BS 06626:2010 pdf download – Maintenance of electrical switchgear and controlgear for voltages above 1 kV and up to and including 36 kV – Code of practice
3.16 overhaul comprehensive set of examinations and actions carried out in order to maintain the required level of availability and safety of an item NOTE 1 Overhaul may be performed at prescribed intervals of time or number of operations. NOTE 2 Overhaul may require a complete or partial dismantling of the item. [BS EN 13306:2001, 8.6]
3.17 post-fault maintenance maintenance which might be necessary after a specifed number of fault clearance or making operations
3.18 preventive maintenance maintenance carried out with the objective of preventing failure NOTE It may include routine or non‑routine maintenance.
3.19 routine maintenance maintenance organized and carried out in accordance with a predetermined policy or plan to prevent failure or decide the likelihood of an item failing to be in an acceptable condition
3.20 servicing work carried out to ensure that the equipment is kept in an acceptable condition, which usually does not involve any dismantling, and is typically limited to cleaning, adjustment and lubrication 3.21 switchgear a general term covering switching devices and their combination with associated control, measuring, protective and regulating equipment, also assemblies of such devices and equipment with associated interconnections, accessories, enclosures and supporting structures, intended in principle for use in connection with generation, transmission, distribution and conversion of electric energy [IEC 60050-441:1984+A1, 441-11-02]
4 Maintenance policy It is the asset owner’s responsibility to ensure that there is an effective maintenance policy. An example of this is described in PAS 55. Whilst there is no legal requirement for maintenance at any particular interval, there is a legal requirement that the system and its parts continue to be safe. NOTE Attention is drawn to the Electricity at Work Regulations 1989. See the Health and Safety Executive (HSE) publication HSR 25 Memorandum of guidance on the Electricity at Work Regulations 1989 . There are several aspects of the risk assessment concerning the scope, content and timing of the maintenance. Evidence is necessary to make a judgement of what maintenance is required ranging from functional checks to complete replacement. The performance of the system, operational history, environmental exposure, physical condition, age and consequences of failure all provide evidence. Experience from similar systems gives useful guidance on potential performance. Manufacturers can be expected to provide guidance about maintenance, but clearly different practical applications over the lifetime of the system can give rise to failure modes that the manufacturer might not be aware of. Further guidance is provided by competent organizations [e.g. the Health and Safety Executive (HSE) or electrical consultants], standards and industry recommendations.
The initial maintenance interval and its content should be as advised by this guidance. Subsequent experience should be recorded and used to update maintenance policy. It is key to the continued safe operation of the system and its parts that there is adequate evidence to justify the maintenance policy. This may involve progressive sampling of the equipment to assess the continuing condition of the equipment and understand potential failures. If the maintenance interval is extended and a system failure or fault can have signifcant consequences, then adequate precautions should be taken to ensure that such faults can be anticipated and the consequences prevented so far as is reasonably practicable. Thus it is essential that any maintenance policy takes into consideration the application of the equipment, its use, environment, changes in operation and consequences of failure. Options for maintenance can be restricted by lack of available parts. Many manufacturers are no longer in business. Their equipment might be supported by other manufacturers, but such support can be limited. Guidance concerning the decisions and available actions for maintenance are given in HSE publication HSG 230 Keeping electrical switchgear safe .