Wholesale Cable Tray With Cover Ladder Type Manufacturers & Supplier

Installing a solid flush cover limits natural convective air currents generated by current-carrying conductors. In accordance with NEC (NFPA 70) Section 392.80 and IEC 60364-5-52, when multiconductor power cables or single conductors are installed in covered ladder trays without ventilation openings, an ampacity derating factor between 0.85 and 0.90 must be applied depending on conductor layering and cross-sectional fill ratios. To eliminate ampacity derating while preserving falling-object and UV shielding, Qiongkai recommends utilizing peaked raised louvred covers with 25mm to 50mm standoff clips, facilitating continuous chimney-effect ventilation.

Pre-galvanized (mill-galvanized, GI) sheet is coated prior to slitting and stamping, yielding a typical zinc layer thickness of 12 to 20 micrometers (Z180 to Z275). While highly cost-effective for climate-controlled indoor buildings, exposed cut edges rely solely on sacrificial cathodic protection. In contrast, batch Hot-Dip Galvanizing (HDG) per ASTM A123 / ISO 1461 occurs after full fabrication, completely immersing all cut edges, perforations, and weld zones into molten zinc. This process yields an 86 to 120 micrometer thick metallurgical zinc-iron alloy barrier. In standard outdoor industrial environments (ISO 12944 C3/C4), HDG provides 30 to 50+ years of maintenance-free service life, compared to less than 3 to 5 years for pre-galvanized steel.

While AISI 316L stainless steel provides outstanding mechanical yield strength and resistance to marine salts, it remains vulnerable to localized stress corrosion cracking (SCC) and pitting in stagnant chlorine environments at temperatures exceeding 60°C. Pultruded Fiber-Reinforced Polymer (FRP/GRP) using premium vinyl ester resins is chemically inert to wet hydrochloric acid, sulfuric acid vapors, bleach solutions, and aggressive coastal marine spray. Furthermore, FRP is non-conductive, eliminating the necessity for costly equipotential bonding jumpers, and weighs approximately 40% less than equivalent steel sections, drastically reducing pipe rack dead loads.

Standard flat covers held by light friction clips are vulnerable to aerodynamic detachment during severe windstorms. For exterior installations, Qiongkai engineers specify peaked covers with heavy-duty wedge-lock clamps or wrap-around stainless steel 316 retaining straps spaced every 900mm to 1200mm. The peaked geometry sheds rainwater, snow accumulation, and airborne dust while creating aerodynamic downward vectors that counteract suction lift. Our assemblies are physically tested to withstand wind speeds up to 250 km/h (155 mph) in compliance with ASCE 7-16 structural load criteria.

Yes. With 12 automated roll-forming lines and high-precision CNC punching, we regularly manufacture non-standard side-rail depths (including 75mm, 100mm, 125mm, 150mm, and 200mm) and tray widths from 100mm up to 1200mm. Rung spacing can be configured at 150mm (6"), 225mm (9"), 300mm (12"), or 450mm (18") intervals to match specific cable minimum bending radii and clamping requirements. Additionally, our factory fabricates matching horizontal bends, vertical inside/outside elbows, tees, and cross reducers with customizable 300mm, 600mm, or 900mm turning radii.

We support Incoterms 2020 including FOB Shanghai, CIF, and DDP to major worldwide ports. Every order is provided with complete Mill Test Certificates (MTC) conforming to EN 10204 Type 3.1, detailing base metal chemical analysis, tensile and yield strength, and zinc coating thickness measurements. Factory Acceptance Testing (FAT) is routinely coordinated with third-party inspection agencies including SGS, Bureau Veritas (BV), Intertek, and TÜV Rheinland prior to container loading at our Shanghai export staging hub.