Derating factor for thermal resistivity

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Table 29: RATING FACTORS

THERMAL RESISTIVITY OF THE SOIL (FROM 1.2°C.m/W) BURIED DIRECT IN GROUND AND IN UNDERGROUND WIRING ENCLOSURES

Thermal resistivity of soil °C.m/W Multicore cable buried direct Two or three single-core cables buried direct Multicore cable in a wiring enclosure Two single-core cables in a wiring enclosure Three single-core cables in a wiring enclosure
0.8 1.09 1.16 1.03 1.06 1.08
0.9 1.07 1.11 1.02 1.04 1.06
1.0 1.04 1.07 1.02 1.03 1.04
1.2 1.00 1.00 1.00 1.00 1.00
1.5 0.92 0.90 0.95 0.94 0.92
2.0 0.81 0.80 0.88 0.86 0.83
2.5 0.74 0.72 0.83 0.80 0.77
3.0 0.69 0.66 0.78 0.75 0.71


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