Code of Practice for the Electricity (Wiring) Regulations - 2009 Edition

Length of
Busbars
(metres)
Table 9(3)
Approximate Prospective Fault Current at
Tap-off Positions of Busbar Rising Mains Installation in
kA (kilo-Amperes)
Rating of Rising Mains
200–300A 400–500A 600–800A 1000–2500A
kA kA kA kA
10 24 26 30 33
13 22 25 30 33
16 21 24 30 33
19 20 23 28 33
22 18 22 28 33
25 18 22 28 33
28 17 21 26 30
31 16 20 26 30
34 15 20 26 30
37 15 19 26 30
40 14 18 24 30
43 13 18 24 30
46 13 17 24 30
49 12 17 24 30
52 12 17 24 28
55 11 16 24 28
58 11 16 22 28
61 11 15 22 28
64 10 15 22 28
67 10 15 22 28
70 10 14 22 28
73 9 14 22 28
76 9 14 20 26
79 9 13 20 26
82 9 13 20 26
85 8 13 20 26
88 8 13 20 26
91 8 12 20 26
94 8 12 20 26
97 7 12 20 26
(Note: The information and values given in this Table are intended for
general guidance only as the prospective fault current will vary for
different kinds of busbars)
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