Common Reasons That Cause Tripped Circuit Breakers and Blown Fuses

Within the many electrical systems that we rely on every day, circuit breakers and electrical fuses protect connected electrical equipment and parts from damage. Electricity can be extremely volatile, and faults such as short circuits and overloads can easily damage sensitive components if left uncontrolled. Because of this, having circuit breakers and fuses is extremely important for safety. In this blog, we will discuss how circuit breakers and fuses operate, as well as the common reasons that cause them to trip and blow.

A circuit breaker is a type of electrical switch that is automatically actuated when a fault is detected. When activated, the circuit breaker interrupts the flow of current to impede dangerous voltage that can damage or destroy components. Once activated, the circuit breaker may be reset either manually or automatically. Fuses also protect electrical components from overloads, though they are a one time use “sacrificial device”. Fuses contain a metallic wire or strip that, when too much current flows through it, melts to disrupt the circuit. There are many types of fuses that may be implemented into a system, and these types are chosen based on voltage requirements, response times, breaking capacity, and other application specific factors.

There are many common reasons that a circuit breaker might trip or a fuse might blow, and these include overloaded circuits, short circuits, ground faults, and arc faults. Overloaded circuits are often the main culprit of a constant tripping circuit breaker. Overloaded circuits occur when a circuit exceeds its intended electrical load, typically when too many systems or fixtures are being operated at once. During an overload, the circuit breaker’s internal sensing mechanism begins to increase in temperature and once a specific threshold is reached, a spring activates and breaks the circuit by separating contacts. When a circuit is tripped, it can be manually reset by flipping the breaker lever. If the breaker is tripping because of an overload, energy consumption should be reduced before resetting to avoid reoccurance.

Short circuits are another electrical issue that occurs when hot and neutral wires come into contact with each other. This causes a reduced resistance, resulting in a rapid unimpeded current that activates the breaker. Short circuits may also be caused by a wiring problem within the electrical system as well. To know if a problem is an overload or short circuit, short circuits will often cause the breaker to trip immediately after it is reset.

Ground faults are a type of short circuit that results from hot wires touching ground wires. Ground faults may cause shock if they occur in an area that contains moisture, such as in a kitchen or bathroom, thus warranting caution. As they are a form of short circuit, ground faults cause a spike in current that heats up the breaker, causing it to trip.

Arc faults are a high power discharge that occurs between conductors, and are much less common and more dangerous than the other typers. When a discharge occurs, a great amount of heat is produced that may damage insulation and cause electrical fires. The common causes of arc faults are faulty connections from installation or corrosion. Nowadays, many requirements from the National Electrical Code of the United States have come about that require an arc fault circuit interrupter for protection as standard circuit breakers and fuses to not provide such protection.

When it comes time to begin sourcing the circuit breaker parts and electrical fuses that you need for your next project or operation, ASAP Components has you covered with everything you are searching for. ASAP Components is owned and operated by ASAP Semiconductor, and we can help you find the electronic components and aviation parts that you are searching for, new or obsolete. ASAP Semiconductor is an FAA 00-56B accredited and ISO 9001:2015 certified enterprise. For a quick and competitive quote, email us at or call us at +1-919-348-4040.


August 6, 2019

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