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Older High Voltage Switchgear: Managing the Risk

Authorised persons looking after electrical installations almost invariably have a high level of competence but many may not be aware of the risks involved in managing older switchgear. Fortunately, says Marcus Charter, Power Consultant at Schneider Electric, once this shortcoming is recognised, it can readily be addressed by having robust management processes and training programmes.

Let's not mince words – working with electrical switchgear always involves risks. Large amounts of energy are continuously available when the switchgear is in use and, under fault conditions, even more energy is likely to be released. In the unfortunate instance an operator is exposed to this energy they are likely to be maimed for life or even killed.

It is essential, therefore, not only that the equipment should be suitable for duty in hand when it is first installed, but that it should continue to be suitable for this duty as it ages. Make no mistake, should a switchgear assembly fail to contain the energy present, whether under normal or fault conditions, it is likely to fail catastrophically.

These significant risks associated with switchgear can, however, be controlled to a reduced level if that switchgear is well managed – which involves regular inspection, testing, maintenance, increased user familiarity and documentation – and correctly operated. The responsibility for ensuring that these issues are properly addressed falls to Authorised Persons who will have received appropriate training and be appointed through a lengthy assessment process by there organisation.

Sufficiently assessed and trained authorised persons will be well aware of the hazards posed by modern switchgear. They are also likely to be comfortable that modern equipment will operate safely, putting their faith in the modern technologies and techniques used to enhance safety, and also being reassured by knowing that the equipment is relatively new and has, therefore, suffered little wear or degradation since leaving the factory.

But what about older switchgear, especially if it is oil filled? The small but noticeable amount of rust on the chassis, the mildew in the termination box gasket – do these reflect the condition of the contacts, the operating mechanism, the fault containment and the arc dissipating components inside?
Is the operator risking their life when they operate the switch? How do they know whether to operate the switch or not? Is their decision based on guesswork, complacency or faith?

It must be none of these things. The basis for the decision has to be full confidence in an established properly managed switchgear system, which ensures that the equipment is correctly maintained, taking into account its age, type and dielectric type, and that any restriction notices have been appraised and appropriate action taken.

Let's take a look at some of the dangers specifically associated with the use of older switchgear. Among the most important are:

Lack of knowledge – users may not have enough knowledge to be aware of the potential risks involved with the operating the switchgear.
Overstressing – the switchgear may not be rated to handle present-day full load currents and fault levels
Modifications – the manufacturer may have issued recommendations for modifications to ensure that the equipment remains safe to operate. It is essential that these are implemented.
Dependent manual operating mechanisms – all switchgear currently in use must incorporate operating mechanisms that do not depend on the operator's strength and speed to make and break contacts. Any switchgear that does not meet this requirement is unfit for use.
Lack of proper maintenance – this is usually the result of oversight, but may also be due to limitations imposed by financial controllers in order to minimise shutdowns. It is important that maintenance of older switchgear takes into account the age and peculiarities of the equipment. In particular, as the equipment ages, more intrusive inspections are required.
Anti-reflex handles – these must be fitted to ensure that the equipment can only be operated fully in one direction (open or close), before the handle is re-oriented to allow operation in the other direction.

Addressing these issues involves implementing an effective switchgear management system. A very good starting point for this is Health and Safety Executive document HSG230 "Keeping Switchgear Safe". The guidelines contained in this document define records that need to be kept and keeping these records will ensure that:

The switchgear is not outside its managed life cycle
The maintenance cycle and the maintenance work carried out has taken into account the age of the switchgear
The maintenance has been fully and correctly completed
A full maintenance history is available
All restriction notices have been considered and, where necessary, appropriate actions have been implemented
The Switchgear is known to fall in line with latest requirements, such as independent manual operation, anti-reflex handles

It is worth noting that these records not only provide a framework for increasing the reliable and safe operation of the equipment, but also help to meet legal obligations, not least those related to ensuring that employees are protected from harm.

Record keeping is, of course, not the only requirement. It must be complemented by continued training of persons authorised to operate switchgear (authorised persons). Care must be taken, however, in selecting the training provider – it is important to choose an organisation that has in-depth knowledge and experience of the special issues involved with older switchgear, rather than an organisation that can only provide training relating to modern technology.

Naturally, the dangers of older switchgear that were mentioned earlier must also be directly addressed. This means, for example, that equipment with dependent manual operating mechanisms or which lacks anti-reflex handles must be immediately taken out of service and removed from site.

Taking these measures will help to maximise the safety and reliability of older equipment. In contrast, if the special needs of older switchgear are not properly considered, and if it is operated without due regard for its internal condition, or when it is outside its recommended life cycle, the consequences could be catastrophic.

It is always essential to remember that the operator's life is in their own hands when they operate switchgear. No assumptions should be made, therefore, and no pressure should be applied to operators to force them to carry out switching operations unwillingly.

Operators should always be confident, because of a well-structured management programme, that the switchgear is in a suitable condition to be switched safely. Implementing a switchgear management programme is not difficult, but it is often useful to seek advice and guidance from an expert in the field.

Hopefully this article has demonstrated that health and safety issues, far from being a subject for trivialisation, are an essential concern for everyone whose work involves electrical switchgear. Tackling these issues has many benefits. Reduction of hazards is the most important of these, but well-trained personnel and an effective equipment management regime will also result in reduced downtime and increased security of supply. Investing in health and safety, therefore, is a very sound business proposition

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