Search

Search

Derating of 3VA1 molded case circuit breakers

The temperature inside the molded case circuit breaker is influenced by the ambient temperature and the current-dependent power loss generated inside the unit. To prevent overloading of 3VA1 molded case circuit breakers under difficult thermal conditions, the maximum rated continuous operational current must be limited as a function of the ambient temperature.

NOTE

These values do not apply to all mounting conditions for molded case circuit breakers and may deviate depending upon factors such as cables and busbars, packing density, ventilation, etc.

Please observe the applicable overriding guidelines (e.g. IEC 61439).

Derating in combination with accessories

None of the accessories from the extensive range available for 3VA1 molded case circuit breakers has an influence on the thermal response thresholds of the switching devices except for two accessories that require additional correction factors. These are:

71674246923.png

No derating up to the rated operational current In of the molded case circuit breaker

71388126091_Table-1.png
71388126091_Table-2.png
71674246923.png

No derating up to the rated operational current In of the molded case circuit breaker

74208400395_Table-1.png
74208400395_Table-2.png
71674246923.png

No derating up to the rated operational current In of the molded case circuit breaker

74208515851_Table-1.png
74208515851_Table-2.png
71674246923.png

No derating up to the rated operational current In of the molded case circuit breaker

75838421259_Table-1.png
75838421259_Table-2.png