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Blown Circuit Breakers

Most of us have encountered a blown circuit breakers before, and if you have not, you will eventually.  Knowing how to change a blown circuit and replace it with a new circuit, or how to reset a tripped circuit, are skills that every homeowner should take the time to know how to perform.

Types of Circuit Breakers

There are three types of circuit breakers used in residential buildings.  They are thermal circuit breakers, magnetic circuit breakers, and thermal magnetic circuit breakers.

Thermal Circuit Breakers have metallic strips that activate a kill switch when temperatures get to a dangerous point.

Magnetic Circuit Breakers have electromagnets that become stronger as electricity grows.  The magnet turns off the circuit when the power coming into it gets too intense. 

Lastly, the Thermal Magnetic Circuit Breakers uses both the previously mentioned methods to protect your home against short-circuits and electrical surges.

Causes of a Tripped or Blown Circuit

If you find yourself fixing tripped or blown circuit breakers often, it might be worth your time to consider why Circuits Trip and Blow in the first place.

There are three typical culprits for Blown or Tripped Circuits in homes: Overloaded Circuit, Ground Fault, or Short Circuit.

Circuit Overload

Probably one of the most common reasons for a tripped circuit breaker is Circuit Overload.

If you try to pull  30 amps of power through a 20 amp circuit, your breaker will trip to prevent overheating.  This might happen because you have too many items running at the same time or it could because something that usually functions correctly is malfunctioning and may be an early warning of much larger and more dangerous problem.

Ground Fault

Ground Fault happens when one of your black wires (hot wire) touches the bare copper wire (or grounding wire) on the side of a metal outlet box. 

Short Circuit

Perhaps the most dangerous cause of a tripped circuit is a short circuit.  This happens when a hot wire (black) touches upon a white (neutral) wire in one of your outlets. 

These two wires touching causes an enormous amount of current and far more heat than the circuit can handle, so it cuts out.

When your circuit trips, take a moment to smell the outlets on that circuit.  Do you smell anything burning?  Do you see any brown or black burn marks on any outlets?  If so, you are experiencing a short circuit and need to repair it as soon as possible.

Resetting a Tripped Circuit Breaker

Many times, it may seem as though a circuit breaker has not tripped, when it has been.  So, even if your breakers all appear to be in the "on" position if something is wrong electrically, you are going to want to methodically go through your entire electrical panel and reset the breakers. 

Remember, resetting the breakers is more than just flipping the switch from the off position to the on position.  Many people fail to realize their circuits might need to be completely off before turning it on again.  So, make sure the switch is fully engaged in its proper position before calling on costly professional help to resolve a very simple problem. 

  1. Firmly push each switch into the off position to make sure it is fully engaged.
  2. Push each switch into the on position.

If the above solution does not work, you may have other problems.  You should review our information on overloading and short circuits, then contact a professional.

Replacing a Blown Circuit Breaker

When a breaker has failed, you will need to change it out.  While it is recommended you hire a licensed and insured professional for this project, a homeowner who has experience and confidence in their electrical abilities can make the necessary repair.

  1. Open your circuit breaker box.
  2. Find the malfunctioning breaker.
  3. Test the circuit breaker and see if it has merely tripped.  You can do this by following our steps above on resetting a tripped circuit breaker.
  4. Breakers often have to be turned all the way off before you can turn them back on, so be sure to do that before going forward.

Once your breaker is back on, you can add devices one at a time.  If the device does not function, then you will not need a voltage tester in the following step.

  • Determine if power is going through the wire by attaching it to the breaker.
  • Deactivate the branch breaker boxes and then flip the big switch located above or below all the other smaller ones.  It is most likely labeled "primary" or something like that.  This is the main breaker, and it has the most amperage of all the other breakers in the panel.
  • Go to each breaker and put it in the off position
  • Look at the outside of the breaker box.  Make sure you do not see any burn marks, rust, or signs of moisture.  If you do, then you need to call a licensed and insured electrician immediately.  Do not try to do this on your own.
  • You might also want to call upon a professional for advice if your box was manufactured by one of the following companies:  Stab-lok, Sylvania, GTE, Kearney, Zinsco, Federal Pioneer, or Federal Pacific Electric. There may be safety issues (a matter that is debated highly among professionals), and you will need more information before going forward on your own.
  • Make sure you have protective gear.  Wear insulated gloves and insulated tools.  Wear shoes with rubber soles, stand on a rubber mat, and use safety glasses.
  • Make sure there is no water or other liquid around the place you are working.  If there is liquid present, call a licensed electrician.  Ensure there is clearance space below, above and to the sides of the front of the electric panel.
  • Remove the screws holding the dead front (or face plate.) Keep in mind the left-hand rule when the panel is opened to prevent injury if an arc flash should occur.
  • Figure out what sort of circuit breaker box have by reading the label on the main power switch.
  • Look (do not touch) at the interior of the panel.  If you see signs of moisture, rust, pests, loose wires, melting, burn marks, wiring with damage, more than one wire under any single screw, strange modifications, debris, or multiple colored wires connecting to each other - do not proceed.  Call a licensed and insured electrician.
  • Take a picture of the old circuit breaker while it is still in place so you can be sure to put the wires back just as they were when you replace the old one with the new one.
  • Go to the faulty breaker and loosen the screws holding the wires there.
  • Remove the breaker from the panel
  • Throw out the old circuit breaker.
  • Make sure your new breaker has the same amperage as the old one.  Once you do, snap the new circuit breaker into the spot the old one was in.
  • Connect the wires to the new one just like they were on the old one.  If needed, take a look at the photo you had taken before you began.
  • Careful not to overly tighten the screws, clamp them back down into place.
  • Put the dead front back into place.  If you lost any of the original screws during the process, be sure to replace them with flat-ended machine screws.  Using wood screws can damage the wires inside the panel.
  • Primary power can now be turned on, then each of the individual breakers.

