Will a Bad Breaker Cause Low Voltage? (7 Causes of Voltage Drop)

breaker test

The electrical system of your home is surprisingly fragile and finicky. The parts and pieces that hold it together and carry electricity appear trustworthy, but they’re prone to problems and issues, just like any other part of your home. Several things can cause unusually low voltage in your home, but is a bad breaker one of them? 

While a bad breaker can cause low voltage in your home, it’s not the most likely culprit. Low voltage can get caused by a wide variety of things, and a faulty circuit breaker is usually very low on the list. However, if your breaker isn’t making a solid connection to the panel box or if it’s overloaded, there’s a chance that it could be the source of your low voltage. 

If you’re experiencing low voltage in your home, several things can cause it, including a bad breaker. Whether you test each of the possible components yourself or hire a professional is up to you, but getting to the root of the problem is essential. 

What Causes Low Voltage in Your Home? 

Poor Wire Quality 

The first and most likely issue is that your home is the victim of poor wiring. Shoddy workmanship or cheap wires can cause your wires to not carry the appropriate amount of voltage than they should. Modern wiring and electrical practices have come a long way, but there’s still the possibility that new and older homes have faulty wiring. 

Low voltage because of bad wiring is most common in older homes. Over time, copper and aluminum wires become corroded or dirty, and their connection to the panel box, outlet, lightbulb, or appliance they’re powering gets impeded. The problem will start with less voltage than normal but can progress into no power. 

It’s also possible that the wires your electrician installed aren’t large enough to power whatever you’re trying to power. Strict code requirements and regulations say how large an electrical wire has to be based on the amperage and wattage it delivers. Wires that are too small are a definite possibility if you have low voltage in your home. 

Long Distances 

Most people don’t realize that electrical wires lose their potency the farther they travel. If the distance from the panel box to its end destination is too far, low voltage can sometimes be the result. The same concept holds for houses in rural areas farther away from the power plants that feed them. 

If you have adequate voltage and power everywhere in your home save for the rooms farthest away from the panel box, there’s a good chance that distance is the culprit. It may be necessary to replace the wire with a slightly larger one to compensate for the long distance. 

Circuit Overload 

Aside from faulty wiring, circuit overload is the most common reason for low voltage in a home. Overload can affect a single circuit or the entire electrical system of your home. When the latter is the case, it’s usually because energy use is at a high point of the day and the houses around you are using lots of power. 

In the case of a single circuit at home, you’re probably trying to power too many things simultaneously on the same circuit. The breaker will trip as a protective measure if the circuit gets too overloaded. A tripped breaker doesn’t mean that the breaker is bad, but it could mean that it and the wire connected are too small.

Imbalance 

Like all things in life, your electrical system requires a healthy balance. If an imbalance is the cause of low voltage, you’ll usually feel the effects throughout your home rather than on a single circuit. Here’s what happens. 

  1. Three wires are coming from the transformer outside your home to the panel box inside your home. 
  2. These three wires are responsible for supplying power to your panel box and the entire house. 
  3. Two of the three wires supply equal amounts of power, and the third is called a neutral regulator. 
  4. If a problem such as corrosion or disconnection occurs with either power wires, the other will compensate to make up for it. 
  5. As a result, any of the breakers receiving power from the faulty wire will have less voltage than the rest of your house. 
  6. This problem is usually evenly distributed throughout your home but can affect one or two circuits. 

Bad Splicing 

Another possible cause of low voltage when it happens on a single circuit is a faulty splice somewhere in the wiring. Splices are especially common in older homes or homes that get remodeled. Rather than running a whole new wire from the panel box, an electrician or homeowner will splice a second wire into the existing wire. If this splice is done incorrectly, the connection won’t be solid, and whatever the wire is powering will have low voltage. 

Ground Faults

Ground faults aren’t unusual, but it is unusual for them to cause low voltage. What usually happens with a ground fault is that electrically drastically and unexpectedly increases. This increase in electricity causes the breaker to trip, which cuts power to whatever it was powering. Ground faults might cause low voltage instead of a tripped breaker in unusual cases, but this isn’t typical. 

A Bad Breaker 

Yes, a bad breaker can cause low voltage somewhere in your home. Like I said before, this is rarely the case, but it is possible. If the breaker isn’t making a solid connection to the panel box or one of the buses in the breaker gets blown, it can result in low voltage. 

What are the Signs of a Bad Breaker? 

There’s bad news and good news about knowing if your breaker is bad or not. The bad news is that it’s usually the last option on the list of possible causes of low voltage. As a result, it should be the last thing that you or your electrician tests. However, the good news is that if you get to this point, there are a few surefire signs of a bad breaker. 

