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Busbar coating materials

Coating powders for busbars and switchgear applications

AIS and GIS substations up to 38KV

Medium Voltage

Medium Voltage Busbar Basics

Medium voltage busbars are used in primary switchgear equipment used to conduct electrical power from the grid to the end user. The switchgear equipment may contain single busbar or double busbars, and the types of switchgear may be solid-, air-, or gas-insulated. In most cases, the rated voltage of medium voltage switchgear is between 12kV and 38kV, which for coating purposes is considered pretty high voltage, since the effect of using the wrong insulation material could be disastrous, and in some cases even fatal. The goal of the coating powder is to insulate the busbars from each other and to prevent dangerous arcing faults.

What is critical with medium voltage busbar coating is to ensure that:

  • The epoxy coating powder has the correct dielectric properties including dielectric strength and arc resistance
  • The epoxy coating powder coats the busbar to the correct thickness

Epoxy coating powder thickness of medium voltage busbars typically always needs to be in excess of 2.8mm (110 mils). This is not an easy task. Some suppliers may supply epoxy coating powders, but when applied to the medium voltage busbar, they do not build up to the required thickness, or if they do, the epoxy sags, compromising both the ability to closely position the busbars as well as to provide the sufficent level of electrical insulation. It is imperative therefore to make sure that the epoxy powder you select has the ability to build to more than 2.8mm without sagging.

CAPLINQ Epoxy Coating Powders for Medium Voltage Busbars and Switchgear Equipment

For many years, CAPLINQ, Inc. has supplied a range of epoxy coating powders developed for medium voltage (600V – 38,000V) bus bar and switch gear applications. In the USA, CAPLINQ is one of the few epoxy coating powder suppliers qualified for use in Power Distribution Switch Boards. Given the critical nature of the application, the time and costs involved to pass UL-certification, major Power Management Companies reply on CAPLINQ and their family of UL-listed epoxy coating powders. All the products offered by CAPLINQ for busbar applications are UL-listed.

Three products stand out in the CAPLINQ product line for medium voltage busbar applications: DK15-0606, DK15-0907 and DK19.

The "One Powder Solutions": DK15-0606 Tan and DK15-0907 Red

Changing equipment and changing epoxy coating powders is not a trivial task. If you are manufacturing both low voltage and medium voltage busbars, wouldn't it be great to only have to use one product for both? This is exactly the purpose of these two epoxy coating powders. DK15-0907 Red for Low and Medium Voltage Busbars is a one powder solution in red and DK15-0606 Tan for Low and Medium Voltage Busbars is a tan-colored (some people call it dark beige) powder that is likewise suitable for both low voltage and medium voltage busbars.

Fast, thick-building DK19 Red for Medium Voltage Bus Bar Applications

If you are only manufacturing medium voltage busbars, or you have a dedicated line specifically for medium voltage busbars, then DK19 Red for Medium Voltage Busbars is an excellent example of an industry standard epoxy coating powder for medium voltage busbars. It is impressive to see not only how thick this material can build on a busbar, but the speed and uniformity at which it does this. DK19 Red can build in excess of 5mm thickness and it builds the thickness at a rate in excess of 175 microns per second. This speed puts the DK19 Red in a class of it's own and no other epoxy coating powder even comes close.

DK19 Red also has the best-in-class arc resistance greater than 170s and is another reason why it has been used for years by major power management companies busbars and switchgear applications that pass up to 38,000 Volts. Colored in red, the DK19 meets UL94 class V-0 and can be dipped multiple times to achieve the desired coating thickness. It is also available with longer gel times if needed for larger busbars that need a longer time to achieve a uniform coating thickness.

What makes the DK19 Red so great for medium voltage busbars is its downfall with low voltage busbars. The thick builds needed for medium voltage busbars are not needed and not wanted for low-volatge busbars as it impacts the stacking density in low-voltage switchgear.