Switchgear Insulation Products by ACC Insulations
Switchgear is the collective term for the electrical disconnect switches, fuses, and circuit breakers used to control, protect, and isolate electrical equipment. The insulation materials inside a switchgear panel are as critical as the switching devices themselves — they maintain the required clearance and creepage distances between live phases and earth, resist electrical arcing, and provide the mechanical framework that holds busbars and conductors in position under short-circuit forces.
ACC Insulations supplies a comprehensive range of switchgear insulation materials for LV, MV and HV systems, manufactured in Nashik, India. Our materials handle the electrical stress, mechanical loads, and thermal variations encountered inside switchgear cabinets and metal-enclosed switchgear assemblies — available in standard sheet sizes or custom cut and machined to your panel design drawings.
Why Insulation Is the Backbone of Every Switchgear Panel
When a fault occurs in an electrical system, the switchgear must interrupt the circuit quickly and safely. In that split second, the insulation materials face extraordinary stresses: intense heat and UV radiation from the arc, massive electromagnetic forces from short-circuit currents, and the risk of arc flash propagation if an insulation barrier fails. Well-specified switchgear insulation materials prevent all of these failure modes.
- Safe electrical isolation: Maintains specified clearance and creepage distances between phases (R-Y-B) and between live parts and the earthed enclosure under continuous rated voltage.
- Arc containment: High-dielectric-strength materials like FR-4 epoxy laminate (45 kV/mm) resist arc propagation during fault conditions, protecting adjacent components.
- Mechanical support: Epoxy laminate busbar support blocks hold conductors rigidly in position even under the peak mechanical force of a short-circuit current (up to 100 kA in MV systems).
- Thermal stability: Class F (155°C) and Class H (180°C) rated materials maintain dielectric integrity at the elevated temperatures generated during switching and continuous load.
- Tracking resistance: High-CTI materials resist surface carbon tracking in contaminated environments — critical for switchgear in industrial, coastal, and high-humidity locations.
Insulation Requirements by Voltage Class
The materials required depend heavily on the voltage class of the switchgear. Higher voltage classes demand greater creepage distances, higher dielectric withstand, and stricter material grades.
Low Voltage Switchgear
MCCBs, ACBs, MCBs, MCCs, distribution boards. FR-4 laminate, FRP sheets, phenolic boards, DMD composite paper for flexible wrapping.
Medium Voltage Switchgear
Vacuum circuit breakers, ring main units, SF6 panels. G-10/G-11 epoxy laminate, FRP pultruded profiles, machined epoxy arc chute parts.
High Voltage Switchgear
GIS substations, SF6 circuit breakers, disconnect switches. Precision-machined G-11, FRP cylinders — tight dimensional tolerances essential.
Each FR-4 epoxy laminate barrier maintains the required creepage distance between phases per IEC 60947, and resists arc propagation during a phase-to-phase fault. Dielectric strength of 45 kV/mm provides a substantial safety margin above LV and MV impulse withstand levels.
Our Switchgear Insulation Material Range
FR-4 & G-10 / G-11 Fibre Glass Epoxy Laminates
The most widely specified switchgear panel insulation board globally. FR-4 glass fibre epoxy laminate delivers a dielectric strength of 45 kV/mm, UL94 V-0 flame retardancy, low moisture absorption (<0.1%), and high CTI up to 200. Used as busbar support boards, phase barriers, arc chute insulation, terminal boards, and relay mounting boards. G-11 high-temperature epoxy laminate provides superior performance up to 180°C for MV and HV switchgear applications.
FRP Sheets & Pultruded Profiles
Fibre Reinforced Polymer (FRP) sheets provide a moisture-resistant, corrosion-immune alternative to metal enclosure partitions — used in outdoor switchgear, cable compartment partition walls, busbar enclosure panels, and structural busbar support frames in MV switchgear (non-magnetic, so no eddy current heating).
Industrial Composite Insulation Boards
Paper base (P2, P3) and fabric base (F2, F3) phenolic laminates for lower-voltage distribution boards where cost-effectiveness is important. Fabric base grades preferred for machining of complex profiles — circuit breaker mounting plates, guide rails, and structural spacers.
Precision-Machined Insulation Components
ACC Insulations provides CNC machining of insulation components to your panel design drawings — busbar support bars (drilled and countersunk), phase separator plates, arc barriers, contact insulator bushings, HRC fuse holder insulation bases, and MCC panel base plates with wiring duct slots.
