In a typical modern electrical system, the panel’s circuit breakers serve as the first line of defense. If a device draws too much power, it’s the circuit breaker’s job to cut the electric flow to prevent a potential hazard. Given how much rides on your home’s circuit breakers working properly, you would be right to wonder whether they can fail.
The quick answer is yes, circuit breakers can and do go bad. It’s beneficial for homeowners to understand what circuits are, what electrical overloads are, how circuit breakers work, why breakers can go bad, and what you can do about it.
What Is an Electrical Circuit?
Outlets and switches are grouped into circuits. Each circuit has a maximum amperage it can handle, which represents the maximum flow of power that can pass through it. A bedroom typically has a single circuit of 15 to 20 amps that serves both overhead lighting and all the outlets.
Some devices require a significant amount of amperage, meaning they need a substantial amount of electricity in a short period. For example, your home’s clothes dryer and air conditioner are notoriously high-amperage devices. A high-load appliance, such as the HVAC, might require as much as a 60-amp circuit. Major appliances almost always have a dedicated circuit.
A kitchen will have multiple circuits. It often has a dedicated circuit for lighting, two circuits for plugging in countertop appliances, and a dedicated circuit for each major appliance, such as the stove and refrigerator.
What Is an Electrical Overload?
An overload occurs when more power is demanded than the circuit is designed to handle. If too much power runs through the circuit, it could melt the wires in the wall and create a fire hazard. Likewise, overloads can damage expensive systems, such as appliances and computers.
Overloads happen for many reasons. A device with a failing power supply might draw more electricity than it’s rated for. Additionally, a surge from outside the circuit could overload the system, such as a lightning strike or a momentary issue with the local electrical grid. All overloads are potentially dangerous.
Running too many items on a single circuit will result in an overloaded circuit. Older homes might not have a dedicated circuit for things like a dishwasher. If the outlets for the dishwasher and microwave are on the same circuit, running both simultaneously could cause the circuit to overload. Similarly, in a bedroom, if you’re running a humidifier, charging devices, and operating a vacuum on the same circuit, you could overload it.
Power strips and extension cords are another common cause of overloaded circuits. Older homes often lack sufficient outlets to accommodate these needs, so we use power strips to plug in additional devices. As we accumulate devices, such as smart TVs, computers, smart speakers, and mobile devices, our demand for power increases. The situation worsens if you add a space heater or fan.
How a Circuit Breaker Works
The solution in nearly all modern systems is the circuit breaker. There are three types of circuit breakers: thermal, magnetic, and thermal-magnetic
A thermal circuit breaker is typically bimetallic, meaning it utilizes two different metals. The idea behind the bimetallic strip principle is that different metals heat at different rates. If the strip is heated, it bends at a specific rate and in an expected direction. Likewise, it cools and bends in the opposite direction.
Electricity heats the bimetallic strip. If there is too much thermal expansion in the strip, typically a sign of an electrical overload, then the system breaks the circuit. This effectively shuts off the power by breaking the available electrical path, protecting your home’s systems from overloads.
A magnetic breaker relies on an electromagnetic device to detect when the flow of electricity exceeds the circuit’s capacity. A thermal-magnetic breaker relies on both thermal and magnetic technologies to detect an overload.
Why Circuit Breakers Go Bad
It is worth noting that circuit breakers are sacrificial components. They exist so that they can die rather than compromise more expensive parts of your home’s electrical system. No circuit breaker is meant to last forever.
However, that doesn’t mean that it’s a good thing for a breaker to go. A circuit breaker can fail prematurely for several reasons. The physical stress of repeatedly tripping does small amounts of damage to a breaker. This damage adds up. If your home has a circuit that regularly trips, the odds are high that the associated breaker will fail sooner rather than later.
The bimetallic design of a circuit breaker also exposes it to corrosion. If your home’s electrical panel is in a high-humidity area, it’s more likely to corrode. This causes the springy strip to lose its elasticity, making it harder for you to reset the breaker.
Contacts inside the breaker can also degrade. If the breaker has tripped repeatedly, its metallic properties will change. Breakers briefly arc in many instances. Arcing can damage the materials and increase resistance within the breaker. This effectively lowers the breaker’s rating, causing it to trip sooner.
Metal and heat fatigue also occur over time even if the breaker never trips. The heat from the electricity slowly changes the metal, not unlike the discoloration you might see around a welded part. As this degradation occurs, the breaker loses some of its resistance, making it more likely to trip. Most circuit breakers typically last between 20 and 30 years under normal operating conditions.
Common Failure Conditions and Their Signs
The most common failure is that the breaker turns off without any other signs of trouble. If this repeatedly happens, you may want to assess whether you’re running too much load on the circuit. For example, plugging power tools into outdoor sockets that were only meant for Christmas lights could trip a breaker.
In many cases, the simplest solution is to stop running such aggressive loads on specific circuits. If you require those loads, then talk with one of our electricians about rewiring the circuit and adding a higher-capacity breaker.
One of the scarier failure conditions is arcing. In this scenario, electricity is trying to jump between the contacts inside the breaker. You might notice buzzing or clicking sounds coming from the electrical panel. In some extreme cases, the whole breaker could short-circuit. This is a serious hazard, and you should consult one of our electricians to address it.
Overheating is another cause of failure. A common sign is the smell of melted plastic or ozone near the electrical panel. Bear in mind, the breaker could fail and still complete the circuit. This isn’t good because the whole purpose of a breaker is to stop electrical flow.
Smaller signs include flickering lights and loss of power on the circuit. Inconsistent breaker trips are also a sign of trouble.
Get Help From the Pros
Spark Daddy performs electrical installations, repairs, and maintenance for the people of Ballwin, Pacific, and throughout the Greater St. Louis area. We work on everything from minor outlet repairs to generator and EV charger installations. Our goal is to ensure that your home’s electrical system operates as safely, efficiently, and conveniently as possible. We are a local business that’s licensed, bonded, and insured.
If you’re worried about a circuit breaker in your Ballwin home, contact Spark Daddy right away.
