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Insulators, bushings and surge arresters

The danger for the people deriving from contact with active parts has been studied and regulated from international committees since several decades, whose result has been a series of standards prescribing the features of the insulation of each electrical component installed in the grid, depending on its rated voltage and other characteristics (BIL). Even if sometime the insulation is part of the component itself, other times is a separated part developed by specialized manufacturers and regulated by specific standards. Insulators are designed for every kind of component, e.g. for transformer bushings, circuit breakers, surge arresters or for support of overhead lines, (suspension- and tension insulators) in the energy grid. However, in particular conditions, an overvoltage can flow in some parts of a grid, putting in danger the insulation withstand of the interconnected components. This risk is limited by surge arresters, whose task is to redirect the overvoltage to earth. For testing each of these components, laboratory tests are necessary to confirm that the product is verified for the specified application according to the international standards and utilities specifications.

What we do

CESI Group can provide tests on MV and HV insulators, bushings and surge arresters according to internationally recognized standards:

Bushings ​ ​
IEC 60137
IEC 61109, IEC 60168, IEC 60383, IEC 61952, IEC 62231, IEC 62217, IEC 61325, IEC 60507, IEC 60437, IEC 61425, IEC 60437, IEC 61245, IEC 61462, IEC 61467
​Surge Arresters
IEC 60099

Further tests according national standards and specific customer requirements are also available on request.

Where we do it

Our testing laboratories are distributed over the three platforms and include:


CESI Group has started to deal with Insulators tests since the 1967 SACOI project, with experiences on oil-insulated ceramic systems, then with tests on paper impregnated systems and, since 1993 (the first time in the world), with extruded insulation systems (Project BEWAG) and composite materials. CESI Group today is among the world leaders for this typology of tests on electrical equipment.
















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