An MCCB or a molded case circuit breaker is a kind of electrical protection device that plays a crucial role in guarding the electrical circuit again high current, which can lead to a short circuit or an overload. With maximum current ratings of 2500A, MCCBs can be utilized for a wide range of frequencies and voltages with adjustable trip settings.
Since MCCBs are used in large-scale PV systems, they are ideal for the purpose of system isolation and protection in the workspace. So, if you are planning to purchase these products for your commercial building but aren’t sure which type to look for, don’t worry. We have got you covered. In this blog, we will explain the different kinds of MCCBs available in India.
Sizing of MCCBs
Before we explore the different kinds of MCCBs, let us understand the sizing of an MCCB. Ideally, MCCBs must be sized based on the electrical circuit’s anticipated operating current and potential fault currents. The three key criteria for sizing the MCCBs are given below.
Breaking Capacity
The breaking capacity of an MCCB should be more than the theoretical possible fault currents so that it trips in case of a fault.
Trip Value
An MCCB’s trip value must be adjusted in accordance with the current drawn by the load.
Rated Working Voltage
An MCCB’s rated working voltage (Ue) must be equal to the voltage of the system.
Types of MCCBs Available
Now that you are aware of how an MCCB is sized, let us understand the various types of MCCBs available in India.
Type B
The range of operating current in Type B MCCBs trips between 3 and 5 times in the entire rated current. The operating time varies from 0.04 to 13 seconds. This makes it ideal for domestic applications, especially due to the fact that these have resistive load applications and low surge currents.
Type C
This type of MCCB trips between five and 10 times the rated current input and has a response time between 0.04 and 5 seconds. Moreover, the surge current is moderate. This makes it highly useful in commercial and industrial areas.
Type D
Type D MCCBs have inductive-capacitive load applications, such as large winding motors, motors, and pumps, due to the high surge current. These products trip between 10 and 20 times rated current and have an operating response time between 0.04 and 3 seconds.
Type K
Type K MCCBs trip between eight and 12 times rated current and have a minimum response time of 0.04 seconds and a maximum response time of 5 seconds. Its industrial applications involve inductive and motor loads with high inrush currents.
Type Z
MCCBs that belong to this category trip between 2 and 3 times rated current and have a response time between 0.04 seconds. Their surge current is very low. In fact, they are highly sensitive to short circuits and are utilized for the protection of highly sensitive devices like semiconductors.
Kinds of MCCBs by Application
While we have mentioned above the various kinds of MCCBs, it is better to know their types based on application. This will help you understand better.
Low Current Applications
MCCBs are not just for high current environments. There are MCCB products that are rated less than 100A for times when low current equipment needs adjustable trip settings that MCCBs offer.
Application in Welding
Some welding machines tend to draw high currents, which are beyond the capabilities of MCBs. this implies the need for an MCCB.
Protection of Generators
Large electrical generators provide an output of hundreds of amperes. The high current ratings of MCCBs enable them to offer reliable protection in the case of these generators.
Protection of Capacitor Bank
Capacitor banks are highly crucial in industrial as well as commercial electrical systems. This is because they enable power factor correction, decreasing line currents and preventing charges from electrical utility companies. Since large capacitor banks draw high currents, they require MCCBs for their protection.
Final Word
There are five different kinds of MCCBs available in India, namely Type B, Type C, Type D, Type K, and Type Z. Of these, Type C, D, and K have industrial and commercial applications. So, if you are looking to purchase MCCBs for your commercial space, you should consider these types of MCCBs, based on your requirements. You can explore a wide variety of MCCBs online on L&T-SuFin and then make the purchasing decision according to your needs.