0611CT1603

Temperature Considerations

Correction Factor

The overload protection is calibrated at 40°C. This means that when the ambient temperature is less than or greater than 40°C, the In protection pick-up is slightly modified.

Derating Depending on the Temperature

Over the reference temperature of 40°C (104°F), the circuit breaker has to be derated following the table below:

Correction Factor Table for PowerPact B-frame Circuit Breakers

Rating (In)

(A)

Temperature (°C / °F )

40 / 104

45 / 113

50 / 122

55 / 131

60 / 140

65 / 149

70 / 158

15

15

14

14

13

12

12

11

20

20

19

19

18

18

17

16

25

25

24

24

23

22

21

20

30

30

29

28

27

26

25

24

35

35

34

33

32

31

31

30

40

40

39

38

37

36

35

33

45

45

44

42

41

39

37

36

50

50

49

47

45

44

42

40

60

60

58

56

55

53

51

48

70

70

67

64

61

59

55

53

80

80

77

73

70

67

63

59

90

90

87

83

80

76

72

68

100

100

99

96

92

85

80

69

110

110

107

103

99

94

89

76

125

125

121

117

112

109

104

100

Calculating Tripping Time

Calculating the Tripping Time for a Given Temperature:

After having determine the corrected ratio I/In, the tripping time at 40°C (104°F) is defined with the tripping curves (Trip Curves). Then to obtain the tripping time at a different temperature, the ratio I/In has to be corrected with the correction factor below:

Correction Factor Table for PowerPact B–Frame Circuit Breakers

Rating (In)

(A)

Temperature °C (°F )

10
(50)

15
(59)

20
(68)

25
(77)

30
(86)

35
(95)

40 (104)

45 (113)

50 (122)

55 (131)

60 (140)

65 (149)

70 (158)

15

1.21

1.18

1.15

1.11

1.05

1.04

1

0.96

0.92

0.87

0.83

0.78

0.72

20

1.16

1.13

1.11

1.08

1.06

1.03

1

0.97

0.94

0.91

0.88

0.85

0.81

25

1.15

1.13

1.11

1.08

1.05

1.03

1

0.97

0.94

0.91

0.88

0.85

0.82

30

1.16

1.14

1.11

1.08

1.06

1.03

1

0.97

0.94

0.91

0.87

0.84

0.80

35

1.13

1.11

1.09

1.07

1.05

1.02

1

0.98

0.95

0.93

0.90

0.87

0.85

40

1.14

1.12

1.10

1.07

1.05

1.03

1

0.97

0.95

0.92

0.89

0.86

0.83

45

1.17

1.15

1.12

1.09

1.06

1.03

1

0.97

0.94

0.90

0.87

0.83

0.79

50

1.16

1.14

1.11

1.08

1.06

1.03

1

0.97

0.94

0.91

0.87

0.84

0.80

60

1.16

1.14

1.11

1.08

1.06

1.03

1

0.97

0.94

0.91

0.88

0.84

0.81

70

1.18

1.15

1.13

1.10

1.06

1.03

1

0.96

0.91

0.88

0.84

0.79

0.75

80

1.19

1.15

1.12

1.09

1.06

1.03

1

0.96

0.92

0.88

0.83

0.79

0.74

90

1.19

1.15

1.12

1.10

1.06

1.04

1

0.96

0.92

0.89

0.84

0.80

0.75

100

1.21

1.18

1.15

1.12

1.09

1.05

1

0.99

0.96

0.92

0.85

0.80

0.69

110

1.19

1.16

1.13

1.10

1.07

1.04

1

0.98

0.94

0.90

0.85

0.80

0.70

125

1.17

1.14

1.12

1.09

1.06

1.03

1

0.96

0.94

0.90

0.87

0.83

0.80

QR code for this page

Was this helpful?