Factors Affecting Cable Rating -

| 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 |

Understanding the is essential for any electrical installation, as a cable's current-carrying capacity (ampacity) is not a fixed number. Instead, it is highly dependent on how and where the cable is installed. factors affecting cable rating