Cables are run in cable trays and then concealed

Cables running through cable trays are generally not considered concealed, as cable trays are open support systems rather than enclosed raceways.

Explanation

Cable trays are mechanical support systems designed to hold and organize electrical, communication, and data cables. They are typically open structures, such as ladder-type, perforated, or wire mesh trays, which allow easy access for installation, inspection, and maintenance. Because of their open nature, cables installed in trays are exposed and accessible, unlike concealed wiring that is hidden within walls, floors, ceilings, or enclosed trunking.

Regulatory Context

According to the National Electrical Code (NEC) and related standards, a raceway is defined as an enclosed channel for holding wires or cables. Cable trays do not meet this definition and are explicitly classified as support systems rather than raceways. Consequently, cables in trays are not treated as concealed for compliance purposes.

This distinction affects requirements for mechanical protection, fire-stopping, and inspection access.

Practical Considerations

While cables in trays are not concealed, they still require protection from mechanical damage, especially when passing through metallic structures or sharp edges. Standards such as AS/NZS 3000 specify that cables must be bushed or protected to prevent abrasion or insulation damage. Cable trays provide structural support but do not inherently conceal or fully protect cables from external hazards.

Summary

Cables in cable trays are exposed and accessible, not hidden within building structures. Cable trays are support systems, not raceways, so wiring in them is not considered concealed. Mechanical protection may still be required where cables pass through sharp edges or penetrations.

Concealed wiring typically refers to cables embedded in walls, floors, ceilings, or enclosed trunking, which is distinct from tray installations. In conclusion, if your installation uses cable trays, the cables are not classified as concealed, and relevant wiring regulations for concealed cables do not directly apply.