Bay Power Location in Roseville, CAAre you researching circuit breakers for your next project or trying to replace an old, worn-out breaker? To choose the right one, you’ll need to know the requirements of your application and the specifics of the breaker itself (such as trip mechanisms, mounting hardware, voltage, and amperage). In this post, we’ll give you a helicopter view of four different types of circuit breakers and their applications.  


Molded case circuit breakers (MCCB) contain all components within an insulated molded case. They can be used in almost any environment, from residential applications to industrial or commercial systems. MCCBs protect against short circuits, ground faults, and thermal overloads using thermomagnetic and electromagnetic mechanisms to trip the breaker and interrupt the flow.

MCCB Applications

MCCB frame sizes range from 250 to 2000 amps. They can be rated as low as 75A, making them ideal for low voltage environments. They can also be used in medium voltage applications such as industrial or commercial control panels and switchboards.


Insulated case circuit breakers (ICCB) also enclose all components within an insulated case. The difference is that they include a 2-step stored energy mechanism and they are available in larger frame sizes and higher amp ratings than MCCBs. Constructed with both fixed-mount or draw-out enclosures, they are made entirely of plastic, with no metal components on the frame.

ICCB Applications

Higher ratings and larger frame sizes ranging from 800 to 5000 amps give ICCBs more versatility than some other breakers. They are commonly used for low voltage industrial applications and can replace old air circuit breakers in some circumstances.


Vacuum circuit breakers are so named because the electrical arc interruption takes place in a vacuum. Usually housed in glass or ceramic, they are compact and low maintenance with less fire hazard potential than other kinds of breakers.

Vacuum Circuit Breaker Applications

Vacuum circuit breakers are most commonly used in medium voltage industrial and commercial applications such as hotels, water treatment plants, healthcare facilities, and power plants. Common models include 6.6 kV, 11 kV, and 33 kV.


Unlike MCCBs and ICCBs, air circuit breakers operate in the open, without an enclosed case. This makes them easy to modify or recondition as needed. They aren’t as commonly used as other types of circuit breakers, but they can operate on both AC and DC circuits with either fixed or draw-out enclosures.

Air Circuit Breaker Applications

Most air circuit breakers are used for indoor, low voltage applications, although they sometimes offer a good solution for medium voltage environments as well.


These are just a few of the types of circuit breakers and applications on the market. Choosing the right one takes careful consideration of the breaker’s design and amp load, as well as its intended use.

If you need help finding the right breaker or replacing an old breaker, call Bay Power at 866-543-1231. We’re always ready to answer your questions or provide a quote!

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