Ex Equipment Maintenance — Inspection and Repair Guide
Maintaining Ex equipment in hazardous areas requires a different approach from standard industrial equipment. The protection provided by Ex certification depends on the equipment remaining in its certified condition. Any maintenance that could alter the equipment's characteristics must be carried out with care and properly documented.
What Can Be Done in the Field
Routine maintenance that can be carried out by a competent electrician in the field includes:
- Cable gland replacement — like-for-like replacement with an equivalent certified gland
- Stopping plug replacement — replacement with a certified plug of the same type and rating
- IP gasket replacement — replacement with the correct gasket as specified in the equipment documentation
- Bolt replacement — replacement with bolts of the correct grade and dimensions as specified
- Terminal maintenance — replacement of ferrules, conductor identification, terminal tightening
- Lamp replacement — in Ex e or Ex d luminaires, replacement with the type specified on the equipment label
What Requires Specialist Repair
Some maintenance activities can only be carried out by the equipment manufacturer or an authorised repair facility:
- Flamepath repair — any work on the flamepath surfaces of Ex d equipment requires specialist machining and re-certification
- Enclosure modification — adding or modifying cable entries, drilling additional holes
- Winding replacement on Ex motors — requires re-testing and re-certification
- Certificate amendment — any change from the original certified design
Any replacement component must be like-for-like — the same type, rating, and certification as the original. Substituting a non-barrier gland for a barrier gland, fitting an IIB stopping plug in an IIC enclosure, or using a non-certified bolt on an Ex d cover are all non-compliances that compromise the equipment's protection and create Category X deficiencies.
Documentation
All maintenance activities on Ex equipment must be documented — what was done, who did it, what components were used (with certification references), the date, and any observations about the equipment condition. This documentation is required for DSEAR compliance and supports future inspection decisions.
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