Circuit Breakers: How They Work & Signs of Bad Breaker

Circuit breakers protect your lights, appliances, and devices from electrical damage. They protect you and your family. To avoid harmful short circuits, use a reliable circuit breaker to prevent disasters.

There are several signs to identify a bad circuit breaker. The signs a circuit breaker is bad include:

  • if you have flickering or blinking lights in your home.
  • if light bulbs frequently burn out.
  • If your household appliances are not working correctly or if you often have problems when using them.
  • if your circuit breakers are frequently tripping.
  • if you detect an electrical burning odor emanating from the breaker box.

These are just some signs you will learn in this article, and much more about bad circuit breakers, fixing them, and safety issues. But before we get to the other signs, let us start with the basics of a circuit breaker.

A circuit breaker is a switch that protects electrical circuits from damage due to too much current. It works by stopping the flow of electricity when there is an overload or short circuit.

A circuit breaker controls the flow of power to an electrical circuit. A circuit breaker should trip when a 125% or more overcurrent happens. The National Electric Code (NEC) states that an electrical circuit should operate at 80% amperage capacity.

For instance, a 20 amp breaker should not exceed 16 amps, allowing for increased demand during peak times without tripping the breaker.

But how do you know if a circuit breaker has gone bad?

What is a Circuit Breaker?

Have you ever been at home doing something, and the power just went off? And when you look outside, the street lights and everyone’s house seem to have lights still on! So, the first place to look at is the home electrical panel and see if the main switches have tripped.

Standard breakers consist of both fixed and moving contacts. These contacts connect and allow electricity to flow through them, powering your home. The contact point directs the electricity supply to each electrical circuit in the home. These include sockets, lighting, and any other electrical appliances at home.

40 amp breaker lg

Types of Circuit Breakers

The main difference in the types of standard breakers is their amp rating. Generally, a circuit breaker with a voltage rate below 1000V is a low-voltage circuit breaker.

Regardless, there are different types of modern circuit breakers used in homes:

Standard Circuit Breakers

Single-Pole Circuit Breakers: monitor the electric current of a single wire. They trip when there is an overload, surge, or short current. It consists of one live wire with a neutral wire. Their voltage is 120 volts. 

Double-Pole Circuit Breakers: monitor two wires instead of one. Double-pole breakers will trip if one or both wires are overloaded or shorted out. They deliver between up to 240 volts.

Tandem Breakers: these are used to protect two circuits in homes and businesses from excess current overloads and short circuits. 2-pole breakers can receive two hot wires commonly used to repair double-tapped breakers. Tandem breakers are a type of 2-pole breaker.

Advanced Circuit Breakers

These commercial and residential current devices have current sensors that monitor the electrical power flowing through electrical systems.

Ground Fault Circuit Interrupter Breakers (GFCI): protect against a line-to-ground fault across the hot and neutral wires. They are the ones that electricians install in wet rooms such as laundry rooms, kitchens, and bathrooms. GFCI circuit breakers protect you from electrical shocks when an unsafe level of stray electric current occurs.

Arc Fault Circuit Interrupter Breakers (AFCI): protect against electrical arcs. Arcs usually spark immense heat, thus burning other elements like wood and insulators. AFCI circuit breakers trip when the electrical wiring detects an unsafe level of electrical arcing.

Combination fault circuit Breakers (CAFCI): protect against all types of faults. Electricians now use CAFCI breakers where the local codes require arc and ground-fault protection. CAFCI circuit breakers protect against arc and ground faults.

How Circuit Breakers Work?

Modern circuit breakers are safety devices that stop electricity flow if there’s a short circuit or overload. Inside the circuit breaker are several key components:

  • Actuator mechanism – This is triggered when the breaker needs to trip.
  • Contacts – These separate to break the circuit when the breaker trips.
  • Terminals – Where the wire connections are made.
  • Bimetallic strip – This strip heats up and bends when there is an overload, releasing the lever to trip the breaker.
  • Lever – The actuator trips this switch to break the circuit.

In an overload situation, too many appliances on one circuit draw more current than the breaker is rated for. This heats up the bimetallic strip until it bends enough to release the lever, breaking the circuit.

When there’s a short circuit, a lot of current flows quickly, creating a strong magnetic field. This field pulls the lever and breaks the circuit in only 6 milliseconds.

Modern circuit breakers have two mechanisms. There are two types of protection: one for slow current and one for quick short circuits. When tripped, the lever is released to break the contacts and shut off electricity to the circuit.

What Circuit Breakers Do?

Circuit breakers are safety devices in homes and businesses that stop electricity when there’s too much. Their key purpose is to prevent fires and physical damage by cutting power.

