Circuit Breakers: How They Work & Signs of Bad Breaker

Electrical circuit breakers protect your home’s lighting fixtures, home electrical appliances, and devices from damage. But more importantly, they protect you and your family. Using a reliable circuit breaker can prevent short-circuiting, which can be harmful and disastrous.

A circuit breaker is an electrical switch designed to protect an electrical circuit from damage caused by an electric overcurrent, overload, or short circuit.

A circuit breaker controls to flow of power to an electrical circuit. A circuit breaker should trip when an overcurrent of 125% or more 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?

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 malfunctioning or you experience frequent disruptions while 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 of the 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 others signs, let us start with the basics of a circuit breaker.

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What is a Circuit Breaker?

Ever been at home doing something, then the power just went off? And when you take a look outside, the streets lights and everyone’s house seems 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.

This mechanism saves you from incurring hefty expenses of buying new switches, bulbs, and electronics. Why?

Because the circuit breaker did what it is meant to do: interrupt abnormal or high current that would otherwise damage all your appliances.

A circuit breaker consists of both fixed and moving contacts. These contacts link to each other to pass on current enabling you to use electricity in the household. This contact point directs electricity supply to each electrical system in the home. These include sockets, lighting, and any other electrical appliances at home.

Types of Circuit Breakers

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

Regardless, here are four of the main types of circuit breakers used in homes:

Single-Pole Circuit Breakers monitor the 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.

Ground Fault Circuit Interrupter Breakers (GFCI) protect against a line-to-ground fault. They are the ones that electricians install in wet rooms such as laundry rooms, kitchens, and bathrooms. They protect you from electrical shocks when a current overload occurs.

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

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

How Circuit Breakers Work?

A circuit breaker mechanism immediately breaks the flow of current supposes it surpasses a certain level. It works similar to a switch that turns off when this current surge comes.

Circuit breakers primarily operate in this manner using these contacts. All of these contact sites form a continuous link when the circuit is closed, allowing current flow. These contacts are also known as electrodes, and the system’s spring pressure connects them.

The arms of the circuit breaker can open and close for system switching and upkeep during regular operation. The only requirement for the circuit breaker to be activated is that pressure has to be applied.

These contacts consist of highly conductive metals, like copper and silver alloy. And the higher the voltage is, the longer the arc distance becomes when the switch goes off. Also, the stronger the current is, the hotter the arc becomes before breaking contact.

What Circuit Breakers Do?

An electrical circuit breaker prevents damage to your appliances and circuit wiring, especially when there is an electrical power surge.

When there is an electrical power surge, the trip coil within the system gets engaged. The breaker then disengages, or “trips,” interrupting the electrical current flow creating an open circuit. Resetting the breaker restores the flow of electricity. In a bad circuit breaker, the breaker will not engage or won’t trip.

As a result, there is no more electrical current flowing within the system. When this occurs, lights, receptacles, and other electrical appliances on the circuit do not work.

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 a 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. 

When this happens, the internal sensor in the circuit breaker heats up and triggers a trip breaking the connection. This ‘trip’ breaks the circuit so that no current flows anymore, so all the appliances go off.

To restore the connection, this off has to be reset manually by switching on the breaker lever.

Short Circuits

A short circuit is another common cause of a circuit breaker that is 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.

Ground Fault Surges

These trip causes are very similar to short circuits. They occur when a heated wire touches a copper ground wire or the metal outlet box that houses the wires connected to the grounding wire.

The heat generated by this connection is far greater than what the circuit can handle. Thus the trip is a lifesaver. It saves all your appliances from overheating or bursting into flames. 

You can also tell a ground fault surge through discoloration of the wires. Ground trips of this nature, you need a professional to fix them fast; otherwise, they may turn fatal.

ARC Faults

An arc fault is a circuit trip exclusive to the AFCI circuit breakers, resulting from the three causes we have named above, plus one more reason. When the system senses that the power is fluctuating, it causes sparkling, also called arching.

This arcing occurs between the wire connections’ contact points and commonly occurs if there is a loose screw terminal in a switch or an outlet.

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 the typical voltage, any current will cause a trip.

Loose Wire Connections

If a part of the circuit has a loose connection, short-circuiting becomes a possibility. Wires can quickly jump from the primary connection and contact others within the metal box. 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. When you touch your metal outlet box housing the wires after a trip and notice some warmness, the likely cause is a loose connection.

The solution to this is relatively straightforward. You should contact a professional electrician to access the connection and tighten the wires and connections accordingly. They must also insulate all the naked wires and earth the metallic casing that houses the wires.

