Location of electrical cable trays in the stairwell

Electrical cable trays in stairwells should be installed along walls or ceilings, maintaining clearances for safety, accessibility, and future maintenance.

Placement and Routing

Cable trays in stairwells are typically mounted along the side walls or under the ceiling to avoid obstructing pedestrian traffic and to comply with safety regulations . Vertical runs should follow the stairwell's structural lines, ensuring that trays do not interfere with handrails, lighting, or fire safety equipment. Horizontal and vertical routes must be clearly marked and coordinated with other building services to prevent clashes .

Support and Clearance

• Supports: Use hanging rods or brackets to secure trays to walls or ceilings. Rods should be at least 8mm in diameter for stability .
• Clearance: Maintain sufficient space for cable pulling, inspection, and maintenance. Vertical spacing from the floor or stair treads should be at least 150mm to prevent obstruction .
• Separation: Power and signal cables should be separated by at least 0.5 meters to minimize electromagnetic interference, or less if shielded .

Tray Type Selection

• Ladder trays are preferred for large power cables due to ventilation and ease of cable management .
• Ventilated trough trays are suitable for smaller control or instrumentation cables that may sag between rungs .
• Material considerations: In high-moisture or corrosive environments, fiberglass-reinforced plastic (FRP) trays provide corrosion resistance and electrical safety .

Safety and Compliance

• Ensure all installations comply with local electrical codes and building regulations.
• Maintain unobstructed egress paths in the stairwell.
• Inspect materials and installation according to approved shop drawings and method statements before energizing the system .

Maintenance Considerations

• Trays should allow easy access for future cable additions or replacements.
• Avoid routing trays in a way that requires technicians to work in unsafe positions on stairs.
• Clearly label trays and cables for identification and troubleshooting. By following these guidelines, cable trays in stairwells can be installed safely, efficiently, and in a manner that facilitates future maintenance and compliance with electrical standards .