Scope of application
The CFM5 series of molded case circuit breakers, with a rated insulation voltage of 1000V, are suitable for power distribution networks with an alternating current frequency of 50Hz, a rated operating voltage of 690V and below, and a rated operating current of up to 630A. They are used to distribute electrical energy and protect lines and power supply equipment from damage caused by faults such as overload, short - circuit, and undervoltage. Under normal conditions, they can be used for infrequent switching of lines and infrequent starting of motors, and can also provide overload, short - circuit, and undervoltage protection for motors.

Structural features
The circuit breaker adopts a double - break structure, featuring small size, high breaking capacity, short arcing distance, and vibration resistance.
The circuit breaker has a thermo - magnetic adjustable function, and accessories such as shunt trip units, undervoltage trip units, auxiliary contacts, and alarm contacts can be added.

Operating conditions
· Ambient air temperature: - 40°C to + 70°C, with a 24 - hour average not exceeding + 35°C. The normal operating ambient temperature range is - 5°C to + 40°C. For operating conditions in an ambient temperature range of - 40°C to - 5°C, it is necessary to inform the factory when placing an order. When the ambient temperature is higher than + 40°C, derating is required. The derating factor is shown in Table 4.
· Altitude: The altitude of the installation location is ≤ 2000m. Special customization is available for installations at altitudes from 2000m to 5000m, and derating is required. The operating performance should be corrected according to the correction values in Table 3.
· Atmospheric conditions: When the maximum temperature is + 40°C, the relative air humidity does not exceed 50%. At lower temperatures, a higher relative humidity is possible; for example, it can be 90% at 20°C. Special measures should be taken for occasional condensation caused by temperature changes.
· Pollution degree: Class 3;
· Installation category: Category III;
· Installation conditions: The circuit breaker can be installed vertically or horizontally.