Residential Circuit Breakers

Circuit breakers are a form of overcurrent protector; they interrupt electrical circuits which receive excess current in order to prevent high heat from resistance which may cause a fire. Overcurrent conditions can happen when too much load is attached to the circuit and power demand becomes too high. Other causes include lightning striking the power company’s wiring or service conductors and sending a power surge through your home’s wiring, and faulty insulation or broken connections allowing electricity to flow through the entire circuit without passing through a load, a condition known as a short circuit.

Frayed wiring insulation that allows the neutral and hot conductors to contact one another is one of the most common causes of residential short circuits. Another hazardous condition causing short circuits is contact between a hot conductor and a conductive material or surface leading to the earth; this is known as a ground fault.

Not only can these conditions be the cause of fires, but any conductive surfaces touching the current will become electrically charged and become part of the circuit. This includes any person or animal touching the surface; in other words, you would be at risk of getting a dangerous and potentially lethal electric shock.

Overcurrent protection in the form of fuses is used in older homes and buildings, but the majority of modern construction houses are equipped with a circuit breaker panel, also known as a service panel. The circuit breakers inside the panel work by setting off a spring which cuts off the electrical supply to the circuit when heat goes beyond a certain point. To restore current to the circuit, the circuit breaker is reset, usually by flipping it back on.

Circuit breakers are rated based on the amount of current, measured in amperage, that they are capable of passing. For a 120 volt circuit, a typical rating for a branch circuit breaker would be 15 to 20 amps, with main disconnect breakers rated from between 100 to 200 amps. If your home has a circuit breaker which goes off repeatedly, never replace it with one of a higher rating. Instead, call an electrician and let them track down the problem and fix it.

For Further Information:

- International Association of Electrical Inspectors
- National Electrical Manufacturers Association
- National Fire Protection Association (Publishers of the National Electrical Code)
- Square D Company (Circuit breaker manufacturer)