Hebei Shenyi Metal Products Co., Ltd. is one of the leading manufacturers and suppliers of closed cable trunking in China. If you're going to wholesale bulk closed cable trunking made in China, welcome to get free sample from our factory. All customized metal products are with high quality and competitive price.

Structural Features & Material Thickness

The trunking body is formed by cold-rolled steel plates or other high-strength materials, with a smooth inner surface to avoid cable abrasion. Standard thickness options for general applications:

1.0mm, 1.2mm, 1.5mm – suitable for daily industrial and commercial installation.

For large-span installation (e.g., between factory columns) or heavy-load cabling (e.g., multiple high-voltage cables), reinforced thickness options 2.0mm, 2.5mm, 3.0mm are recommended.

These thicker plates provide excellent structural rigidity, resisting deformation even under extreme loads or long-span conditions.

Available Materials & Surface Finishes

Closed cable trunking can be manufactured from a variety of materials and coatings to match specific environmental requirements:

Electro-galvanized (EG)

Provides a uniform, bright surface with basic corrosion resistance for indoor dry environments.

Hot-dip galvanized (HDG)

Thicker zinc coating offers superior anti-corrosion performance, ideal for outdoor, humid, or mildly chemical industrial areas.

Fire-retardant coating

Special intumescent paint or powder coating that delays flame spread; essential for fire-sensitive zones such as escape routes, data centers, or petrochemical plants.

Stainless steel (SS304 / SS316)

Excellent resistance to rust and chemical attack. SS316 is particularly suitable for marine environments or highly corrosive conditions.

Aluminum alloy

Lightweight, naturally corrosion-resistant, and easy to install. Perfect for applications where weight reduction is critical, such as high-rise buildings or mobile structures.

Protective Functions

Due to its fully enclosed design, closed cable trunking provides three major protective benefits:

Dust protection – Prevents accumulation of conductive dust or fine particles that could cause tracking or short circuits, ensuring long-term reliability in workshops, cement plants, or food processing facilities.

EMI shielding – The metal enclosure acts as a Faraday cage, reducing external electromagnetic interference (EMI) to sensitive control and communication cables. This is critical for signal integrity in automation, IT rooms, and medical equipment installations.

Physical cable protection – Shields cables from accidental impacts, rodent bites, and UV radiation (if external cover is added). It also prevents cable sagging or twisting, extending cable service life.

Typical Applications

Closed cable trunking is widely used in:

Industrial plants and warehouses – organizing power and control cables while resisting dust and oil mist.

Commercial buildings – vertical and horizontal cable routing for lighting, HVAC, fire alarms, and security systems.

Data centers and server rooms – protecting sensitive data cables from EMI and dust, with fire-retardant options available.

Utility tunnels and pipe galleries – long-span, corrosion-resistant solutions for high-voltage and communication cables.

Outdoor installations – hot-dip galvanized or stainless steel trunking for bridges, viaducts, and street lighting systems.

Installation Accessories & Considerations

To ensure a robust installation, closed cable trunking systems are complemented by accessories:

Couplers & splice plates – for connecting adjacent sections.

Hangers, wall brackets, or support channels – to secure trunking at required intervals (typically 1.5m to 2m support spacing for standard loads, reduced for heavy loads).

Internal or external elbows, tees, cross pieces, and reducers – for direction changes and branching.

Grounding jumpers – ensure electrical continuity across all metal sections for safety.

Installation tips:

Use proper cutting tools to avoid burrs that may damage cables.

For heavy-load or long-span conditions, double the number of supports or use reinforced brackets.

Always follow local electrical codes and the manufacturer's torque specifications for fasteners.

Quality & Compliance

Quality closed cable trunking is typically manufactured in accordance with international standards such as IEC 61537 (Cable tray systems – requirements for installation and performance) or NEMA VE 1 / CSA C22.2 No. 126.2.

The product should undergo load testing, grounding continuity tests, and corrosion resistance validation. Fire-retardant versions must meet UL 94 V-0 or equivalent flammability ratings.