What is the Function of a Circuit Breaker?

Harnessing electricity for our own use has radically changed society over the past couple centuries, allowing us to achieve lighting during low-visibility conditions, create powerful electrical systems that make our daily operations easier, and so much more. While we have harnessed electricity and provided it to much of the world’s population, electricity still remains volatile and quite dangerous if not managed properly. Within a home, conditions such as electrical faults and surges can lead to various issues, potentially destroying electrical devices, harming individuals, and causing fires. As such, we have developed various ways to better protect ourselves and our surroundings from the hazards of electrical faults. One of the main ways in which we protect ourselves and our equipment is through the use of equipment known as circuit breakers, those of which we will discuss in detail in this blog.

In their most basic form, circuit breakers are a type of electrical switch that is capable of protecting a circuit by disconnecting power when current levels surpass safe levels. This generally occurs when a short circuit or other electrical fault occurs, often being sourced from an overabundance of appliances and devices being connected to the same circuit. This is because more power is needed than the circuit can handle, leading to issues. For short circuits, such conditions happen when electrical current flows into the wrong path. As circuit overloads can lead to various undesirable or unsafe conditions, it is very important to have a breaker in place.

While circuit breakers function to break a circuit during overload conditions, different types may utilize varying methods to carry this out. Nevertheless, most follow a somewhat similar process that describes their general functionality. However, before we discuss this, it is first useful to understand the common components of such devices.

The outermost shell of the circuit breaker is known as the frame, and this assembly is produced with the use of molded insulating materials. The frame is designed to protect all internal components in the instance of a hazard or fault. Within the frame, one can find the terminal, that of which is a metallic block where current-carrying wires are connected so that electricity can flow through the breaker during standard operations. In order for the circuit to be broken, two pieces of metal known as contacts open and close to manage the circuit. While one contact is situated on the main breaker panel, the other is placed on the actuator mechanism. The actuator mechanism itself is just a metal arm that is attached to the lever and contact. To flip the circuit breaker on and off, one can adjust the lever. The final major component is the trip unit, and this is the element that ensures the breaker automatically trips when an overload, short circuit, or fault ensues.

With this basic understanding of their makeup, it can be much easier to describe the actual operations of the circuit breaker. During normal conditions, the lever will be in the “on” position with contacts connected, allowing electricity to freely flow from the power supply, through the breaker, and to the rest of the circuit. When current exceeds safe conditions, a bi-metallic strip in the thermal magnetic trip unit will heat up until it bends, causing the contacts to separate so that power is shut off. This will also cause the lever to flip, and power will not resume until the issue subsides and the lever is either manually or automatically flipped back.

While circuit breakers are designed to be used many times, they will eventually break down and require part replacement or repair. When this occurs, we encourage you to utilize our database at Unlimited Purchasing to secure competitive pricing and rapid lead times and unmatched service. Owned and operated by ASAP Semiconductor, we proudly conduct business with AS9120B, ISO 9001:2015, and FAA AC 00-56B accreditation. Furthermore, we also uphold a strict NO CHINA SOURCING pledge and subject much of our offerings to rigorous quality control measures to guarantee only the best for our customers. As you explore our websites, take advantage of our RFQ service to quickly receive competitive quotes for your comparisons, and we promise rapid turnaround times upon receiving requests. If you have any other questions, give us a call or email, and we would be more than happy to help you however we can!


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