Electrical shafts and cable trays

Cable trays can be placed in electrical shafts if proper firestopping, layout, and installation standards are followed.Suitability of Electrical Shafts for Cable TraysElectrical shafts are commonly used to route cables vertically between floors in buildings. Installing cable trays in these shafts is acceptable, provided that the design ensures safe support, accessibility for maintenance, and compliance with fire protection requirements . Cable trays in shafts help organize multiple cables, reduce congestion, and facilitate future cable additions or replacements.Firestopping and Safety ConsiderationsWhen cable trays pass through shafts, walls, or slabs, all openings must be sealed with firestopping materials to prevent fire and smoke spread . Key requirements include:Use of fire-rated boards, firestop packs, firestop mastic, or fire-resistant mineral wool around cables and trays.Gap areas between firestop materials and cables should not exceed 1 cm², and packing thickness should meet minimum standards (e.g., 24 cm for certain applications).Waterstops of at least 50 mm at floor or slab penetrations.Installation of fire-support plates at slab penetrations to maintain structural and fire integrity.Ensuring tight, crack-free sealing both internally and externally around metal trunking or trays. These measures ensure that the shaft maintains its fire-resistance rating while allowing cable trays to be installed safely.Installation Best PracticesLayout and positioning should allow for easy installation, inspection, and maintenance .Cable trays should be supported adequately to handle the weight of cables and any additional loads, including short-circuit forces .Ventilated or solid-bottom trays may be selected depending on heat dissipation needs and environmental conditions .Compliance with IEC 61537 or equivalent standards ensures mechanical strength, corrosion resistance, electrical continuity, and fire performance .SummaryCable trays can be installed in electrical shafts, but it is essential to follow firestopping protocols, proper support, and international standards. This ensures safety, accessibility, and long-term reliability of the electrical installation while maintaining the fire-resistance integrity of the shaft. Proper planning and adherence to technical guidelines are critical for a compliant and safe installation .