LV & HV Equipment Type Test Certification: Essential to Reliable Electrical Supply

By Craig Diack-Evans, Director of Engineering, ASTA BEAB Certification Services

Nobody doubts the need for electricity - the belief that the progress of civilisation is dependent on electrical power comes from the very rapid advances made in developed countries this century. Providing an electrical supply leads to a growth in wealth simply by giving opportunities for improvement in business, education and leisure. It is hard to believe therefore that only 30% of people in the Third World have a supply and that there is still 70% of the population of China without electricity.

Experience in many countries is showing that supplies are often haphazard and unreliable which lead to economic and social problems. Failed safety devices separately or in switchgear may be removed or overridden, simply to keep the plant running to meet the urgent customer demand. This also has the effect of removing the urgency for repair and such solutions, unfortunately become permanent answers.

Standards

To prevent potential problems, particularly the damage to persons or property but also economic and social problems, it is essential purchasers and contractors throughout the electricity supply chain specify equipment that is the subject of recognisable and reliable certification or approval and from certified quality assured sources. The failure of plant can close down hospitals, schools, sewage pumping stations etc. - the catalogue is endless - just think about it!

The need for European and Internationally recognised third party certification of electrical equipment is apparent to both the manufacturer and the user. The manufacturer so that he can demonstrate compliance with the standards and the user so that he can ensure safe and reliable installations; it is better to find the problem before the equipment is put into service and to re-design the product to cope with the conditions specified by the purchaser.

The reasons for testing

By nature of its application, equipment may be installed for many years before being called upon to operate to their intended capability. Short-circuit faults on LV and HV equipment such as circuit-breakers, fuse switches, controlgear assemblies, starters etc. can cause explosions, fires, personal injury and loss of supply if the products are not safe. Take for example, a short-circuit fault on the incoming supply to the assembly. Any marginal performance in the design of the assembly may not be immediately evident. With type-tested assemblies this concern is eliminated because type testing has proved the design. Therefore, there are no

Considerations

Dielectric strength, earthing provisions, even the ambient operational temperature of equipment needs to be considered - all are important aspects of component and equipment performance that are required by the standards.

The manufacturer should ensure that he has verified the design, controls the manufacturing processes and tests the finished products. Assembly manufacturers should select correctly rated components and equipment that have been certified or approved and should have a representative assembly independently tested. The end user, consultant or installer, should only install correctly rated equipment that has been independently verified and should have the installed equipment tested and commissioned.

Duty of Care

What does duty of care mean? It means that if you are operating in this specialised field you must use your knowledge to the best of your ability. The manufacturer has a duty of care to make safe products. The wholesaler has a duty of care to select safe products - but how does he know which ones are safe and which ones are not? What liability will he attract? What if you cannot take action against the manufacturer or importer? The specifier/consultant who defines the parameters and selects the equipment for the job has a duty of care similar to the wholesaler. The installer who installs and commissions the equipment could completely change the parameters and safety of the equipment. The end user for maintenance of the equipment either himself or by sub-contract, could do the same. So liability is the important thing to consider and having certified product is taking the highest "duty of care".

Testing

The best advice is to have the equipment independently tested. You do not have to test every piece of equipment that you make, only a representative sample. This is your evidence that the equipment will be safe in use. It should be noted however, that there is no mandatory requirement for manufacturers to have their assemblies type-tested and certified. It is at very least though - good practice.

Type tests should be conducted at independent facilities accredited to ISO IEC 17025 "General requirements for the competence of testing and calibration laboratories" by a competent body.

In conclusion, with so much of the world's population still without electricity in 2005, it is vital that as the electrification process continues, manufacturers, consultants, installers and suppliers all work together to make electricity supply safe and reliable, enabling as many people as possible to enjoy the benefits of more efficient business, education and leisure - now and in the future.

Opting to produce or use equipment that has been tested and certified contributes to those efforts, minimises the chances of supply disruption, leading to a loss of opportunities, wealth or even life. Safe and reliable electricity supply and generation equipment will ultimately help us to build communities and to support the manufacturing industries that provide continuing employment and wealth.

About Craig Diack-Evans:

Craig has extensive experience in all aspects of engineering from design to commissioning on sites throughout the world having started his career as an apprentice with GEC. Since joining ASTA BEAB, Craig has also gained considerable experience in the field of third-party certification and testing and has achieved an International profile and reputation in this field. Craig is an experienced assessor of management systems and provides his technical assessment expertise to other organisations. He is also authorised to witness tests at accredited laboratories on behalf of ASTA BEAB and other organisations.