For instance in a TN system with nominal mains voltage Uo = 230 V
protected by gG fuses the Ia and max Zs values could be:
Using the current ranges on models 4118A can be also tested the
Prospective Fault current.
Prospective Fault current measured by instruments must be higher than
Ia of the protective device concerned
Practical example of verification of the protection in a TN system according to
the international Standard IEC 60364.
Fig.9
Rating
(A)
Disconnecting time 5s
Ia (A) Zs ( Ω ) Ia (A) Zs ( Ω )
Disconnecting time 0.4s
6
10
16
20
25
32
40
50
63
80
100
28
46
65
85
110
150
190
250
320
425
580
8.2
5
3.6
2.7
2.1
1.53
1.21
0.92
0.71
0.54
0.39
47
82
110
147
183
275
320
470
550
840
1020
4.9
2.8
2.1
1.56
1.25
0.83
0.72
0.49
0.42
0.27
0.22
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