within agreed period | Surface corrosion on enclosure, minor label damage |
| C | Record only | Minor cosmetic damage, slight discolouration |
A Category X deficiency means the fundamental protection of the equipment is compromised. The equipment must be taken out of service immediately and not returned until the deficiency has been rectified and the equipment re-inspected. There is no discretion on this — it is a black-and-white requirement of IEC 60079-17.
Inspection Documentation
IEC 60079-17 requires that inspection results are recorded in a documented inspection schedule. Records must include: equipment tag, protection type, gas group, T-class, inspection grade performed, date, inspector identity, deficiencies found, classification, and action taken. These records are typically required for DSEAR compliance audits and insurance purposes.
Practising Inspection Decisions
EX Academy's 15 inspection simulations put you through the complete inspection process — work order, equipment data, deficiency identification, and classification — across a range of protection types, zones, and gas groups. This decision-based practice is the most effective way to prepare for the CompEx Ex03/Ex04 assessment.
Interactive inspection simulations, equipment selection decisions, and 1,185+ practice questions referenced to IEC 60079. Try free — no card required.
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