Table 5.8 - Values of k for protective conductors
Nature of protective conductor
Initial temp.
(C)
Final temp
(C)
Conductor
material
K
p.v.c. insulated, not in cable
or bunched
30
160
Copper
143
-
30
160
Aluminium
95
-
30
160
Steel
52
-
p.v.c. insulated, in cable
or bunched
70
160
Copper
115
-
70
160
Aluminium
76
-
Steel conduit or trunking
50
160
Steel
47
-
Bare conductor
30
200
Copper
159
-
30
200
Aluminium
105
-
30
200
Steel
58

Extracted from The Electricians Guide Fifth Edition
by John Whitfield

Published by EPA Press
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