Overhead Cable Trays

In data centers that use overhead pathways, 150 mm (6 in) minimum access headroom shall be provided from the top of the pathway to the obstruction located above such as another pathway or the ceiling. This clearance requirement does not apply where cable trays cross each other or cross beams, pipes or other building structures.

Typical cable tray types for overhead cable installation include wire basket cable tray, ladder type, or center spine cable tray. Adjacent sections of metallic cable tray shall be bonded together and grounded per manufacturers’ guidelines, /NECA/BICSI 607, other applicable standards (e.g., TIA-607-B), and the local authority and shall be listed or classified by an NRTL for this purpose.

The metallic cable tray system shall be bonded to the data center common bonding network.

When they are supported from above; overhead cable ladders or trays (if used) shall be suspended from the structure above utilizing M12 (0.5 in) or greater threaded rods as required for structural support.

The cable trays or ladders may be supported by an overhead support structure using support pillars or a suspended frame designed to support the load of the cable tray and cables.

If used for seismic bracing, ladder racks and cable tray shall be continuous wall to wall to form a brace for the equipment.

Cable tray shall not be routed directly below fire suppression or sprinkler systems.

In data centers that use overhead pathways, 300 mm (12 in) minimum access headroom should be provided from the top of the pathway to the obstruction located above such as another pathway or the ceiling.