Table 5.3 - Maximum impedance of circuit protective
----------------- conductors to allow 5 s disconnection time
----------------- for socket outlets
-
Maximum impedance of circuit protective conductor
Rating (A)
Fuse BS 88
Fuse BS 1361
Fuse BS 3036
MCB type 1
MCB type 2
MCB type 3 & C
MCB type B
MCB type D
5
-
3.25
3.25
2.50
1.43
1.00
-
0.50
6
2.48
-
-
2.08
1.19
0.83
1.67
0.42
10
1.48
-
-
1.25
0.71
0.50
1.00
0.25
15
-
0.96
0.96
0.83
0.48
0.33
-
-
16
0.83
-
-
0.78
0.45
0.31
0.63
0.16
20
0.55
0.55
0.63
0.63
0.36
0.25
0.50
0.12
25
0.43
-
-
-
-
-
-
0.10
30
-
0.36
0.43
0.42
0.24
0.17
-
-
32
0.34
-
-
0.39
0.22
0.16
0.31
0.08
40
0.26
-
-
0.31
0.18
0.13
0.25
0.06
45
-
0.18
0.24
0.28
0.16
0.11
0.22
0.06

Extracted from The Electricians Guide Fifth Edition
by John Whitfield
Published by EPA Press Click Here to order your Copy

Click here for list of abbreviations