Running unarmoured YY control cables (300/500V) together with 0.6/1 kV power cables in the same unpartitioned cable tray is not recommended and violates standard electrical installation codes such as IEC 60364-5-52 [1]and BS 7671 [2]. Unarmoured YY cables lack metallic shielding or armor to block Electromagnetic Interference (EMI) from high-current power conductors. Close proximity induces harmonic noise and voltage spikes into low-voltage control circuits, risking PLC data corruption, sensor malfunction, and safety hazards during insulation breakdown.
Electromagnetic Interference (EMI) and Signal Integrity Risks
Unarmoured YY control cables consist of multiple annealed copper conductors insulated and sheathed in Polyvinyl Chloride (PVC) without a copper braid screen or galvanized steel wire armor.
- Inductive Coupling: When 0.6/1 kV power cables carry heavy load currents, they generate alternating magnetic fields that induce voltages into parallel unshielded control loops.
- Signal Corruption: Sensitive analog signals (4-20mA, RTD, thermocouple) and digital logic inputs within the YY cable experience severe jitter, false triggering, or complete communication failure.
- Transient Spikes: Switching surges or fault currents on the power cable can induce high transient voltages, potentially destroying connected electronic control cards and automation hardware.
Technical Comparison Matrix
| Technical Parameter | YY Control Cable (Unarmoured) | 0.6/1 kV Power Cable (XLPE/PVC) | Co-Tray Compatibility & Risk |
| Rated Voltage | 300/500V | 0.6/1 kV (600/1000V) | High Voltage Gradient: Direct mixing risks insulation puncturing under fault conditions. |
| Mechanical Protection | Basic PVC Sheath (No Armor) | PVC or Galvanized Steel Wire/Tape Armor | Vulnerability: YY lacks impact resistance against heavy power cables. |
| Electromagnetic Shielding | None (Unshielded Multi-Core) | None to Metallic Armor [3] | High EMI Risk: YY acts as an antenna for power cable harmonic noise. |
| Applicable Standards | VDE 0285, EN 50525 | IEC 60502-1 [3], BS 5467 | Segregation Required: Standards mandate physical separation or metallic barriers. |
Recommended Engineering Solutions
If system layout constraints require running control and power lines along the same physical path, adopt these engineering workarounds:
- Upgrade Control Cabling: Replace unarmoured YY cable with CY control cable (copper braided screen for EMI protection) or SY control cable (galvanized steel wire armored for mechanical and partial screening protection).
- Install Metallic Dividers: Use heavy-duty, solidly grounded steel or aluminum cable tray separators to create isolated compartments.
- Route in Separate Conduits: Run the unarmoured YY control cable inside a separate metallic conduit (e.g., rigid steel conduit), which provides both mechanical protection and high-attenuation EMI shielding.
References
[1] Wikipedia.IEC 60364[EB/OL]. 2026-04-02.
[2] Wikipedia. BS 7671[EB/OL]. 2026-04-02.
[3] Wikipedia. Armoured cable[EB/OL]. 2026-04-02.