Scope of Application
● The KFM3X series Molded Case Circuit Breakers (hereinafter referred to as circuit breakers) are suitable for circuits with AC 50/60Hz, rated voltage up to 690V, and rated current up to 800A. They are generally used for distribution purposes. Circuit breakers with rated currents up to 630A can also be used for motor protection.
● Distribution circuit breakers are used in distribution networks to distribute electrical energy and provide overload, short-circuit, and undervoltage protection for lines and power supply equipment, meeting the requirements for "Selection of Electrical Apparatus" in GB50054.
● Motor protection circuit breakers can be used in distribution networks for starting and breaking squirrel-cage motors during operation, as well as providing overload and short-circuit protection. Their protection characteristics meet GB/T14048.4, and their application meets GB50055.
● The entire series features reliable contact indication and isolation functions, meeting the requirements for isolation devices in GB50054.
● Based on their rated ultimate short-circuit breaking capacity (Icu), the circuit breakers are classified into four types: C Type (Economical), S Type (Standard), M Type (Higher Breaking Capacity), and H Type (High Breaking Capacity).
●
KFM3X series circuit breakers of breaking capacity classes C, S, and M have reverse connection capability when used in AC 400V distribution systems.
Operating Environment and Installation Conditions
Ambient Operating Temperature
● Ambient air temperature: -40°C to +70°C. If the ambient temperature exceeds +40°C, derating by the customer is required. Refer to the "Derating Coefficient Table for Ambient Temperature Changes".
Storage Conditions
● Ambient air temperature: -40°C to +70°C.
Altitude
● Installation site altitude not exceeding 2000m. Derating coefficients for high altitudes are provided in the "High Altitude Derating Coefficient Table".
Operating/Storage Relative Humidity
● The relative humidity of the air at the installation site should not exceed 50% at the maximum temperature of +40°C. Higher relative humidity is permissible at lower temperatures, e.g., up to 90% at 20°C.
● Special measures should be taken against occasional condensation due to temperature changes.
Pollution Degree
● Degree 3.
Installation Category
● The installation category for the main circuit of the circuit breaker is Category III (Distribution and Control Level). The installation category for auxiliary and control circuits not connected to the main circuit is Category II (Load Level).
Installation Environment
● The circuit breaker should be installed in an atmosphere without explosive hazards and free from substances that corrode metal or degrade insulation.
● The circuit breaker should be installed in a location free from rain and snow intrusion.
● Tropical humid type (TH type) circuit breakers meet the test requirements of GB/T2423.4 and GB/T2423.18, capable of withstanding the effects of humid air, salt mist, oil mist, and mold.
Mounting Orientation
● The product must be mounted vertically. The inclination of the mounting surface relative to the vertical plane should be ≤ ±22.5°.
Compliance Standards
● IEC 60947-1 & GB/T 14048.1 Low-voltage switchgear and controlgear - General rules.
● IEC 60947-2 & GB/T 14048.2 Low-voltage switchgear and controlgear - Circuit-breakers.
● IEC 60947-4-1 & GB/T 14048.4 Low-voltage switchgear and controlgear - Contactors and motor-starters - Electromechanical contactors and motor-starters (including motor protection devices).