Some common examples of when a circuit breaker may trip:

  • Using too many appliances on one circuit overloads it beyond its rated amperage. For example, blow drying hair on a kitchen outlet while using other major appliances.
  • A short circuit or fault condition that instantly draws a huge rush of current level. Faulty wiring or damaged insulation could cause this.

When a circuit breaker trips, it visually “switches” to an off position and must be reset to restore power. When too much load is too much, the bimetallic strip heats up and bends. This makes the spring-loaded lever release, cutting off power.

During a short circuit, a sudden surge of electricity creates a strong magnetic field in the strip. This immediately pulls the lever and breaks the circuit in only 6 milliseconds. This quick action prevents fires.

As a result, there is no more electrical current flowing within the system. The circuit’s lights, receptacles, and other major appliances do not work when this occurs.

What Causes a Circuit Breaker to Trip?

The answer to this question varies depending on several factors. Nonetheless, here are some of the major causes of circuit breaker tripping:

Overload Circuits

Circuit overloads happen when the drawn amperage exceeds the capacity of the breaker. It occurs when too many appliances or light fixtures are all operating simultaneously. It is crucial to consider factors such as maintenance intervals and ease of maintenance to prevent such overloads.

To keep modern circuit breakers working well, checking and servicing them regularly is important.

When this occurs, the sensor inside the breaker gets hot and causes a trip, disconnecting the circuit. This ‘trip’ breaks the circuit so that no current flows anymore, so all the appliances go off.

This off has to be reset manually by switching on the breaker lever to restore the connection.

Short Circuits

A short circuit is another common cause of a circuit breaker, far more fatal than an overloaded circuit. A short circuit happens when the hot wire touches the neutral wire. When this transpires, the heat becomes immense and causes a trip.

Short-circuiting may be a result of faulty wiring or loose connections. You can quickly identify a short-circuit trip because there will be a burning smell in addition to the discoloration of the wires after the trip.

Faulty Circuit Breaker Symptoms

A faulty circuit breaker may trip often, fail to reset, and emit strange smells or sounds. Other signs may include flickering lights, sparking outlets, and hot load centers. Don’t ignore these symptoms. Get help from an electrician to prevent dangers.

Electrical faults, like ground and arc faults, can be dangerous and cause serious injury, death, or property damage. Faulty wiring can also lead to electrical fires, so it’s important for homeowners to have an experienced inspector check out their home’s wiring system.

Ground Fault Surges

Ground faults are dangerous electrical faults that involve unintended current flow between a hot wire and the ground. They can lead to electric shock and fire hazards if not properly protected. Here are some key points:

  • Cause – Damaged appliance cords, worn insulation on wires, moisture, and damage to electrical devices can all cause hot wires to contact the ground.
  • Danger – Current flows through people if they contact the faulty appliance/wire and ground. It can cause serious shock. It also risks sparking and ignition of fires.
  • Detection – GFCI (ground fault circuit interrupter) outlets and breakers detect current leaks from hot to ground wire.
  • Protection – GFCIs trip quickly (less than 0.1 seconds) when a ground fault is detected, cutting power to prevent harm.
  • Location – Most common in kitchens, bathrooms, and basements where water contact is likely—also near pools, hot tubs, and outdoor outlets.
  • Signs – Appliance sparks, tingling from appliances, GFCI outlets frequently tripping, and circuit breakers tripping can indicate ground faults.
  • Testing – GFCIs should be tested monthly to ensure proper protection. Push the “test” button to confirm the device trips.

ARC Fault Surges

Arc faults are dangerous electrical faults that occur in home wiring and electrical devices. They involve unintended arcs or sparks of electricity that can lead to overheating and fire ignition.

Some key points about arc faults:

  • Cause – Damaged wiring insulation, loose connections, and worn electrical devices can all cause unintended arcs. Environmental factors like moisture and corrosion can also contribute.
  • Danger – The arcs generate intense heat up to 10,000°F. This heat can ignite nearby combustibles, starting electrical fires.
  • Detection – Special AFCI (arc fault circuit interrupter) breakers contain electronics to detect arc faults by their unique current and voltage patterns.
  • Protection – AFCI breakers trip quickly when an arc fault is detected to stop the flow of electricity and extinguish the arc. This prevents fires.
  • Location – Arc faults are common in old wiring, branched circuits, and outlets. Kitchens, bedrooms, and laundry rooms are high-risk areas.
  • Signs – Flickering lights, mild shocks from appliances, and unusual buzzing/crackling noises from outlets may indicate arc faults.

Arc faults are often caused by space heaters, vacuums, and hair dryers that draw a lot of electric power.

breaker test

What Causes a Circuit Breaker to Fail?