Troubleshooting Other Circuit Breaker Problems

My circuit breaker will not reset.

  1. Be sure to put the switch into the off position before trying to turn it on. 
  2. Try unplugging all the electrical devices on the circuit and then resetting the switch.  Then plug each item in again one at a time to find out if something is overheating or if you have too many items overloading the circuit.
  3. You might have a short circuit.  Check all the plugs on your tripped circuit for signs of a short circuit (see above) and if this is the case, perform necessary repairs before trying to reset the circuit again.
  4. Check to see if your breaker needs to be replaced (see above.)

Circuit breaker will not reset.

  1. Be sure to put the switch into the off position before trying to turn it on. 
  2. Try unplugging all the electrical devices on the circuit and then resetting the switch.  Then plug each item in again one at a time to find out if something is overheating or if you have too many items overloading the circuit.
  3. You might have a short circuit.  Check all the plugs on your tripped circuit for signs of a short circuit (see above) and if this is the case, perform necessary repairs before trying to reset the circuit again.
  4. Check to see if your breaker needs to be replaced (see above.)

Could something be wired wrong?

Miswiring of the electrical system can cause an issue such as not turning off properly or having something continuing to work even after it is turned off.  Of course, there is also the potential for electric shock.  The shock from miswiring is usually not fatal but can cause harm to people or home appliances.  Miswiring would require the rewiring of circuits and electrical systems in your home.  Most likely you will need to consult a professional to help determine if and where miswiring has occurred in your home.  This will help you meet all local electrical codes and keep you and your family safe.

Overloading?

As we mentioned above, it is possible to overload your circuits by having more things plugged into them than it can safely handle.  Your standard circuit breakers in a residence can only handle about 15 to 20 amps which is enough to run most lights and small appliances.  Larger appliances such as your microwave, stove, dishwater, washer and dryer units will all require a high-rated circuit breaker probably one that has at least a 20-30-amp circuit. 

If your circuits are repeatedly tripping, check for overloading by unplugging your appliances on that circuit and replugging them in one at a time.  If your breaker should be able to handle what you have plugged into it, the problem could be with your appliances.  Check with a professional as soon as possible to determine the nature of your situation as soon as possible.

Is it a short circuit?

Short circuits can cause breakers to trip repeatedly, and if it has been, this is serious as it is a genuine fire hazard.  As we said above, examine your plugs for smells of smoke or signs of char (black or brown residue around the outlets.)  The wiring inside your home could cause this issue, and if so, you want to repair this as soon as possible, either on your own (see above) or with the help of a professional.

Why is my circuit breaker only tripping with certain things plugged in?

It is possible you are drawing too much power through the single circuit and that this one last appliance is the straw that breaks your proverbial camel's back.  However, it is also possible that your one item that is tripping the breaker is not functioning correctly and is overloading the system.  Does it trip other breakers when you plug it into other outlets?  If so, the latter is probably the problem.  If it does not, then perhaps you have already loaded that circuit to its maximum capacity and should refrain from putting more appliances on that circuit.

Why is there a humming coming from my Circuit Breaker box?

A noise of any kind from your breaker box is a sure sign that there may be a problem and it requires an immediate inspection.  It is possible a breaker is taking in too much power and isn't tripping as it should.  It is possible there is a connection problem.  Whatever the reason, a licensed and insured electrician, should be called in to inspect the problem.

Lights in my house blink or fade, is it a circuit problem?

Most likely the problem is with a wire rather than a circuit.  However, it could be a sign the circuit is drawing more power than it can handle.  Solutions involve checking for loose wires, replacing damaged wires, fixing and replacing cords connected to the light. Of course, consulting a licensed and insured electrician about these issues is the best course of action if you are still unsure of where the problem is or how to fix it.

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