CharCoat IC RTV Silicone Insulator Coating – Anti Pollution-Flashover for HV Insulators
Sprayed RTV silicone that makes insulator pollution water-repellent, preventing flashover from 11 kV to 765 kV.
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CharCoat IC is a room-temperature-vulcanised (RTV) silicone elastomer developed by CharCoat Passive Fire Protection and Mace Technologies with the Electric Power Research Group of the University of the Witwatersrand, to prevent pollution flashover on high-voltage outdoor insulators. Its strong hydrophobicity transfers to the dirt layer that settles on the insulator, so moisture beads instead of forming a conductive film — limiting leakage current and stopping the dry-band and partial-discharge sequence that leads to flashover. Made by CharCoat Passive Fire Protection, whose coatings are applied in more than 40 countries.
At a glance
- Product: CharCoat IC insulator coating
- Type: two-part RTV silicone elastomer, sprayed
- Contact angle: 122° (highly hydrophobic)
- Dielectric strength: 64 kV/mm at 23 °C
- Service record: since 1991, 11 kV substations to 765 kV transmission and 533 kV DC converter stations
- Thickness: 0.3–0.5 mm optimum
- Warranty: 10 years, as stated by CharCoat
Why choose CharCoat IC
- Stops pollution flashover — CharCoat reports no flashovers at any treated site since 1991.
- Proven in the worst pollution — marine salt fog, coastal desert, acidic industrial fall-out, cement dust and sugarcane-burning areas.
- Hydrophobicity that recovers — fast recovery after arcing and corona, and transfer to the contamination layer.
- Energise immediately after coating; cure is independent of humidity with practically no shrinkage.
- Tested to CPRI specification for hydrophobicity recovery, alongside ASTM arc and tracking tests.
Specifications
- Chemistry: two-part RTV silicone elastomer (catalyst added before application); non-oxime cure, no by-products, shrinkage < 0.1%
- Hydrophobicity: 122° water contact angle; fast transfer to contaminating layers and fast recovery after arcing
- Dielectric strength: 64 kV/mm at 23 °C
- Arc resistance: > 185 seconds (ASTM D495)
- Tracking and erosion: > 470 minutes at 2.5 kV (ASTM D2303)
- Hydrophobicity recovery: tested to CPRI specification: HC1–HC2 after 48 hours
- Resistance: corona, oil, ozone, chemicals and petrol; ageing resistant; 100% UV resistant; temperature resistant down to -50 °C after full cure
- Adhesion: glass, ceramic and resin surfaces; CharCoat IC primer supplied with every coating purchase
- Application: spray, optimum 0.3–0.5 mm; skin-over about 15 minutes; pot life 1 hour at 23 °C; equipment can be energised immediately after coating
Where it is used
- Substation post, bushing and apparatus insulators
- Transmission and distribution line insulators
- Coastal, desert and industrial sites with heavy contamination
- Near cement plants, steel plants and power-station fall-out
- Agricultural areas with sugarcane burning or conductive fertilisers
CharCoat IC versus washing or greasing insulators
- Versus periodic washing: the coating keeps working between visits instead of the insulator re-polluting until the next wash.
- Versus greasing: a cured silicone rubber layer rather than a grease that must be removed and renewed.
- Versus replacing insulators with composite ones: gives existing porcelain and glass insulators a silicone surface without replacing them.
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Frequently asked questions
How does CharCoat IC prevent flashover?
It makes the insulator surface and the pollution layer on it water-repellent, so no continuous conductive moisture film forms; leakage current stays low and the dry-band and partial-discharge steps that lead to flashover do not develop.
Which voltages has it been used on?
From small 11 kV substations to complete 765 kV transmission stations and 533 kV DC converter stations.
Can the equipment be energised straight after coating?
Yes — CharCoat states equipment can be energised immediately after coating.
How thick is the coating?
The optimum is 0.3–0.5 mm, sprayed.
Is a primer needed?
A primer is recommended for a strong permanent bond to ceramic, glass and resin, and CharCoat supplies it with every coating purchase.
Where can I buy it in India?
From Jai Enterprises, which supplies across India from Bhilai and Raipur, Chhattisgarh. Call +91 9340081159.
How to order
Supplied by Jai Enterprises, despatched from Bhilai and Raipur, Chhattisgarh, to sites across India. To request a price, call +91 9340081159 or send an enquiry from this page with your quantity and site details, and we will confirm availability, lead time and the right model for the job.
Applications
Availability: Enquiry-based — contact us for stock and lead time.
