Which sub-division does the cable tray belong to

Cable trays are classified under electrical wiring methods and can be installed in specific hazardous sub-divisions depending on the cable type and NEC requirements.

Sub-

Division Classification

Cable trays themselves are considered a wiring support system rather than a cable type, but their use is regulated according to the National Electrical Code (NEC). The classification depends on the hazardous location and the type of cable installed within the tray: Class I, Division 1: Cable trays can be used with Type MC or MI cables that are listed for Division 1 locations. These trays are suitable for industrial areas with flammable gases or vapors where only qualified personnel maintain the installation (NEC 1996, Section 501-4).

Class I, Division 2: Cable trays may contain Type ITC (Instrumentation Tray Cable) or other approved cables without spacing or single-layer restrictions.

Class I

I, Division 1: For combustible dust locations, cable trays can carry Type MC cables listed for Class II, Division 1, with no spacing restrictions.

Class I

I, Division 2: Cable trays can include Type ITC cables without spacing or single-layer requirements (NEC Sections 502-4, 503-3, 504-20) The acceptability of a cable tray system in any hazardous location depends on the cable type installed and compliance with NEC Article 318, which governs ampacity, grounding, fill, spacing, and segregation of cable types.

General Use

Outside hazardous locations, cable trays are used in industrial and commercial installations to support power, control, and communication cables. They provide a flexible, organized, and accessible pathway for cables, with types including ladder, perforated, solid-bottom, and ventilated trays. The choice of tray type and material depends on environmental conditions, cable load, and installation requirements.

Key Takeaway

Cable trays belong to the wiring support system sub-division and their classification in hazardous areas is determined by the NEC division and cable type. Proper selection ensures compliance, safety, and protection of electrical installations in both standard and classified environments.