Mould Case Circuit Breaker (MCCB) is a mechanical device, capable of making, carrying

and breaking currents under normal circuit conditions and also making, carrying for a

specified time and breaking currents under specified abnomal circuit conditions such as

short-circuit and over-current.

Operating Principle of Mould Case Circuit Breaker (MCCB):

Most important function of the circuit breaker is the protection of the circuit at the abnormal

operating conditions besides making, carrying and breaking the currents. MCCBs are

equipped with some units to carry out protection function. Opening units of low voltage

circuit breakers are defined as a release according to EN/IEC60947-2 standards and CE

certificate.

Releases:

A release which permits a MCCB to open, without any intentional time delay.

• Overcurrent releases
• 
  Undervoltage releases
• 
  Shunt releases

All of the breakers are equipped with over current releases. Undervoltage and shunt

releases are not standard accessories, but they can be fixed on the MCCB by the request

of customer.

Overcurrent Releases:

General:

A release which causes a mechanical switching device to open with or without time-delay

when the current in the release exceeds a predetermined value.

How overcurrent occurs...?

Values of all currents which exceeds to the rated currents are defined as overcurrent.

Overcurrent occurs when there is an increase in the power, which is being absorbed from

the circuit or when a short circuit occurs. Both of the overcurrents are dangerous for

electrical circuits. Overcurrents cause thermal and dynamic forces in electrical circuits.

Overcurrents which occur with increasing the power can be 2 or 3 fold from rated current.

Due to short-circuit current, abnormally high current occurs according to feature of electrical

circuit. For example this can be 3.2kA at 100kVA transformer and 60kA at the 2500kVA

transformer.

Electrical devices such as transformers, generators, motors, capacitors, cables...etc. Have

a value of withstand against the thermal and dynamic forces due to when a short-circuit

occurs, the overcurrent passing through the circuit causes a temperature rise. The value of

current is so important as well as the period of time of current. When current builds up, it is

necessary to decrease the time of flow current in order to hold the I2t value less than

determineted value. Low voltage circuit breakers provide confident protection by opening

the circuit under the I2t value for device.

• Rated Current.............................................................40A
• Frame Current.............................................................50A
• No. of Pole...................................................................3-POLE
• Rated Insulated Voltage.............................................690VAC
• Frequency....................................................................50/60Hz
• Standards................................................................EN/IEC60947,EN/IEC60898-1
• IP/NEMA Rating.........................................................IP20
• Connection..................................................................Screw+Cable Lug
• Working Temperature................................................-5℃~+50℃
• Mechanical Life.......................................................... 20,000 times
• Sample Service...........................................................Pay to Provide
• Quality Assurance......................................................24 months
• Item Condition.............................................................Brand-New