Circuit breakers are foundational safety devices that protect our homes from electrical hazards. While resetting a tripped breaker is usually straightforward, understanding why it trips and how it functions can help you maintain a safe electrical system.
Ask This Old House master electrician Heath Eastman shares his expertise on the intricacies of circuit breakers in the video above. Here’s a closer look at the basics of circuit breakers, some common reasons they trip, and how to maintain a secure electrical setup.
Circuit Breakers Basics
Circuit breakers protect people, appliances, and homes from dangerous electrical currents. Acting as the first line of defense, they prevent electrical overloads, short circuits, and other potentially hazardous situations by cutting off power when problems arise.
How Circuit Breakers Work
Circuit breakers monitor the flow of electricity through a circuit. When they detect an issue—like too much current—they cut off the electricity. They don’t always trip instantly after a brief spike, but they will shut down the circuit if the elevated amperage continues beyond typical levels. This delay allows for the temporary spikes that happen when certain devices, like air conditioners or refrigerators, start up.
Types of Circuit Breakers
There are several types of circuit breakers, each targeting specific electrical issues:
- Standard circuit breakers: These protect against basic electrical overloads by shutting off power when too much current flows.
- Ground fault circuit interrupter (GFCI) breakers: GFCI breakers detect where electricity takes an unintended path and trip immediately to prevent electrocution. You’ll commonly see these in bathrooms, kitchens, and outdoor areas.
- Arc fault circuit interrupter (AFCI) breakers: AFCI breakers detect arc faults, which can happen due to damaged or stressed wiring and can lead to electrical fires. These breakers are increasingly required in new homes.
- Combination AFCI/GFCI breakers: These provide protection against both arc and ground faults for comprehensive safety.
Common Reasons for Tripped Circuit Breakers
Understanding why circuit breakers trip can help homeowners identify and address potential electrical issues. Here are the most common reasons:
- Arc faults: Arc faults are dangerous electrical problems resulting from damaged, overheated, or stressed electrical wiring or devices. AFCI breakers can detect the unique electrical signature of an arc fault and shut off the circuit to prevent potential fires. These breakers are increasingly required in modern homes for added safety.
- Ground faults: Ground faults happen when an electrical current takes an unintended path, often through water or a person. GFCI breakers detect these leaks and trip immediately. They’re typically installed in areas where water is present.
- Overloaded circuits: An overloaded circuit happens when too many devices or appliances draw more power than the circuit can safely handle. For example, plugging in multiple high-wattage devices into a single circuit can quickly cause a 15-amp circuit to overload and trip the breaker. Distributing devices across different circuits and limiting the number of plugged-in appliances helps prevent overloads.
- Short circuits: Short circuits occur when a hot wire comes into contact with a neutral wire, causing a sudden surge of current. This can result from loose connections, damaged wires, or faulty appliances. When a short circuit happens, the circuit breaker trips to prevent overheating and potential fires. Regular inspections can help identify and replace damaged wiring that might lead to short circuits.
Circuit Breaker Sizes and Wire Gauge
Matching the right circuit breaker size with the correct wire gauge is required for electrical safety, but using an incorrect combination can lead to overheating and potential hazards:
- 15-amp breakers: Typically used for lighting and light-load circuits, 15-amp breakers require a 14-gauge wire.
- 20-amp breakers: Commonly used for kitchen, bathroom, and appliance circuits, 20-amp breakers require 12-gauge wire. This thicker wire can handle more current and manage the heavier electrical demands of these spaces.
Testing Your Circuit Breakers
Regular testing ensures your circuit breakers are working correctly. Here’s how to test different types:
- AFCI breakers: Use an AFCI tester to simulate an arc fault condition. The breaker should trip immediately, indicating it can detect and respond to arc faults.
- GFCI breakers: Press the test button on a GFCI tester to simulate a ground fault. If the breaker trips, it’s functioning correctly.
- Standard breakers: Testing standard breakers involves overloading the circuit under controlled conditions. Only qualified professionals should perform these tests.
Maintaining Your Circuit Breakers
Proper maintenance helps prevent the issues that cause circuit breakers to trip in the first place. Here’s how to help keep your system in good shape:
- Avoid overloading circuits: Don’t plug too many high-wattage devices into one circuit.
- Keep your electrical panel accessible: Make sure nothing obstructs the panel for quick access in emergencies.
- Inspect any visible wiring: Check for signs of wear, like fraying or discoloration, which can mean underlying problems.
- Schedule regular inspections: Have a licensed electrician assess your system periodically to catch potential safety issues before they happen.
Energy-Efficient Practices To Reduce Circuit Overloads
Implementing these energy-efficient practices can help lessen the risk of overloaded circuits and save on energy costs:
- Add dedicated circuits for major appliances to isolate their electrical consumption.
- Distribute high-wattage devices across different circuits to balance load.
- Upgrade to energy-efficient appliances that draw less power.
- Use LED bulbs instead of incandescent lights for both brightness and efficiency.
When To Call a Professional for Circuit Breaker Issues
While understanding circuit breakers is valuable for homeowners, we recommend professional help in certain situations, such as with:
- Any electrical work beyond simple device replacement.
- Breakers that don’t trip when expected might be faulty.
- Frequent tripping of a specific circuit, which could suggest underlying problems.
- The presence of burning smells or visible damage. This warrants immediate attention.