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Temperature Correction Factors for Conductor Resistances

CURRENT RATING CORRECTION FACTORS FOR AMBIENT TEMPERATURE

REFERENCE- BS 7671, IEE WIRING REGULATION :

AMBIENT TEMPERATURE PVC INSULATED 70'C HR PVC INSULATED 90'C THERMOSETTING INSULATED 90'C
25 1.03 1.03 1.02
30 1.00 1.00 1.00
35 0.94 0.97 0.96
40 0.87 0.94 0.91
45 0.79 0.91 0.87
50 0.71 0.87 0.82
55 0.61 0.84 0.76
60 0.5 0.8 0.71
65 0.35 0.76 0.65

TABLE FROM ERA 69-30 PART V

XLPE INSULATED CABLES AMBIENT TEMPERATURE 'C LAID DIRECT IN DUCTS INSULATED IN AIR
10 1.03 1.03 1.11
15 1.00 1.00 1.07
20 0.97 0.97 1.04
25 0.93 0.93 1.00
30 0.89 0.89 0.96
35 0.86 0.86 0.92
40 0.82 0.82 0.88
45 0.77 0.77 0.83
50 0.73 0.73 0.78
55 0.68 0.68 0.73
60 0.63 0.63 0.68
65 0.58 0.58 0.62

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