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 a 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 sufficient 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.

Epoxy Coating Powders for Medium Voltage Busbars and Switchgear Equipment

For many years, we have supplied a range of epoxy coating powders developed for medium voltage (600V – 38,000V) bus bar and switch gear applications. 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 rely on CAPLINQ and their family of UL-capable epoxy coating powders. All the products offered by CAPLINQ for busbar applications are UL-capable. Certification can be provided after consultation with our sales team.

LINQSOL BCP1507 is The "One Powder Solution"

LINQSOL BCP-1507 with its optimized gel time and flow ,builds up quickly and performs excellent coating results. With a wide coating thickness range of 0.1 ~ 2.0 mm, it could be used for both low (600V) and medium-voltage (38kV) busbar applications. Colors are available in orange, red, black, blue, green.

It is especially suitable for EV busbars and small busbars applications. The low heat capacity of small busbars limit the dipping times, thus it requires coating powders low pick-up temperature and high build rate, which BCP-1507 aims at. BCP-1507 meets the UL 746B Relative Thermal Index (RTI) of 130°C and CTI 600V.  For large busbar applications, we recommend BCP-1509. 

BCP-1507 Fluidized Bed Coating Performance 

Preheat Temperature	Dip Times	Minimum Coat Thickness	Breakdown Voltage Pass
200°C	1	0.43 mm	>20 kV
240°C	1	0.43 mm	>20 kV
240°C	2	0.48 mm	>20 kV
240°C	3	0.70 mm	>20 kV
240°C	4	0.85 mm	>20 kV
240°C	8	1.30 mm	>20 kV

Busbar for testing: Aluminum strip (75mm x 50mm x 5mm)

Breakdown volatge test: DC holiday detector

OBSERVATION

• Coating appearance: Smooth, no-sag, no-dripping, great edge coverage
• Coating process: Quick build rate on thickness
• Suitable thickness: both thin and thick thickness (>1mm)

DISCUSSION

BCP-1507 presents excellent coating performance with dielectric strength. It is highly potential to coat more than 2mm on large size busbars or copper busbars.

 

Fast, thick-building LINQSOL BCP-1509 

If you are only manufacturing medium voltage busbars, or you have a dedicated line specifically for medium voltage busbars, then LINQSOL BCP-1509 for medium voltage busbar applications 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.

LINQSOL BCP-1509 can build in excess of 3mm 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.

LINQSOL BCP-1509 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 a Reddish Brown, the BCP-1509 meets UL94 class V-0 and can be dipped multiple times to achieve the desired coating thickness. This product can be equivalent to DK19.

Medium Voltage Busbar Coating powder Selection Guide