Cable trays in the stairwell are covered

Cable trays in stairwells should remain open and accessible; covering them may violate NEC and OSHA regulations and create safety hazards.

Regulatory Considerations

According to NEC Article 392, cable trays are designed as open structures to support electrical conductors while allowing proper ventilation and maintenance access . The code explicitly states that cable trays must remain accessible and should never be permanently enclosed, particularly in areas like stairwells or hoistways, which are considered restricted or high-risk spaces . Covering trays in these locations can violate NEC 392.4 and OSHA 29 CFR 1910.305(a)(3)(ii), which prohibit cable trays in enclosed or inaccessible areas .

Safety Risks

Covering cable trays in stairwells introduces several hazards:

• Overheating: Open trays allow heat dissipation from current-carrying conductors. Covering them can trap heat, increasing the risk of insulation damage or fire .
• Maintenance Access: Covered trays prevent easy inspection, repair, or cable replacement, which is critical for safety and operational reliability .
• Fire Spread: Stairwells are critical egress paths. Enclosing cable trays without proper fire-stopping measures can facilitate fire propagation and compromise evacuation routes .

Proper Installation Practices

If covering is necessary for aesthetic or protection reasons, the following guidelines should be followed:

• Use removable covers that allow inspection and maintenance.
• Ensure adequate ventilation to prevent heat buildup.
• Maintain clearances above and around the tray as required by NEC (at least 12 inches for vertical access) to allow safe work .
• Avoid placing trays in hoistways, stairwells, or other enclosed spaces unless specifically designed and approved for such use .
• For solid-bottom or covered trays, ensure they are rated for the heat load and cable type installed, and follow manufacturer specifications .

Recommendations

• Do not permanently cover cable trays in stairwells; instead, use open or ventilated trays to comply with NEC and OSHA standards.
• If protection is needed, consider wire mesh or ventilated channel trays that provide physical protection while maintaining airflow and accessibility .
• Regularly inspect trays for fill limits, grounding, and separation of high- and low-power cables to prevent overheating and electromagnetic interference . Maintaining open, accessible cable trays in stairwells ensures code compliance, fire safety, and ease of maintenance, reducing the risk of electrical hazards and supporting safe building egress.