Cable tray construction must comply with IEC 61537 internationally and NEC Article 392 in the U.S., covering material, load, grounding, and installation safety requirements.

Key Standards and Guidelines

IEC 61537 is the international standard for metal cable tray systems, specifying construction, testing, and performance requirements. It applies to trays made of steel, stainless steel, aluminum, or other metallic materials, ensuring they can support cable loads, resist environmental factors, and maintain electrical continuity for grounding purposes . Compliance ensures safety, compatibility, and long-term reliability. NEC Article 392 governs cable tray systems in the U.S., defining them as support structures rather than enclosed raceways. It specifies acceptable cable types (e.g., Type TC or metal-armored Type MC), installation practices, and optional covers for protection in high-traffic or outdoor areas . Adherence prevents electrical hazards and ensures structural integrity.

Material and Corrosion Considerations

Cable trays can be manufactured from steel, stainless steel, aluminum, or fiberglass-reinforced plastics, with finishes chosen based on environmental exposure . Stainless steel (e.g., AISI 316L) offers high corrosion resistance, while aluminum provides lightweight durability and natural oxide protection. Galvanized steel is commonly used for cost-effective corrosion protection. Material selection must consider mechanical strength, corrosion resistance, and environmental conditions.

Mechanical and Installation Requirements

• Load Capacity: Trays must support the weight of cables and environmental loads without excessive sagging. IEC 61537 specifies testing for deflection and yield strength at various spans .
• Spacing and Bend Radius: Rung spacing is typically 150–230 mm, and minimum bend radii must be maintained to prevent cable damage .
• Supports: Trays should be installed on supports designed for the system, avoiding use as walkways or ladders .
• Electrical Continuity: Trays used for grounding must maintain resistance below 0.1 ohms across joints to safely carry fault currents .

Safety and Compliance

• Only competent personnel familiar with electrical installation practices should perform installation .
• Covers are recommended in areas with potential mechanical impact or outdoor exposure .
• Systems should be installed using components designed and tested together to ensure safe operation .
• Compliance with CE marking, UL, or other national certifications may be required depending on the region .

Summary

Construction regulations for cable trays focus on material selection, mechanical strength, proper installation, grounding, and environmental protection. Following IEC 61537 and NEC Article 392 ensures that cable trays safely support electrical and communication cables, prevent hazards, and maintain long-term system reliability . Proper adherence to these standards is essential for both safety and regulatory compliance.