Selection Guide for Insulating Fasteners in New Energy and Telecom Equipment
Selection Guide for Insulating Fasteners in New Energy and Telecom Equipment
The rapid expansion of solar, energy storage, and 5G telecom industries has driven increasingly stringent electrical safety requirements. Insulating fasteners, as critical components preventing electrical leakage, short circuits, and galvanic corrosion, directly impact equipment reliability and certification compliance. This article presents a comprehensive selection methodology for insulating fasteners across typical new energy and telecom deployment scenarios.
Application Scenarios and Core Requirements
PV inverters contain DC 1500V high-voltage circuits where insulating fasteners secure IGBT modules, capacitor busbars, and safety barriers, requiring volume resistivity ≥10^12 Ω·cm and CTI (Comparative Tracking Index) ≥600V. In energy storage battery cabinets, insulating screws fasten inter-module busbars and BMS sampling wiring, requiring UL94 V-0 flammability and resistance to -40°C to 85°C thermal cycling. In 5G AAU (Active Antenna Unit) equipment, insulating fasteners provide isolation between RF boards and metal enclosures, demanding low dielectric loss (tanδ<0.01) to avoid signal attenuation, plus compatibility with IP65 weather-sealing designs.
Material Selection Decision Matrix
For standard scenarios, pa66-GF30% (glass-fiber reinforced nylon) is preferred, balancing insulation and mechanical strength at optimal cost. For high-temperature environments (>120°C) or high-CTI requirements, PA46 or PPS are recommended—PPS offers HDT up to 260°C and CTI>600V. For corrosive or outdoor weathering applications, pvdf provides excellent UV and ozone resistance. For ultra-high-frequency RF scenarios (mmWave), peek offers a stable dielectric constant around 3.2 with minimal high-frequency loss. For connection points requiring both structural strength and insulation, a hybrid approach of "metal screw + insulating sleeve/washer" is effective, with sleeves typically made of pa66 or PET at 0.5–1.0mm wall thickness.
Torque Specifications and Certification Requirements
Installation torque for insulating fasteners must be strictly controlled: recommended torque for PA66 screws is 0.3–0.5 N·m for M3, 0.6–0.9 N·m for M4, 1.0–1.5 N·m for M5, and 1.8–2.5 N·m for M6. Exceeding these limits risks thread stripping or head fracture. For exported products, EU markets require RoHS 2.0 (2011/65/EU) and REACH SVHC compliance; US markets require UL94 flammability certification and compliance with IEC 60998/UL 1977 connector standards. PV equipment must meet IEC 62548 (PV array safety) and UL 1741 (inverter standard); energy storage systems must satisfy UL 9540A thermal runaway testing requirements for non-metallic materials. Buyers should request Certificates of Analysis (COA), SGS test reports, and UL Yellow Card numbers from suppliers.