Temperature
The following temperatures are relevant for circuit breakers:
-
Ambient temperature: the temperature of the air immediately surrounding the circuit breaker. If the temperature inside the enclosure is above 40 °C (104 °F), devices must be derated.
-
Operating temperature range: -25 °C to +70 °C (-13 °F to +158 °F).
NOTE: Commissioning is possible down to -35 °C (-31 °F). -
Storage temperature range: -50 °C to +85 °C (-58 °F to +185 °F).
The following table gives the standard circuit breaker ampere ratings depending on the frame rating and the operating temperature in the enclosure.
|
Temperature |
Frame Rating In (A) |
||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
°C |
°F |
15 to 125 |
|||||||||||||||
|
40 |
104 |
15 |
20 |
25 |
30 |
35 |
40 |
45 |
50 |
60 |
70 |
80 |
90 |
100 |
110 |
125 |
|
|
45 |
113 |
14 |
19 |
24 |
29 |
34 |
39 |
44 |
49 |
58 |
67 |
77 |
87 |
99 |
107 |
121 |
|
|
50 |
122 |
14 |
19 |
24 |
28 |
33 |
38 |
42 |
47 |
56 |
64 |
73 |
83 |
96 |
103 |
117 |
|
|
55 |
131 |
13 |
18 |
23 |
27 |
32 |
37 |
41 |
45 |
55 |
61 |
70 |
80 |
92 |
99 |
112 |
|
|
60 |
140 |
12 |
18 |
22 |
26 |
31 |
36 |
39 |
44 |
53 |
59 |
67 |
76 |
85 |
94 |
109 |
|
|
65 |
149 |
12 |
17 |
21 |
25 |
31 |
35 |
37 |
42 |
51 |
55 |
63 |
72 |
80 |
89 |
104 |
|
|
70 |
158 |
11 |
16 |
20 |
24 |
30 |
33 |
36 |
40 |
48 |
53 |
59 |
68 |
69 |
76 |
100 |
|
The following table gives the correction factor that applies to tripping time depending on ambient temperature:
|
Temperature |
Frame Rating In (A) |
||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
°C |
°F |
15 |
20 |
25 |
30 |
35 |
40 |
45 |
50 |
60 |
70 |
80 |
90 |
100 |
110 |
125 |
|
|
10 |
50 |
1.21 |
1.16 |
1.15 |
1.16 |
1.13 |
1.14 |
1.17 |
1.16 |
1.16 |
1.18 |
1.19 |
1.19 |
1.21 |
1.19 |
1.17 |
|
|
15 |
59 |
1.18 |
1.13 |
1.13 |
1.14 |
1.14 |
1.14 |
1.14 |
1.14 |
1.14 |
1.14 |
1.14 |
1.14 |
1.14 |
1.14 |
1.14 |
|
|
20 |
68 |
1.15 |
1.11 |
1.11 |
1.11 |
1.09 |
1.10 |
1.12 |
1.11 |
1.11 |
1.13 |
1.12 |
1.12 |
1.15 |
1.13 |
1.12 |
|
|
25 |
77 |
1.11 |
1.08 |
1.08 |
1.08 |
1.07 |
1.07 |
1.09 |
1.08 |
1.08 |
1.10 |
1.0 |
1.10 |
1.12 |
1.10 |
1.09 |
|
|
30 |
86 |
1.08 |
1.06 |
1.05 |
1.06 |
1.05 |
1.05 |
1.06 |
1.06 |
1.06 |
1.06 |
1.06 |
1.06 |
1.09 |
1.07 |
1.06 |
|
|
35 |
95 |
1.04 |
1.03 |
1.03 |
1.03 |
1.02 |
1.03 |
1.03 |
1.03 |
1.03 |
1.03 |
1.03 |
1.04 |
1.05 |
1.04 |
1.03 |
|
|
40 |
104 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
|
|
45 |
113 |
0.96 |
0.97 |
0.97 |
0.97 |
0.98 |
0.97 |
0.97 |
0.97 |
0.97 |
0.96 |
0.96 |
0.99 |
0.99 |
0.98 |
0.96 |
|
|
50 |
122 |
0.92 |
0.94 |
0.94 |
0.94 |
0.95 |
0.95 |
0.94 |
0.94 |
0.94 |
0.92 |
0.92 |
0.96 |
0.94 |
0.94 |
||
|
55 |
131 |
0.87 |
0.91 |
0.91 |
0.91 |
0.93 |
0.92 |
0.90 |
0.91 |
0.91 |
0.88 |
0.88 |
0.89 |
0.92 |
0.90 |
0.90 |
|
|
60 |
140 |
0.83 |
0.88 |
0.88 |
0.87 |
0.90 |
0.89 |
0.87 |
0.87 |
0.88 |
0.84 |
0.83 |
0.84 |
0.85 |
0.85 |
0.87 |
|
|
65 |
149 |
0.78 |
0.85 |
0.85 |
0.84 |
0.87 |
0.86 |
0.83 |
0.84 |
0.84 |
0.79 |
0.79 |
0.80 |
0.80 |
0.80 |
0.83 |
|
|
70 |
158 |
0.72 |
0.81 |
0.82 |
0.80 |
0.85 |
0.83 |
0.79 |
0.80 |
0.81 |
0.75 |
0.74 |
0.75 |
0.69 |
0.70 |
0.80 |
|