  • Burning Smell 

If you notice a strange burning smell coming from the breaker box, there’s a good chance that the wiring or components of one of the breakers have burned out. 

  • Tripping Lights or Outlets 

Lights that flicker on and off or fade in and out are almost always an indicator of low voltage. If you notice a problem with your lights and a burning smell at the breaker box, a bad breaker is likely the cause. However, jumpy lights don’t always mean a bad breaker. 

  • Circuit Breaker is Hot 

Another surefire sign of a bad breaker is if it’s warm to the touch. By placing your hand on or near each of the breakers in your panel box, you should be able to notice if one of them is warm or hot. 

  • Breaker Trips for No Reason 

The purpose of a breaker is to trip and kill power to a certain point in your home if it gets overloaded with electricity. While this is meant as a protective mechanism, it can also be an inconvenience that depicts a faulty breaker. A good way to test this out is by turning off everything the breaker is powering, save for a few items. If the breaker still trips, it’s likely faulty, or you have a bad wiring connection. 

  • Your Lightbulbs Blow for No Reason

If you’re constantly replacing lightbulbs that give out no apparent reason, a bad breaker is a possible cause. Your breaker may be sending more electricity to the light than is necessary and overloading the bulb. High voltage rather than low is the cause of this problem in your home. 

How to Test a Breaker 

If you suspect that one or multiple breakers are faulty, there’s an easy way to test them. You’ll need a screwdriver, a multimeter, and protective gloves. It will also help if you have electrical experience. Working with live power at a breaker box is extremely dangerous, and you should proceed with extreme caution. 

  1. Unplug all of the appliances or lights powered by the circuit breaker you plan to test. 
  2. Manually test the breaker before removing the panel box cover. To do this, flip the breaker switch to the ON position. If it trips after you do this several times, the breaker is faulty, and you don’t need to conduct a test. 
  3. If it passes this test and you suspect that it’s the cause of low voltage rather than no voltage, proceed to the next steps. 
  4. Remove the screws from the cover of the panel box and set the cover aside. You should now have an unexposed view of the breakers and the box’s internal wiring. 
  5. Flip the suspected breaker to the ON position. 
  6. Turn your digital multimeter on and set it to the voltage setting to read voltage. 
  7. Put the red probe attached to your multimeter against the screw in the breaker box that feeds power to the breaker. You should see a black wire connected to the bottom of the screw. 
  8. Touch the other probe on the multimeter, usually black, to the grounded panel box anywhere on its metal surface. You should see a number pop up on your multimeter, indicating the voltage. If there is no voltage, the breaker is bad, and you need to replace it. If the voltage is substantially less than 110 for a single-pole breaker or 220 for a double pole breaker, your breaker may be low voltage source. 

How to Replace a Circuit Breaker 

If you decide that your breaker is bad and needs to get replaced, this section is for you. Replacing breakers is somewhat dangerous, but only if you don’t turn off the power to your home. Attempting to replace a breaker without turning the power off isn’t recommended and is extremely dangerous. 

  1. Identify the brand and type of breaker that you need to purchase as a replacement. Breakers aren’t universal, which means that every brand has its own style. 
  2. Turn the main power off to your home. The main switch is at the top of your panel box and is usually much larger than the rest. 
  3. Follow the same procedure as above in Step 4 and remove the panel box cover from the panel. 
  4. Locate the bad circuit breaker and remove it from the panel box. You may need to pry it loose with a screwdriver or pliers, but make sure that the power is off to the house. Touching any of the silver components of a live breaker box will result in electrocution. You’ll also have to disconnect the wires that get screwed into the breaker. 
  5.  Install the new breaker in the old one’s place and reconnect the wires accordingly. It might be easier to connect the wires before installing the breaker. 
  6. Put the panel back on the box and turn the power back on. Flip the new breaker to the ON position and perform a test by turning on a device powered by the new circuit. 

Related Questions 

Can a circuit breaker become weak over time? 

Circuit breakers don’t usually become weak over time. It is possible. It’s more likely that the panel box and wires they’re connected to become corroded, resulting in low voltage. 

Can a faulty breaker cause low voltage? 

Faulty breakers usually aren’t the cause of low voltage, but it is possible. If a breaker goes bad, it will usually trip for no reason rather than deliver low voltage in your home. 

Can I test and replace a breaker myself? 

If you have the proper tools and know what you’re doing around electricity, there’s no reason why you can’t test and replace your own breakers. 

Final Thoughts 

Circuit breakers are an integral part of your home’s electrical system, which wouldn’t be complete without them. While circuit breakers are typically stalwart and reliable, they are prone to giving out over time. You must pay close attention to your electrical system and report any anomalies to a professional electrician. They will be able to service your electricity and repair or replace any faulty breakers, wiring, or other components. 

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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.
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