pplicable Standards
● GB/T 14048.1 General Rules
● GB/T 14048.2 Circuit-breakers
● IEC 60947-1 General Rules
● IEC 60947-2 Circuit-breakers
Pollution Degree
● CDMU series products operate in Pollution Degree 3.
● As defined by standards IEC 60947-1 and IEC 60664-1 for environments (industrial environments).
Resistance to Damp Heat
● Dry cold, dry heat, damp heat.
Ambient Temperature
● The CDMU series can operate continuously under normal environmental and operating temperature conditions from -5°C to 40°C.
● If the operating ambient temperature exceeds 40°C (or 60°C for motor protection), refer to the temperature derating factor tables for use.
● Storage temperature range is
-20°C to 70°C.
Altitude
● Normal operating installation altitude does not exceed 2000m.
● For installations at altitudes exceeding
2000m, changes in dielectric strength and air cooling effects must be considered; refer to the altitude derating factor tables for use.
Humidity
● Normal operation requires:
- Relative humidity not exceeding 50% at an ambient air temperature of +40°C.
- At lower temperatures, higher relative humidity is permissible.
- The monthly average relative humidity of the wettest month is 90%.
● Consider the impact of condensation on the product surface on product performance.
Reliable Contact Position Indication with Isolation Function
● All CDMU series Molded Case Circuit Breakers (MCCBs) comply with the isolation requirements defined in IEC standard 60947-2.
- The isolation position corresponds to the "0" (OFF) position.
- The operating handle can only indicate the "OFF" position when the contacts are physically open.
- The reliability of the contact position indication system is
not affected by the use of a rotary handle or an electrical operating mechanism.
The isolation function, as tested, must ensure:
● Mechanical reliability of the contact position indication system.
● No leakage current.
● Adequate overvoltage withstand capability between the line and load terminals.
Protection Class (IP Rating)
● Breaker body: IP20.
● Breaker installed in a switchgear panel:
- Breaker with toggle handle: IP40.
- Breaker with electrical operating mechanism: IP40.