1 Physics: epoxy that behaves like SF₆—almost
Epoxy resin (εᵣ ≈ 3.8) provides 25 % higher dielectric strength than air at atmospheric pressure and 3× higher than mineral oil. When vacuum interrupters are cast inside an epoxy pole, the phase-to-phase spacing drops from 600 mm (air) to 200 mm—comparable to SF₆ GIS but without the 0.6 MPa pressure vessel. The cast resin also acts as a thermal spreader: finite-element modelling shows a 30 % reduction in hot-spot temperature compared with open-air busbars of the same cross-section .
2 Market pulse: USD 3.42 B in 2024, 6.8 % CAGR to 2033
According to DatIntelo, the global solid insulated switchgear market was valued at USD 3.42 billion in 2024 and is projected to reach USD 6.26 billion by 2033, growing at a CAGR of 6.8 % . Asia-Pacific accounts for 38 % of demand, driven by urbanisation and renewable integration, while Europe represents USD 900 million, spurred by SF₆ phase-out mandates .
3 Environmental ledger: 480 kg CO₂-eq avoided per bay
A 36 kV, 2,500 A bay built with virgin copper and SF₆ embodies 1.8 t CO₂-eq; the same bay in SIS with 75 % recycled aluminium and epoxy encapsulation totals 0.37 t CO₂-eq—a 60 % reduction before energisation . Over 25 years the SF₆ alternative would leak an additional 63 t CO₂-eq; the SIS bottle leaks zero.
4 Shielded solid insulation: accidentally touchable
A conductive layer sprayed on the epoxy surface holds the entire pole at earth potential, meeting IEEE 1247 “touch-safe” requirements . During a 2024 audit at a German automotive plant, operators could perform visual inspections without switching the feeder to earth—cutting downtime by 40 minutes per intervention.
5 Modular architecture: 50 MW in 14 m²
Single-phase epoxy poles snap into 430 mm-wide modules—1/6 the footprint of traditional AIS KYN61 gear . A 50 MW data centre that once needed a 120 m² switch-room now fits inside a 14 m² corner, freeing white-space for revenue-generating servers.
6 Smart embedded sensors: IoT inside the pole
A 0.2 W MEMS sensor harvests energy from the 50 Hz magnetic field and logs temperature, vibration and contact travel every millisecond. When contact bounce duration drifts > 8 % from the factory “birth-curve,” the chip bursts 48 bytes via LoRa—ordering a spare bottle four months before dielectric strength collapses. Over 1,000 breakers in Finland have cut unplanned outages by 37 %, saving an estimated €1.2 M in lost urban commerce .
7 All-climate validation: −50 °C to +70 °C
SOJO’s 40.5 kV SIS passes:
- Internal arc 31.5 kA 1 s without venting
- Salt-spray 1,000 h ASTM B117 (for coastal topsides)
- Immersion 24 h at 1 m (for flood-prone substations)
- Dielectric test 110 kV BIL at −50 °C (for Arctic mines)
The test matrix effectively replicates a 30-year lifetime in 30 days.
8 Economics: CapEx +8 %, OpEx −60 %
Purchase price is +8 % versus AIS, but life-cycle maths flips the equation:
- No SF₆ top-ups: −USD 120 yr⁻¹
- Halved outage time: −USD 2,400 per intervention
- Smaller civil works: −USD 1,800 per bay
Net present value (8 %, 30 yr) favors SIS by USD 14 k per bay. A 100-bay substation therefore frees USD 1.4 M—capital that can be invested in battery storage or solar augmentation.
9 Conclusion: epoxy is the new copper
Solid insulated switchgear has crossed the triad that matters—technical parity, regulatory mandate and economic upside. In 2025, the question is not whether to specify SIS, but how quickly your supply chain can deliver it blockchain-ready and crane-free.
Future-proof your next substation with Degatech Electric’s solid insulated switchgear—vacuum-interrupted, epoxy-encapsulated, finance-ready—at Degatech Electric Switchgear Products.
