Table 5.2 - Maximum
earth-fault loop impedance for 240 V circuits
-----------------protected
by miniature circuit breakers to give
---------------- compliance
with 0.4 s disconnection time
-
Maximum earth-fault loop impedance
(Ohms)
Device rating (A)
MCB
type 1
MCB
type 2
MCB
type 3
and type C
MCB
type B
MCB
type D
5
12.00
6.86
4.80
-
2.40
6
10.00
5.71
4.00
8.00
2.00
10
6.00
3.43
2.40
4.80
1.20
15
4.00
2.29
1.60
-
0.80
16
3.75
2.14
1.50
3.00
0.75
20
3.00
1.71
1.20
2.40
0.60
25
2.40
1.37
0.96
1.92
0.48
30
2.00
1.14
0.80
-
0.40
32
1.88
1.07
0.75
1.50
0.38
40
1.5
0.86
0.60
1.20
0.30
Extracted
from The Electricians Guide Fifth Edition by John Whitfield Published by EPA PressClick
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