Key Material Properties — Quick Reference
Switchgear Types & Applications
Our insulation materials serve the full spectrum of switchgear and power distribution equipment:
LV Switchgear Panels
MCB distribution boards, ACB panels, MCC motor control centres
MV Switchgear
Vacuum circuit breaker panels, ring main units, VCB drawout assemblies
HV Switchgear
GIS substations, SF6 circuit breakers, HV disconnect switches
Busbar Trunking
Busbar supports, busway insulation blocks, phase segregation
Control & Protection
Relay panels, protection relay boards, metering compartments
Power Electronics
VFD panels, UPS enclosures, solar inverter switchgear boards
Material Selection Guide for Switchgear Engineers
Key Benefits
- High dielectric and arc resistance: FR-4 and G-11 epoxy laminates at 45 kV/mm with UL94 V-0 flame retardancy resist arc propagation during fault conditions.
- Excellent mechanical rigidity: Tensile strength up to 450 MPa (FR-4) holds busbar supports rigid under short-circuit electromagnetic impulse forces.
- Thermal stability under load: Class F (155°C) and Class H (180°C) rated materials maintain dielectric integrity at elevated operating temperatures.
- Low moisture absorption: <0.1% water absorption in FR-4 and G-10 grades ensures creepage distances are maintained in humid switchroom environments.
- Custom manufacturing: CNC cut-to-size, drilling, milling, and threading to your exact panel drawings — supplied as ready-to-assemble components.
- IEC and IS compliance: All materials comply with IEC 60947, IEC 60893, IS 8623, and relevant IS specifications.
Why ACC Insulations for Switchgear Insulation?
- Proven expertise across all voltage classes: We supply LV panel builders, MV switchgear OEMs, and HV equipment manufacturers — each with different material requirements, all serviced from one source in Nashik, India.
- Full portfolio from one supplier: FR-4, G-11, FRP sheets, FRP pultruded profiles, phenolic laminate boards, and machined components — covering every insulation requirement in a switchgear panel.
- Ready-to-assemble machined components: Finished busbar supports, phase barriers, and arc chute parts already drilled, milled, and dimensionally verified — eliminating an in-house machining step.
- Reliable quality and supply: Every batch tested for dielectric strength, dimensional accuracy, and mechanical properties before dispatch — consistent quality means no rejections on the panel assembly line.
- Technical support: Our engineering team helps you specify the correct material grade for your switchgear voltage class, ambient conditions, and mechanical requirements.
Engineering Tools Suite
Calculate precise phase-to-phase clearances, creepage distances, and dielectric barrier thickness requirements for your LV, MV or HV switchgear assemblies using our interactive calculators.
Frequently Asked Questions
Insulation in switchgear panels provides electrical isolation between phases and between live parts and earth, arc containment during fault conditions, mechanical support for busbars under short-circuit forces, and creepage distance maintenance through high-CTI materials that resist surface tracking in contaminated environments.
LV switchgear uses FR-4 glass fibre epoxy laminates, FRP sheets, and phenolic laminate boards. MV switchgear requires G-10 and G-11 epoxy laminates with higher arc tracking resistance and FRP pultruded profiles for structural busbar supports. HV switchgear uses precision-machined G-11 components and FRP cylinders to maintain the large creepage and clearance distances required by IEC 60947.
CTI (Comparative Tracking Index) measures how resistant an insulation material is to surface tracking — the formation of conductive carbon paths when contaminated by dust or moisture. A higher CTI means longer resistance to tracking failure. FR-4 achieves CTI 175–200 (IEC Group IIIa), while higher-performance grades reach CTI 400+ (Group II). Specifying the correct CTI group for your switchgear environment is critical to long-term panel reliability.
For LV switchgear (up to 1 kV), FR-4 laminate at 45 kV/mm provides a generous safety margin. For MV switchgear (1–36 kV), materials must withstand lightning impulse withstand voltage (LIWV) tests per IEC 60947-2, requiring inherent dielectric strength above 30 kV/mm. For HV equipment above 72 kV, machined components must pass full LIWV and power frequency withstand tests to IEC 62271. ACC Insulations can advise on the correct laminate thickness for your voltage class.
Yes. ACC Insulations has in-house CNC machining capability to produce busbar support bars, arc barriers, phase separator plates, contact insulators, and structural spacers to your panel design drawings. Materials available include FR-4, G-10, G-11, FRP sheets, and phenolic laminate grades. Submit your drawing through our contact form and we will respond within one business day.
