General Catalogue 2007 - Ibemo Kazakhstan Ltd

Earth loop impedance (Z s ) values for MCBs & MCCBs
Below are the maximum permissible values of Z s to obtain
disconnection in 0.4 & 5 seconds
Rated Max let-through Max Zs (ohms)
trip energy (kA2s) at PSCC 0.4 5
Type In 3kA 6kA 10kA Secs Secs
MTN/ 6 5.9 10.5 15 8 8.8
NBN 10 6.5 12.2 21.5 4.8 5.33
B curve 16 8.0 17.5 30 3 3.33
20 8.8 19.5 34 2.4 2.66
25 10 21 38 1.92 2.14
32 11 24 42 1.5 1.66
40 12.5 29 50 1.2 1.33
50 15 34 61 0.96 1.06
63 16 38 72 0.76 0.84
NCN/HM 0.5 0.01 0.01 0.01 48 120
C curve 1 4.0 7.0 10 24 53
2 4.0 7.0 10 12 26
3 5.0 10.0 15 8 18.78
4 5.9 10.5 15 6 13.56
6 5.9 10.5 15 4 8.8
10 6.5 12.2 21.5 2.4 5.33
16 8.0 17.5 30 1.5 3.33
20 8.8 19.5 34 1.2 2.66
25 10 21 38 0.96 2.14
32 11 24 42 0.75 1.66
40 12.5 29 50 0.6 1.33
50 15 34 61 0.48 1.06
63 16 38 72 0.38 0.84
80 0.30 0.66
100 0.24 0.53
NDN 6 5.9 10.5 15 2 8.8
D curve 10 6.5 12.2 21.5 1.2 5.33
16 8.0 17.5 30 0.75 3.33
20 8.8 19.5 34 0.6 2.66
25 10 21 38 0.48 2.14
32 11 24 42 0.37 1.66
40 12.5 29 50 0.3 1.33
Table 40
50 15 34 61 0.24 1.06
63 16 38 72 0.19 0.84
Hager Catalogue 2007 • Technical
Circuit Breaker Z s Values &
Energy Let Through
Rated
trip
Max Z (ohms)
s
0.4 5
Type
H125 fixed mag.
In secs secs
trip 16 0.2 1.9
20 0.2 1.5
25 0.2 1.2
32 0.2 0.94
40 0.2 0.75
50 0.2 0.6
63 0.2 0.48
80 0.2 0.38
100 0.2 0.3
H 250 mag. trip
125 0.2 0.24
set to max 160 0.125 0.125
200 0.10 0.10
250 0.08 0.08
H 250 mag. trip
set to min 160 0.25 0.25
200 0.20 0.20
H 400 mag. trip
250 0.16 0.16
set to max 320 0.06 0.06
H 400 mag. trip
400 0.05 0.05
set to min 320 0.13 0.13
H 800 mag.
400 0.10 0.10
set to max 500 0.05 0.05
630 0.03 0.03
H 800 mag. trip
800 0.03 0.03
set to min 500 0.10 0.10
630 0.06 0.06
Table 41
800 0.05 0.05
These values have been calculated using the formula
Z s = Uoc/la taken from appendix 3 of BS EN7671: 1992, taking into
account the 20% tolerance stated in section 8.3.3.1.2 of BS EN
60947-2. Uoc is the open circuit voltage of the REC transformer
taken at 240V. Ia is the current causing operation of the protective
device within the specified time. Calculate from Im x 1.2.
Full table as Apps guide (Table 27)
ibemo Kazakhstan - 090301 Republic of Kazakhstan, West Kazakhstan Oblast, Aksai, Pramzone, BKKS office complex
Phone: +7 71133 93077 ; Fax: +7 71133 93074 ; E-Mail: info@ibemo-kz.com
3.55
Protection
Devices