Properties and advantages of insulators for Switchgear

In 1978, Poinsa came into being with a clear purpose, to reach the forefront of the European market in terms of the manufacture of electric ceramic insulators. From then onwards, our ethos has been based on providing quality and service to our clients beyond client expectations, flexibility and customisation of our insulating solutions and investment in technological processes. We are specialists in the manufacture of insulators operating at high, medium and low voltage in the markets for switchgear, transformers, railways, research projects and tailor-made products.

In compliance with international legislation in force, and at the same time adapting to clients’ in-house requirements, our ceramic insulation solutions adapt to any electrical environment that requires them. Support insulators for voltages up to 420kV of rated voltage.

Properties and advantages of insulators for switchgear

Column model supports have successfully replaced those named “capped” or “base-standing” supports for all types of electrical facilities thanks to their multiple advantages.

  • Reduced number of metallic elements per column.
  • They are more compact, meaning to fewer number of units are required.
  • Greater escape routes within the same space.
  • Sturdy body without holes, eliminating the risk of electrical perforations.
  • No internal breakages are noted as to result of the different dilatation coefficients between the porcelain and the internal metallic parts.
  • No radio or television interference takes place.

Manufacturing process

The manufacturing process of insulators for switchgear depends, mainly on the demands in terms of electrical insulation and mechanical resistance, bearing in mind both the situation, as well as the location of the same.

To achieve this, to series of standard support insulators has been designed taking into account the following features:

  • Maximum rated voltage.
  • Surge withstand capacity.
  • Voltage withstood in rainy conditions at 50 Hz.
  • Maximum bending strength load.
  • Minimum escape routes according to pollution levels CEI60815 (mm).
  • Attachment of the fastenings to the upper or lower part.
  • Enamel colouring.

Support insulators

Our catalogue is divided into two major groups for insulators for switchgear: Exterior support insulators and interior support insulators.

Types of exterior support insulators

The exterior support insulators are sub-divided in accordance with whether or not they are fitted with external or internal fastenings.

Exterior support insulators with external fastenings

Two different types of support insulators are distinguished between with external fastenings in line with their maximum rated voltage:

  • From 6 to 24 kV
  • From 28 to 36 kV
  • From 38 to 52 kV
  • From 66 to 100 kV
  • From 110 to 170 kV
  • From 245 to 420 kV

Exterior support insulators with internal fastenings

Different support insulators are available with internal fastenings according to their maximum rated voltage.

  • From 6 to 12 kV
  • From 15 to 24 kV
  • From 30 to 36 kV
  • From 10 to 40 kV

Types of interior support insulators

Within the group of interior support insulators, there are two types:

  • Insulators with maximum rated voltage from  6 to 17.5 kV.
  • Insulators with maximum rated voltage from  15 to 52 kV.

For further information, please refer to the technical specifications given in our catalogue on insulators for switchgear.