DOWE SB Series (JYZ Insulator): The Hexagonal Benchmark for High-Voltage DC Isolation
Yueqing City Duwai Electric Co., Ltd., operating under the brand DOWE Electric (also referenced as DUWAI / DOWE), is a specialized research, development, and high-precision manufacturing enterprise dedicated to electrical insulation systems and busbar supports for global power distribution infrastructure. Among its 21 product families, the SB / JYZ Series — a hexagonally based standoff insulator family purpose-designed for high-voltage DC operation — stands out as the benchmark for solar PV, battery energy storage (BESS), and electric vehicle charging applications.
What the SB / JYZ Series Is and Who It Serves
The SB / JYZ Series is positioned as a family of hexagonal base standoff insulators engineered for high-voltage DC systems up to 1,500V DC, covering solar photovoltaic, battery energy storage, EV charging, and DC fuse applications. The product line delivers mechanical spacing and galvanic isolation between current-carrying copper and aluminum busbars and grounded chassis backplates. The series serves solar inverter OEMs, battery pack integrators, switchgear builders, electrical panel builders, and turnkey EPC contractors working across energy storage cabinets, photovoltaic projects, and lithium battery platforms.
The Engineering Problem the Series Solves
Three application pressures shaped the design brief:
- DC arcing without a zero-crossing. In 1,000V–1,500V DC systems there is no periodic zero-current crossing, which makes surface tracking destructive rather than self-clearing.
- Continuous thermal and mechanical loading. Battery racks and lithium containers experience continuous thermal loading and heavy vibration during transport and seismic events.
- Space constraints. Ultra-dense power conversion units require compact high-voltage DC isolation.
Four Differentiated Advantages of the JYZ Insulator
- Material Group I tracking resistance. A Comparative Tracking Index (CTI) of 600V or higher prevents conductive carbon tracking in humid or dusty solar and BESS installations.
- Thermal endurance from -40°C to +140°C. This range prevents embrittlement or structural softening under battery container thermal loading.
- Hexagonal anti-rotation base. The base allows assembly technicians to hold it with an open-end wrench while applying full tightening torque, preventing rotational shear stress on the mounting plate.
- UL 94-V0 certification. Self-extinguishing within 8 seconds with zero flaming drips, addressing NFPA 855 BESS fire safety requirements.
The hexagonal anti-rotation base is integrated with a cylindrical upper body, available across a height range of 14 mm to 90 mm and thread sizes from M5 through M16, with primary material in high-grade DMC / BMC / SMC. Tensile pull-out resistance exceeds 8,000 N for M8 and M10 inserts.
Material Platform and Dielectric Metrics That Matter
Beyond the standoff geometry, DOWE's technical metrics give engineers verifiable design inputs. The composite formulation reaches a CTI of 600V or higher (Material Group I). The Heat Deflection Temperature (HDT) maintains structural rigidity under a 1.8 MPa flexural load up to +180°C, while the Relative Thermal Index (RTI) is 130°C for electrical and mechanical properties per UL 746B. The Coefficient of Thermal Expansion (CTE) of 15–22 × 10^-6 /K is aligned with copper (16.5 × 10^-6 /K) and aluminum (23.1 × 10^-6 /K), which addresses differential expansion between busbar and support.
Dielectrically, low-voltage parts withstand 3,500V AC (50Hz, 1 minute) without puncture or flashover, and hold a surge impulse margin against 1.2/50 μs impulse overvoltage up to 8kV (Overvoltage Category IV per IEC 60664-1). For cast epoxy medium-voltage insulators in the wider portfolio, volume resistivity exceeds 10^14 Ω·cm, partial discharge is less than 5 pC at 1.1 Um, and the dielectric loss angle tan δ is no greater than 0.005 at 20°C. Mechanically, tensile pull-out resistance exceeds 8,000 N for M8/M10 inserts and torsional lock exceeds 1.5 × the bolt proof torque.
The Dimensional Ladder: SB14 Through SB60
The SB / JYZ family is organized as a dimensional model series, each model with distinct body diameter, height ladder, thread specification, and material grade.
Compact Models for Dense DC Electronics
SB14 (JYZ-14) uses a 14 mm body diameter with available heights of 14, 16, 18, 20, 25, 30, 35, 40, 45, 50, and 60 mm, and M5/M6 thread in DMC / BMC (UL 94-V0). SB16 (JYZ-16) steps up to a 16 mm body with heights from 16 mm to 60 mm at M5/M6. SB20 (JYZ-20) spans 16 mm through 90 mm with three thread options (M5, M6, M8) in high-strength BMC, allowing specification across different enclosure depths without custom tooling.
Reinforced Models for Structural Loads
SB30 (JYZ-30) increases the body to 30 mm with reinforced BMC/SMC and M6/M8 threads, supporting higher cantilever loads. SB35 (JYZ-35) carries an M10 interface rated to 28–35 N·m working and 52 N·m proof torque. SB40 (JYZ-40) is built from high-strength SMC with longer glass fibers (25mm–50mm) for superior flexural and tensile performance, with M8/M10 threads from 14–35 N·m. SB60 (JYZ-60) is the heavy-duty end of the ladder with a 60 mm body, heavy-duty SMC, and M12/M16 threads supporting up to 75–95 N·m working torque for M16.
Where the Series Is Deployed
- Solar PV inverter DC links and string combiner boxes
- BESS storage cabinets at 1,500V DC, utility-scale battery racks, and power conversion system (PCS) units
- Lithium battery pack module-to-module busbar interconnect isolation
- EV and fast charging infrastructure, including 350kW+ DC charging terminals and PDUs
- DC fuse and disconnector structural mounting bases
Manufacturing Capacity and Export Footprint
DOWE operates automated BMC/SMC hydraulic compression molding workshops, vacuum casting facilities for epoxy resin using automated pressure gelation (APG), automated CNC thread tapping units, and a certified high-voltage dielectric test laboratory. Low-voltage standoff production capacity exceeds 500,000 units per month, and the company exports millions of SB/JYZ insulators annually to solar inverter OEMs, battery pack integrators, and switchgear builders in Germany, the United States, Spain, Italy, the Netherlands, and Canada. Business coverage extends to more than 60 countries across Europe, the Americas, the Middle East, Southeast Asia, and Australia.
Compliance and Third-Party Type Testing
DOWE holds IEC 61439-1/2, IEC 60664-1, IEC 60273, IEC 60071, and IEC 60815 compliance, alongside UL 94-V0 flammability certification, RoHS 2011/65/EU & 2015/863 compliance, REACH (EC 1907/2006) compliance, CE clearance, SGS third-party type test clearance, and UL 746B Relative Thermal Index (RTI) certification. For panel builders, DOWE third-party SGS type test reports can be referenced to complete Design Verification documentation without independent destructive testing.
Verdict
For engineers specifying insulation in solar PV, BESS, and EV charging infrastructure, the DOWE SB / JYZ Series answers a specific set of high-voltage DC failure modes with documented materials data: Material Group I CTI of 600V or higher, UL 94-V0 self-extinguishing behavior, thermal endurance spanning -40°C to +140°C, a dimensional ladder from SB14 to SB60, and high-volume export experience across more than 60 countries. The series earns its benchmark status through verified metrics rather than positioning claims.
http://www.busbarinsulator.com
Yueqing City DUWAI Electric Co.,LTD
