TABLE - 53
RATING FACTORS FOR VARIATION IN AMBIENT TEMPERATURE FOR CABLES LAID IN AIR (FOR INSTALLATION IN AIR ONLY)
Ambient temperature ° C 25
30
35
40
45
50
55
PVC insulated cables
1.49
1˙.40
1.31
1.22
1.11
1.00
0.86
XLPE insulated cables
1.28
1.23
1.18
1.13
1.06
1.00
0.94
TABLE - 54
RATING FACTORS FOR VARIATION IN AMBIENT TEMPERATURE FOR CABLES LAID DIRECT IN GROUND OR IN DUCTS (FOR INSTALLATION IN GROUND & DUCTS ONLY)
Ground temperature ° C 15
20
25
30
35
40
45
PVC insulated cables
1.25
1.19
1.12
1.06
1.00
0.92
0.85
XLPE insulated cables
1.16
1.13
1.08
1.03
1.00
0.95
0.90
TABLE - 55
RATING FACTORS FOR DEPTH OF LAYING FOR CABLES LAID DIRECT IN GROUND OR IN DUCTS (FOR INSTALLATION IN GROUND & DUCTS ONLY)
Cables Laid Direct in Ground
Cables Laid in Ducts
"Depth of Laying
70 mm² to 300mm2
Upto 50mm2
Above 300 mm2 Single Core
Multicore
Metre
0.75
0.975
0.965
0.947
0.957
0.982
0.8
0.970
0.960
0.940
0.950
0.980
1.0
0.950
0.930
0.920
0.930
0.960
1.25
0.940
0.920
0.890
0.910
0.950
1.5
0.930
0.900
0.870
0.890
0.940
1.75
0.920
0.890
0.860
0.880
0.940
2.0
0.910
0.880
0.850
0.870
0.930
2.5
0.900
0.870
0.840
0.860
0.920
3 or more
0.890
0.850
0.820
0.850
0.910
46 MKK XXS002-02/01-12-2014
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