Can low-voltage and low-voltage power supplies share the same cable tray

Low-voltage and low-voltage power supplies can share the same cable tray only if proper separation, insulation, or shielding measures are implemented to prevent interference and ensure safety. Key Considerations1. Regulatory Requirements According to the National Electrical Code (NEC) Article 300.

3(C)(1), mixing power and low-voltage cables in the same tray is generally prohibited unless specific separation or shielding requirements are met. International standards like IEC 60364-5-52 also recommend physical separation or shielding to prevent electromagnetic interference (EMI) between circuits. 2.

Electromagnetic Interference (EMI) and Signal Integrity Power cables generate magnetic fields that can induce noise in nearby low-voltage circuits, potentially causing signal degradation, latency, or erratic operation. Even low-voltage power supplies can create interference if routed too closely without barriers. 3.

Physical Separation and Barriers If sharing a tray is unavoidable, best practices include: Divider brackets or compartmentalized trays to physically separate circuits. Minimum separation distances, often recommended at 12–16 inches for parallel runs, or at least 30 cm in some guidelines. Crossing at 90-degree angles when low-voltage and power cables must intersect to minimize EMI.

4. Insulation and Voltage Rating All cables in a shared tray should be rated for the highest voltage present. Low-voltage cables must have insulation sufficient to withstand potential induced voltages from adjacent power circuits, typically up to 600V.

5. Shielding and Grounding Using shielded low-voltage cables with proper grounding can reduce EMI, but shielding does not replace the need for physical separation mandated by NEC or IEC standards. 6.

Inspection and Compliance Improper mixing of circuits is a common inspection failure.

Following NE

C 725. 136, 760. 53/760.

136, and 805 routing rules ensures compliance and reduces rework. Always consult the Authority Having Jurisdiction (AHJ) for site-specific requirements.

Summary

While it is technically possible for low-voltage and low-voltage power supplies to share a cable tray, it is strongly recommended to implement physical separation, use divider brackets, or compartmentalized trays, ensure proper insulation, and consider shielding to prevent EMI and maintain safety. Compliance with NEC, IEC, and project-specific standards is essential to avoid hazards and ensure reliable system performance.