Page 920 - Industrial Power Engineering and Applications Handbook

281870 Industrial Power Engineering and Applications Handbook

i P,4

/ I / /

1 1.2 1.4 1.6 1.8 0
I
S-a-
a+b
Figure 28.7 Space factor for rectangular conductors (Courtesy: The Copper Development Association)
Table 28.3 Derating factors on account of higher ambient temperature or restricted temperature rise

(a) Operating temperature 85'12 (b) Operating ternlieratwe 90°C
_-
Ambient Permissible bur Deruting factor Ambient Permissible bur Derating factor
temperarure "C temperarure rise "C temperature "C temperature rise "C
30 55 I .05 I 35 55 1.05
35 50 1 .o I 40 50 I .0
40 45 0.945 45 45 0.945
45 40 0.88 50 40 0.88
50 35 0.815 55 35 0.815
55 30 0.75 60 30 0.75
Notes
I These data are drawn in the shape of a graph in Figure 28.10. 2 Intermediate values can be obtained by interpolation.