Electrical installations: inspection and maintenance

Standard EN/IEC 60079-17 covers factors directly related to the inspection and maintenance of electrical installations within hazardous areas only, where the hazard may be caused by flammable gases, vapours, mists, dusts, fibers or flyings.
This standard stipulates that the inspection and maintenance of installations shall be carried out only by experienced personnel, whose training has included instruction on the various types of protection and installation practices, the requirements of this standard, the relevant national regulations/company rules applicable to the installation and on the general principles of area classification.
Three inspections are normally requested:
• initial inspection before plant or equipment is brought into service,
• regular inspections in time,
• inspection following any adjustment, maintenance, repair, reclamation, modification or replacement.
Frequency of inspection
The determination of the time interval between inspections shall be taken into account the process and the factors effecting the deterioration of equipment (susceptibility to corrosion, exposure to chemicals or solvents, likelihood of
accumulation of dust or dirt, likelihood of water ingress, exposure to excessive ambient temperature, risk of mechanical damage, exposure to undue vibration, training and experience of personnel, likelihood of unauthorized modifications or adjustments and likelihood of inappropriate maintenance, for example that which is not in accordance with the manufacturer's recommendation).
But the interval between periodic inspections shall not exceed three years without seeking expert advice.
Degree of inspection
• Visual inspection: faults directly visible such as missing buttons or missing gasket, not well screw cable entries,…
• Close inspection: visual inspection and in addition detection faults (Close inspection does not normally require the enclosure to be opened, nor the equipment switched off).
• Detailed inspection: such as loose connections, detected after opening the enclosure.


“Ex d” equipment:
It is preferable to obtain new parts from the manufacturer.
Particular attention shall be paid to the correct assembly of flameproof enclosures after repair or overhaul, in order to ensure that the flameproof joints comply with the requirements of the standard. The flameproof enclosure are not gasketed thus they may be protected by the use of grease, non-setting sealing compound or non-hardening tape applied externally in accordance with IEC 60079-14.The drilling of holes into a flameproof enclosure is forbidden. No re-cement or repair light-transmitting parts shall be made and only complete replacement assemblies, as specified by the manufacturer, shall be used. No modification affecting the explosion protection shall be carried out on parts of a flameproof enclosure.
“Ex n” or “Ex e” equipment:
Care shall be taken when refurbishing terminations to maintain clearance and creepage distances. Any replacement terminals, bushings or parts should be obtained from us or shall conform to the relevant certification documents only for the enclosure. It is preferable to obtain new parts from the manufacturer to guarantee the preservation of the degree of ingress protection and temperature classification as stipulated on the certification label.
All equipment:
For equipment with a gasket, replacements shall be of the same materials and dimensions as the original. Any proposed change of material shall be referred to the equipment manufacturer, user or certification authority. For luminaries:
Light-transmitting or other parts made from plastics shall not be cleaned with solvents. Household detergents are recommended for this purpose. The maximum wattage of lamps specified shall not be exceeded. Care shall be taken when changing surface finish, paint, etc., as this may affect the surface temperature of the enclosure and thus the temperature classification. Care shall be taken to ensure that the specified type of protection and degree of ingress protection are maintained.