Electrical Circuit Breakers

Circuit breakers began to replace fuses in electrical service panels in the 1960s. Whereas fuses could only interrupt circuits one time before needing replacement, circuit breakers can be reused indefinitely simply by resetting their switches. Some large current breakers such as ones used on neighborhood power lines automatically reset to help prevent an extended electrical outage. Circuit breakers come in all shapes, sizes and current ratings from small ones that handle a few volts to ones as large as a truck that can handle over a million volts.

Types of Circuit Breakers

The ones most often found in homes are of the electromagnetic variety. As the current increases, a magnet begins to pull on a spring-loaded switch inside the breaker housing. Once current reaches a preset limit, a switch springs open to cut the current. Breakers designed for very high current loads also must contend with extinguishing a large electrical arc when the contacts inside breakers are separated. They use oil, gases such as sulfur hexafluoride, and vacuum chambers to help achieve this.

Specialty circuit breakers include Ground Fault Circuit Interrupter (GFCI) breakers that help protect circuits installed outdoors and in wet areas such as bathrooms from electrocution hazards. Arc fault circuit breakers detect wiring that is arcing and shuts of the power in milliseconds before an arc can create heat to cause a fire.

According to a professional electrician in Philadelphia, fires caused by arcing in residential homes is often caused by rodents such as mice chewing on wires. In fact, many fires declared to be electrical in origin are suspected of being caused by arcing due to physical damage to the electrical wires inside the walls of homes.

Common Causes of Electrical Breakers Tripping

Circuit overload is usually the cause of tripped circuit breakers. It is when too much current is demanded on an electrical circuit. Most home electrical outlets are on 15 and 20 amp circuits. A typical circuit in a home may have one breaker serving several electrical outlets. Years ago it was uncommon for every electrical connection on a circuit to be in use at the same time. With the prevalence of electrical devices in homes today, it is more common to have more things to plug in than there are plugs available.

The electrical outlet under a window may be on the same circuit as many other outlets. Plugging in something such as an air conditioner will use much of the circuit’s rated power. Plugging in something such as a high-current hair dryer on another outlet connected to the same circuit will likely trip the breaker.

Other causes of circuit breakers tripping are short circuits. This is when the electricity bypasses its normal route and takes a shortcut. It can be due to damaged insulation on the home’s wiring or damage to an appliance connected to a circuit. Short circuits cause explosive sparking and can ignite fires.

Circuit breakers are much more advanced than fuses for protecting the wiring inside homes. They detect and respond to fault conditions in milliseconds, and they can quickly be reset once an electrical fault is corrected. Older homes with fuses should be upgraded to a modern electrical service panel that contains breakers.