12
IZM32 / IN32 low voltage air circuit breaker
MN013017EN May 2022 www.eaton.com
Section 2: Receiving, handling, and installation
2-10 Technical data
Ambient temperature
Derating coefficients are given in the table below when the circuit breaker is operating at different internal ambient
temperatures inside the panel. The ambient temperature inside the panel is determined with IEC8900, calculation methods
or equivalent methods.
Rated currents of the circuit breakers at different ambient temperature
Bus bar dimensions
The bus bar sizes are shown in the table below. This table uses data specified by IEC 60947-1 or obtained by Eaton in
their circuit breaker testing. They are 3-meter-long bus bars with the faces vertical and painted flat black. For other bus
bar configurations, larger bus bar sizes may be required or the breaker may have to be de-rated. Refer to the table (Rated
currents of the circuit breakers at different ambient temperature) presented in this section for de-rating information at higher
ambient temperature. Two example diagrams are recommended below.
Rated Current 800A
1000A
1250A
1600A
2000A
2500A
3200A
4000A
IZM32
40°C [A]
800
1000
1250
1600
2000
2500
3200
4000
50°C [A]
800
1000
1250
1600
2000
2500
3100
4000
60°C [A]
800
1000
1250
1600
2000
2500
2800
3650
70°C [A]
800
1000
1250
1600
2000
2500
2550
3500
(T)
(5mm)
(60mm)
(W)
T = Thickness of bus bar
w = Width of bus bar
2 stacked 5mm × 60 mm bus bars to carry 800A
Example 1
Example 2
Max. operating current A
(ambient temperature 40°C)
Circuit breaker frame size
(
IZM32
)
Recommended bus bar quantities and sizes
(mm)
(I
n
)
800
08
(2) 5 x 50
(1) .25 x 3.0
1000
10
(2) 5 x 60
(2) .25 x 2.0
1250
12
(2) 5 x 80
(2) .25 x 3.0
1600
16
(2) 5 x 100
(2) .25 x 3.0
2000
20
(3) 5 x 100
(3) .25 x 3.0
2500
25
(4) 5 x 100
(4) .25 x 3.0
3200
32
3) 10 x 100
(3) .25 x 6
4000
40
4) 10 x 100
(4) .25 x 6
