Cable tray procurement and lightning protection

Effective lightning protection for cable trays involves proper material selection, grounding, surge protection, and compliance with IEC 62305 standards.

Material and Design Considerations

When procuring cable trays, select materials with high conductivity and corrosion resistance, such as stainless steel (AISI 316L) or aluminum alloys, to ensure reliable conduction of lightning currents and long-term durability in harsh environments ( ). Ventilated or solid-bottom trays can be chosen based on the risk of heat buildup and electromagnetic interference, while mesh or ladder-type trays provide flexibility for bonding and grounding connections ( ).

Grounding and Equipotential Bonding

Cable trays must be integrated into the building's earthing system. All metallic trays should be bonded to the main equipotential bonding network to safely conduct lightning currents to the ground ( ). This reduces the risk of side-flashes and ensures that approximately 50% of the lightning energy is safely dissipated into the earth, while the remainder is distributed through the equipotential system ( ).

Surge Protection

To protect sensitive equipment connected to the cable trays, install surge protection devices (SPDs) at key points along the power and data lines.

SP

Ds should be coordinated in stages according to the lightning protection zone concept, from air-termination devices to terminal equipment, ensuring that residual voltage peaks are minimized ( ). Compliance with StandardsEnsure that all cable trays and associated lightning protection components comply with IEC 62305 and relevant national standards. This includes proper sizing of conductors, spacing, and testing for withstand voltages to handle direct and indirect lightning strikes ( ).

Certification from recognized bodies (e.g., UL, VDE) provides assurance of compliance and performance ( ).

Installation Best Practices

Maintain continuous metallic paths without gaps to prevent arcing. Use mechanical fasteners and bonding jumpers to connect tray sections. Avoid routing trays near high-risk areas without additional shielding.

Verify that tray supports and hangers are conductive or properly bonded to the earthing system ( ).

Summary

For safe and reliable cable tray procurement under lightning-prone conditions, focus on material selection, grounding, surge protection, and adherence to IEC 62305 standards. Proper integration into the lightning protection system ensures both personnel safety and protection of electrical and electronic equipment.