Low Voltage Mini Micro Miniature Circuit Breaker 

Special tips:

MCB is for non-professional operation by those untrained, and no maintenance is required.

Satisfying conditions and applications as mentioned above, MCB with "ON-OFF"

indicating devide is considered suitable for isolation function.

Particular devices such as surge protective devices, surge arrester etc are recommended

to install at upstream line to MCB as precaution against potential surge voltage and current

occurring at its power input side.

Appropriate tripping curve being chosen and properly installed, MCB trips and switches off

its protected circuit in case of fault, and thus provides protection against electric shock.

Inside of a MCB

Tripping curve:

B curve:

Recommended for household lighting and control circuits, etc.

Instantaneous tripping current: 5In.

Instantaneous non-tripping current: 3In.

Application: provides protection to circuits with low inductive load.

C curve:

Recommended for transformers, inductive loads like florescent lamps.

Instantaneous tripping current: 10In.

Instantaneous non-tripping current: 5In.

Application: provides protection to circuits with inductive load or to highly inductive

illumination system.

D curve:

Instantaneous tripping current: 20In.

Instantaneous non-tripping current: 10In.

Application: provides protection to circuits with high inductive load or electric distribution

system with high surge current. 

Low-voltage circuit breakers

Low-voltage (less than 1,000 VAC) types are common in domestic, commercial and

industrial application, and include:

•  MCB (Miniature Circuit Breaker)—rated current not more than 100 A. Trip characteristics normally not adjustable. Thermal or thermal-magnetic operation. Breakers illustrated above are in this category.

There are three main types of MCBs: 1. Type B - trips between 3 and 5 times full load

current; 2. Type C - trips between 5 and 10 times full load current; 3. Type D - trips

between 10 and 20 times full load current. In the UK all MCBs must be selected in

accordance with BS 7671.

•   MCCB (Molded Case Circuit Breaker)—rated current up to 2,500 A. Thermal or thermal-magnetic operation. Trip current may be adjustable in larger ratings.
• Low-voltage power circuit breakers can be mounted in multi-tiers in low-voltage switchboards or switchgearcabinets.

The characteristics of low-voltage circuit breakers are given by international standards

such as IEC 947. These circuit breakers are often installed in draw-out enclosures

that allow removal and interchange without dismantling the switchgear.

Large low-voltage molded case and power circuit breakers may have electric motor

operators so they can open and close under remote control. These may form part of

an automatic transfer switch system for standby power.

Low-voltage circuit breakers are also made for direct-current (DC) applications, such

as DC for subway lines. Direct current requires special breakers because the arc is

continuous—unlike an AC arc, which tends to go out on each half cycle. A direct

current circuit breaker has blow-out coils that generate a magnetic field that rapidly

stretches the arc. Small circuit breakers are either installed directly in equipment, or

are arranged in a breaker panel.

The DIN rail-mounted thermal-magnetic miniature circuit breaker is the most common

style in modern domestic consumer unitsand commercial electrical distribution

boardsthroughout Europe. The design includes the following components:

1.Actuator lever - used to manually trip and reset the circuit breaker. Also indicates

the status of the circuit breaker (On or Off/tripped). Most breakers are designed so

they can still trip even if the lever is held or locked in the "on" position. This is

sometimes referred to as "free trip" or "positive trip" operation.

2.Actuator mechanism - forces the contacts together or apart.

3.Contacts - Allow current when touching and break the current when moved apart.

4.Terminals

5.Bimetallic strip - separates contacts in response to smaller, longer-term overcurrents

6.Calibration screw - allows the manufacturer to precisely adjust the trip current of the

device after assembly.

7.Solenoid - separates contacts rapidly in response to high overcurrents

Arc divider/extinguisher

• Rated Current...................................................25A
• No. of Pole........................................................1-Pole
• Function.....................................Protection from Short-circuit and Overloads.
• Rated Insulated Voltage.................................690VAC
• Rated Voltage............................................1-Pole 230V AC;2,3,4-Pole 400V AC
• Frequency........................................................50/60Hz
• Operation Series.............................................Bimetal 
• IP / NEMA Rating.............................................IP20
• Working Temperature....................................-5°C~+50°C
• Altitude............................................................≤2,000m

• Relative Humidity..........................≤50%@Max.+40°C, (NOTE: allow higher humidity with low temperature less than 40°C  eg.:humidity 90%@20°C)

• Standards........................................................IEC60898-1,EN60898-1
• Mechanical Life...............................................20,000times
• Pollution Rating..............................................Class III
• Installation........................Flush type (vertically mounted in distribution box)
• Sample Service...............................................Pay to provide
• Quality Assurance..........................................12 months
• Item Condition................................................Brand-New