Corroded Wire Connections

Water and moisture do not mix well with electricity and metals. They cause erosion plus the development of rust. Corrosion eats away parts of the wires resulting in an overall deterioration of the wiring and connection tightness.

Tripping is quite often. Due to corroded wires and connections, homeowners in high humidity areas experience more circuit breaker cases.

What are the Signs of a Bad Circuit Breaker?

Makers of efficient and safe circuit breakers design them to trip, so the first sure sign of a faulty breaker is if it does not trip, causing appliances to burn. Here are more signs that can help you identify a bad circuit breaker.

A Burning Smell

Whenever there is a burning smell coming from the circuit breaker box, there is a likelihood the circuit breaker is bad. When you notice this, you must shut off the main power immediately. 

The next step should be to call a professional electrician who will assess the situation and find out the source of the burn.

When the Circuit Panel Feels Hot to Touch

When you touch the electrical panel, it feels hotter than usual. The circuit breakers may be bad. If light switches in the home are hot, you should approach them the same way. You need to switch the main power supply to the house and call a professional immediately.

The electrician will often access the wattage and voltage passing through the system and advise accordingly. The excess heat might result from the unbalanced power capabilities of the wires and connections within the circuit that the circuit breaker cannot handle the frequent trips.

Discolored Wires

When you open the circuit breaker panel box and notice that some wires are discolored or melted, the circuit breaker is faulty.

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

When the Breaker Does Not Stay on Reset Mode

A well-functioning circuit breaker must remain off after it trips. And it should only go on when a person manually turns the breaker’s lever to restore the connection.

But suppose the breaker fosters a reconnect without anyone turning it on; it is best to have it looked at by a professional.

When the Breaker Trips Frequently

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.

In that case, when the electrician comes to assess the situation, they will tell you if the breaker is at fault or the appliance demands more power. Loose connections might also cause this.

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. The solution to this is to have a professional replace it.

Electrical Safety Issues Associated with a Bad Circuit Breaker

A bad circuit breaker can have the following safety concerns in your home:

Electric Fire Outbreaks

The potential of a fire outbreak is the first safety concern that should worry you. When a circuit breaker fails to terminate a circuit when an excessive surge passes through, it might result in an electrical fire. These are some of the most difficult flames to put out.

Water will not put out an electrical fire which adds a dimension of peril to the situation. Cut the power source and, if possible, put out the flames with sand. Assuming it is widespread, flee to safety and ask for assistance as soon as possible.

Destroying Home Appliances

A bad circuit breaker can cost you a lot of money in damaged home appliances. If the surge coming through is beyond what the appliance can handle, the device blows.

And this may also be a source of an electrical fire. If so is the case, the first thing is to unplug the cord from the power supply and extinguish the fire.

Electrocution

Since a short circuit can cause a bad circuit breaker, electrocution is also another concern. For instance, if the short circuit bypasses the part of the connection that has the insulation property. When you touch the plug or wire, you get an electric shock.

Electrical shocks may be a minor thing, but they can also be fatal, resulting in severe burns on contact places and even causing fires.

How to Fix a Bad Circuit Breaker

Fixing a bad circuit breaker is relatively straightforward: replace it.

Regardless, you must never do this independently because there may be far more issues than just the circuit breaker. Sure, it might be the only issue, but it is undoubtedly better safe than sorry.

When you notice any sign that could suggest your circuit breaker is bad, contact a professional electrician. They will assess the situation and restore safety and normal electrical usage within your household. It would be best never to postpone repairing electrical problems like a circuit breaker. The faster you solve it, the better.

Take Away

Unquestionably, a faulty circuit breaker is a ticking time bomb that will cost you money if you do not replace it. Now you know the signs of a defective circuit, the safety issues, and how to fix it.

Power outages can be disastrous and the leading cause of electrical fires, which is why you should hire an expert to inspect the circuit breaker and, if necessary, switch it.

However, before they replace the breaker, they must first determine the source of the trips and correct it. The trips will be just as often, even with a new circuit breaker, if they don’t. To eradicate the problem, a professional should assess the whole system.

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Hubert Miles

I've been conducting home inspections for 17 years. I'm a licensed Home Inspector, Certified Master Inspector (CMI), and FHA 203k Consultant. I started HomeInspectionInsider.com to help people better understand the home inspection process and answer questions about homeownership and home maintenance.
DISCLAIMER: The content published on HomeInspectionInsider.com is not professional advice. You should consult with a licensed professional and check local permit requirements before starting any project.
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