| 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 Press Click Here to order your Copy.