Below are some of the things that may instigate a circuit breaker to fail and trip:

Worn-Out Circuit Breakers

If the circuit breaker is old, it may malfunction and cause tripping of the breaker. When these parts wear out, they become overly sensitive. Thus, even with typical voltage, any current will cause a trip. Regularly maintaining and understanding circuit breaker classifications is important for preventing issues.

Loose Wire Connections

Short-circuiting becomes possible if a part of the circuit has a loose connection. Wires in the metal box can easily move and touch other connections. And so this results in a circuit breaker trip.

The trips usually occur when the heat builds up. Then, tiny sparks start traveling between the two contact points. If you feel your metal outlet box after a trip and it’s warm, it might be due to a loose connection.

Corroded Wire Connections

Water and moisture do not mix well with electricity and metals. They cause oxidation of wire connections, causing loose connections and arcing.

What are the Signs of a Bad Circuit Breaker?

Signs Of A Bad Breaker

Bad breaker symptoms might make the lights flicker, trip often, or cause a burning smell. A faulty breaker can make appliances stop working suddenly or cause the circuit to overload. Hire an expert electrician to check and fix a faulty breaker to stay safe.

Efficient and safe circuit breakers are designed to trip. If a breaker does not trip, it isn’t very accurate, and appliances can burn. Here are more signs that can help you identify a bad circuit breaker.

A Burning Smell

If you notice a burning odor, it could be due to the wires overheating. This usually happens when the breaker is old and ineffective. When you notice this, you must immediately shut off the main electric power.

Call a professional electrician who will assess the situation and find out the source of the burning smell.

When the Circuit Breaker Feels Hot to Touch

If the breaker feels hot to touch, it may indicate an overloaded circuit. The circuit breaker may need replacement. If light switches in the home are hot, you should approach them similarly. You need to call a professional electrician immediately.

Discolored Wires

If you see discolored or melted wires when opening the circuit breaker panel box, it’s faulty. Fault conditions can pose risks, especially for big appliances and connected electrical installations. These signs usually mean there is too much electricity or a broken circuit breaker in high-voltage systems.

If you notice this, you must immediately shut down the electric power supply to the home and get a professional electrician to assess the breaker. They will eventually change it and replace the wires that damage them.

Breakers Tripping or Not Staying ON

A functioning circuit breaker will stay off after it trips. It will only go on when someone manually turns the breaker’s lever to restore the connection. If the breaker immediately trips again, the breaker is either bad or there’s an issue with the circuit.

When the Breaker Trips Frequently

This often means there is too much electricity or something broken connected to the power line. When this happens, it’s important to check the devices and fix any problems that come up.

If the circuit breaker is prone to tripping more often than not, it may be faulty. The most common cause of tripping breakers is a loose wire connection at the appliance, the breaker, or along the wire itself.

If the electrical problems are caused by faulty wiring, replacing the breaker won’t fix them. Hire a licensed electrician to inspect and fix damaged wires to protect yourself.

Old Circuit Breakers

An old circuit breaker, as aforementioned, can become overly sensitive. And so, even when the power surge is within the limits a typical breaker can handle, the old one trips. To ensure accuracy and protection, it is best to have a professional replace it in Industrial Applications.

Circuit Breakers FAQs

What are circuit breakers?

Circuit breakers keep electrical circuits safe. They stop the flow of electricity when it’s too much or dangerous. This prevents damage and fires. These devices are important in homes, businesses, and factories. They come in different sizes and types.

How do you fix a breaker that won’t reset?

If a breaker doesn’t reset, first turn off connected devices. Then, wear insulated gear and check for overloads or short circuits to stay safe. Reset the breaker, but consider it a persistent issue if it doesn’t hold.

Can I replace a circuit breaker myself?

You can replace a circuit breaker yourself, but being safe and knowledgeable is important. Hiring a professional electrician is always best.

What is the maximum load on a 15-amp breaker?

The maximum circuit load for a 15-amp breaker is 1440 watts. It is calculated by multiplying the amperage (15A) by the voltage (120V) and 80%. Following the 80% rule keeps things safe and lasts longer, as the electrical code suggests.

Take Away

Circuit breakers are safety devices in electrical panels that cut power in an overcurrent protection scenario. They prevent fires and equipment damage.

Circuit breakers keep circuits safe by stopping power when there’s too much or a short circuit. The components work in conjunction to detect and respond to hazardous overcurrent conditions.


Hubert Miles | Licensed Home Inspector, CMI, CPI

Hubert Miles is a licensed home inspector (RBI# 2556) with more than two decades of experience in inspection and construction. Since 2008, he has been serving South Carolina through his company, Patriot Home Inspections LLC. As a Certified Master Inspector, Hubert is dedicated to providing his expertise in home inspections, repairs, maintenance, and DIY projects.