What is breaking capacity in mcb?

Answer 1

I haven't heard of this in relation to a breaker. Breakers will have ratings for short circuit interrupting, max voltage, line charging, etc. A load break switch will have a "breaking capacity", meaning it can be opened as long as the load current is below the breaking rating.

Answer 2

Icu stands for Ultimate breaking capacity is a short circuit breaking capacity from the r.m.s prospective current that the circuit breaker is capable of breaking at a specified

voltage under defined test conditions, which include one break and one make/break operations. more information: http://www.voltimum.co.uk/files/gb/others/U/2006011968321430BEAMATechnicalBulletin.pdf

Answer 3

The interrupting rating of a breaker relates to the amount of current the breaker can interrupt. Think of current as a linebacker - The bigger he is, the harder it is to stop him dead in his tracks. That's what a circuit breaker does when it opens up large amounts of current. If the line backer is too big (more current than the breaker is rated for), he will just keep coming, and force the breaker back closed (in reality, parts of the breaker will probably melt, causing a plasma bridge between contacts, which will cause more heating until catastrophic failure occurs).

Answer 4

e must know load of perticular equipment. For Ex. Our load in MVA is 50 MVA Our system voltage(MCB,MCCB,ACB) is 440V. I(Bre)= 50/(1.73x0.440)=65.6 =Approx 65KA. Our load in MVA is 20 MVA Our system voltage(MCB,MCCB,ACB) is 440V. I(Bre)= 20/(1.73x0.440)=26.2 =Approx 25KA

Answer 5

A molded case circuit breaker is probably the most common in use for residential and low voltage applications in industrial settings. A MCCB is rated for max current and max interrupting capacity. I have seen 600 A MCCB in use. This is the "carry current" or heat rating. The current interrupting rating is different and depends on the c=breaker.

Answer 6

A circuit is a path that ends where it starts, like a race track. One lap is one trip around the circuit. Electricity only flows in circuits composed mainly of wires connecting power sources and loads. Turning off the electricity involves disconnecting a wire in the circuit, also called opening the circuit, or "breaking the circuit." Reconnecting or turning on the circuit is also called closing or "making" the circuit. Making and breaking are called switching.

Switchgear normally refers to an assembly of conductors and supporting structures designed to switch, i.e., Make and Break, connections, usually in high power circuits with capacity of hundreds to thousands of amps. This discussion applies equally to any circuit ampacity.

When a switch opens a circuit, an electrical arc forms between its contacts and, similar to arc welding, this arc readily melts metal, so its energy must be controlled to keep it from melting and destroying the switch. The part of the switch that quenches the arc is often called the "arc chute." Also, if the switched contacts do not have enough metallic mass, a high current can "spot weld" them together before the switch (e.g., circuit breaker) can be automatically opened.

The most current a switch can be expected to pass is called the "short circuit current" that occurs when the load that limits the circuit's current is bypassed with a "short" or inadvertent connection.

So the BREAKING CAPACITY of SWITCHGEAR is the most current a switch can pass without melting down, welding together or exploding, when opening a circuit under full load or short circuit conditions.

To select a proper size switch, the available fault (short circuit) current must be determined and it is limited by the ability of the power source to provide power and the resistance (more properly impedance) of all the components supplying the switch. This fault current determines how much energy would be available if an arc flash occurs, and also determines what level of PPE (Personal Protective Equipment) an electrician would be required to use if working on a "live" or "hot" or "energized" circuit, which is normally forbidden. PPE might include: insulating gloves, flame retardant clothing, insulated boots (no nails in the soles}, face shield, flame suit, Ultra-violet blocking face shield, and external breathing apparatus. Thus the importance of knowing the breaking capacity of switchgear.

Answer 7

There isn't a 'standard' breaking capacity for circuit breakers. It varies according to the load supplied by the circuit breaker and the calculated overcurrent for that load.

Answer 8

what is meaning breaking capacity breaker