TABLE 7
TREFOIL OR FLAT FORAMTION DERATING FACTORS FOR MULTI-CORE CABLES LAID DIRECT IN GROUND.
NUMBER OF CIRCUITS
TREFOIL FORMATION
FLAT FORMATION
TOUCHING
SPACING = 0.15 M
SPACING = 0.30 M
NR
TREFOIL
FLAT
TREFOIL
FLAT
TREFOIL
FLAT
2
3
4
5
6
081
0.69
0.62
0.58
0.54
0.81
0.70
0.63
0.60
0.56
0.87
0.76
0.72
0.66
0.63
0.87
0.78
0.74
0.70
0.67
0.91
0.82
0.77
0.73
0.70
0.91
0.84
0.81
0.78
0.76

TABLE 8
FLAT FORMATION DIRAECTING FOR FACTORS THREE SINGLE CORE CABLE LAID IN FREE AIR.

Clearance = Cable dimeter (d)

Clearance from the wall ≥ 2cm
Number of troughs
1
2
3
0.92
0.89
0.88
Laid on the Floor
Number of troughs
Laid cables                     1
troughs                          2
(circulation of air           3
is res                              6
0.92
0.87
0.84
0.82
0.89
0.84
0.82
0.80
0.88
0.83
0.81
0.79

Number of troughs

     

                                          1
Laid                                   2
on cable racks                   3
                                          6
1.00
0.97
0.96
0.94
0.97
0.94
0.93
0.91
0.96
0.93
0.92
0.90
Arranged near the wall
0.94
0.91
0.89
Arranged on the wall
0.89
0.86
0.84
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