| Installation Method | Heat Dissipation Efficiency | Typical Derating | |---------------------|-----------------------------|------------------| | Free air (clipped to wall) | Excellent | Reference rating | | Cable tray (single layer) | Good | Slight reduction | | Buried directly in soil | Moderate (soil thermal resistivity) | Significant reduction | | Conduit (air-filled) | Poor (trapped air) | Heavy reduction | | Cable bundle / trunking | Very poor (mutual heating) | Severe reduction |
: Always consult manufacturer data sheets and national wiring regulations, and perform on-site verification of ambient temperature and installation configuration before finalizing cable ratings. factors affecting cable rating