Siemens 3 Pole 70 kA VL 250 MCCB Microprocessor Based Trip Unit 3VL Series (ETU10)

Siemens MCCB is a type of circuit breaker which is used when load current exceeds the limit of a miniature circuit breaker. The MCCB provides protection against overload, short circuit faults and is also used for switching the circuits. It can be used for higher current rating and fault level even in domestic applications. The wide current ratings and high breaking capacity in MCCB find their use in industrial applications. MCCB can be used for protection of capacitor bank, generator protection and main electric feeder distribution. It offers adequate protection whenever an application requires discrimination, adjustable overload setting or earth fault protection.

The MCCB is made up of two parts namely:

1) A molded case which encloses all other components

2) An operating mechanism which consists of a trip mechanism, an operating handle, an operating mechanism housing, a magnetic trip unit and so on

The molded case has two separate chambers i.e., the upper chamber contains all internal connections while lower chamber has connection points which are accessible from outside through plug-in connectors. The upper chamber contains thermal-magnetic trip unit along with contactors whereas lower chamber contains fuses and auxiliary contacts as well as other components like push buttons etc.

MCCB are available in different shapes like DIN Rail mounting type, Screw mounting type, Surface mounting type etc., according to application requirements.