Air pipes can be placed inside cable trays

Air pipes or any mechanical utility piping cannot be installed in cable trays containing electrical cables according to NEC standards.

Regulatory Restrictions

Cable trays are designed specifically to support electrical cables, including power, control, signal, and communication cables. According to the National Electrical Code (NEC) section 300-8, tubes, pipes, or conduits carrying water, air, gas, drainage, or steam are not permitted in cable trays that contain electrical conductors. This restriction exists to prevent potential hazards such as electrical shorts, fire, or damage to cables from leaks, vibration, or heat from the pipes.

Safety and Separation Considerations

Even if air pipes are routed near cable trays, adequate separation must be maintained to avoid interference or damage. Improper spacing can lead to: Heat transfer from pipes affecting cable insulationVibration from air pipes causing mechanical stress on cablesRisk of contamination if pipes leak, potentially causing short circuits or corrosionDifficulty in maintenance and inspection due to cramped spacing The required safety distance depends on the type of cables, the pipe material, and operating conditions, but maintaining a clear separation is essential for both electrical and mechanical system integrity.

Best Practices

Use separate supports: Air pipes should be supported independently from cable trays to avoid mechanical stress on cables. Follow manufacturer and NEC guidelines: Cable trays must be installed according to NEC 392, including proper support spacing, fill limits, and grounding requirements. Avoid shared trays: Do not attempt to combine electrical cables and air pipes in the same tray, even if the tray is large enough.

Consider alternative routing: Use dedicated pipe supports or hangers parallel to cable trays to maintain organized and safe installations.

Summary

Installing air pipes on or inside cable trays with electrical cables is not allowed under NEC regulations. The safest approach is to route air pipes separately, maintain proper clearance, and follow cable tray installation standards to ensure long-term safety, compliance, and system reliability.