Armor for Cables Installed in Cable Trays

Armored cables in cable trays provide mechanical protection, environmental resistance, and compliance with safety standards, with steel wire, steel tape, and aluminum armor being the most common options.Purpose of Cable Armor in TraysCable armor is a metal layer wrapped around the exterior of a cable to protect it from mechanical damage, crushing, abrasion, rodent attacks, and environmental hazards . In cable trays, armor ensures that cables maintain their integrity when exposed to potential impacts, vibration, or accidental contact with other equipment . It also enhances fire resistance and provides safer handling for maintenance personnel.Common Types of ArmorSteel Wire Armor (SWA)Provides excellent tensile strength, crush resistance, and impact protection.Suitable for vertical tray runs, high-rise risers, or areas with potential tension.Offers strong rodent protection and is ideal for harsh industrial environments .Pros: High mechanical protection, versatile applications.Cons: Heavier, less flexible, more difficult to install.Steel Tape Armor (STA)Helically or longitudinally wrapped steel tape resists radial compression and provides moderate rodent protection.Suitable for horizontal tray installations and areas with light mechanical stress.Pros: Moderate cost, easier installation than SWA, good crush resistance.Cons: Weaker tensile strength, not ideal for vertical drops .Aluminum ArmorLightweight, corrosion-resistant, and electrically conductive.Often used in lightweight or outdoor tray applications where corrosion is a concern.Pros: Lighter than steel, good EMI shielding in low-current applications.Cons: Requires thicker layers to match steel's crush resistance .Non-Magnetic ArmorMade from stainless steel, aluminum alloy, or non-metallic materials.Used in specialized applications where magnetic interference must be minimized .Installation Considerations in Cable TraysBending Radius: Avoid exceeding the cable's minimum bending radius to prevent internal conductor stress .Support: Use proper tray supports and cleats to prevent sagging, especially for heavy SWA cables .Grounding: Ensure metallic armor is properly grounded to maintain safety and reduce electrical hazards .Protection from Sharp Edges: Use grommets or edge protection where cables pass through tray joints or cutouts .Compliance: Verify adherence to local electrical codes (IEC, NEC, GB/T) for armored tray cable installations .SummaryFor cable tray installations, the choice of armor depends on mechanical stress, environmental exposure, and installation orientation. Steel wire armor is preferred for vertical or high-stress runs, steel tape armor for horizontal or moderate stress areas, and aluminum or non-magnetic armor for lightweight or specialized applications. Proper installation, grounding, and support are essential to ensure the armor performs its protective function and extends cable service life .