Can a circuit breaker fail without tripping?

Can a Circuit Breaker Fail Without Tripping?

The short answer is: Yes, a circuit breaker can fail without tripping.  If this happens, you should contact a certified electrician immediately as the problem may exist far from the circuit breaker in the walls of your house.  Don’t get overly discouraged, though, a circuit breaker that has not tripped when the circuit itself appears not to be working may be a relatively inexpensive fix that includes replacing the breaker.  Here’s a tip:  If you find that your circuit is not working but the breaker has not tripped, manually flip the breaker into the off position.  This will offer some protection against possible electrical damage that could occur while you wait for a qualified electrician to arrive and perform a more thorough inspection. 

How to Inspect a Breaker

Inspecting a circuit breaker is relatively easy:  Find your home’s breaker box.  Often the breaker box is in an inconspicuous part of the house, like a basement.  Inside the breaker box will be various black switches, most should be pointed in the same direction (the “on position”) so that power can be freely flowing through the circuit in your home.  If you notice that one of the switches is pointed in a different direction, it is likely that the power to this circuit is off as the circuit breaker has tripped.  Circuit breakers protect people and property from the inherent dangers of electricity.  If there is a problem with the electrical wiring in your home, like an exposed wire that is transmitting electricity outside of the predefined circuitry, then the breaker will detect the excess power being pulled through the electrical system and break it.  This will cut the power to the hazardous area of the circuit until it can be inspected, repaired, and the circuit breaker can be put back in the on position. 

What Happens If A Circuit Breaker Doesn’t Trip?

If the power to one part of a home circuit is not working, but the associated circuit breaker is still showing in the on position, then there could be a problem with the physical characteristics of the circuit breaker, which may have actually tripped but still appears to be in an on position or there could be a problem further downstream from the circuit breaker in the wiring or the other parts of your home’s electrical system. 

What does it mean when a light or an outlet stops working but the breaker hasn’t tripped?

When electricity fails to come to an outlet or light, it means that there is a break in the current.  Typically, this would mean that the circuit breaker (found in the breaker box) or a GFCI outlet has tripped and needs to be reset.  If you have inspected the associated breaker in the breaker box and it has not tripped, then check all of the Ground Fault Circuit Interrupter (GFCI) outlets in your house by testing and resetting.  Especially when the house is older or has had multiple owners (who may have tinkered with the building’s electrical system), there are often scenarios where various outlets or lights have been connected to each other in a sequence (commonly referred to as a “daisy chain”).  When a GFCI outlet has been installed and other outlets have been daisy chained to it, those later outlets are referred to as “downstream outlets” and should be properly labeled as being a GFCI protected outlet.  Many times, however, the downstream outlets have lost the label stating that they are GFCI protected and the current property owner would be unaware that the daisy chain exists.  So, in short, before moving to the next step, check all of the GFCI outlets in your house.  You may be surprised by what you learn!

If you discover that a tripped GFCI outlet was the reason that your outlet or lights stopped working, then congratulations – everything is working as it should!  The likely culprit was an overloaded circuit, like by having too many appliances working off of one circuit, and the GFCI shorted out due to too many amps being pulled through the circuit.  With this new information, you can take note of your circuit’s design and avoid future trips by limiting the amount of power being drawn off the circuit at the same time.  Best practice (and usually local electric code!) would require that you affix a label to the faceplates of the light switches or outlets that have been daisy chained to the GFCI outlet.  These labels can be cheaply bought at any local hardware store or created by yourself by using the words “GFCI protected outlet.”

If the circuit has stopped working and neither the associated circuit breaker nor any tripped GFCI outlets have corrected the issue, then a deeper issue may be to blame.

How to check a single outlet or light switch. 

If only some of the outlets or lights on a circuit have failed, but not all of them, then there is a good chance that the problem is isolated to that part of the circuit.  Many times, a loose wire in an outlet or light switch will cause that part of the circuit to fail.  The rest of the circuit may be working fine, including the circuit breaker that is in the “On”  position, as most structures and almost all modern homes have been wired with AC or Alternating Current.  Unlike DC, or Direct Current, AC wiring easily permits different switches on a circuit to be in an on position while others may be left off.

If you feel comfortable, you should unscrew the faceplates on the electrical switches or electrical outlets that are not working.  Make sure that the power to these switches has been turned off at the breaker box by flipping the associated circuit breaker to the off position!  Remember, just because the outlet or lights are not working, it does not mean that there is no power running to them.  Once you have switched off the power and removed the faceplates to the outlets or switch, make a thorough visual inspection of the wiring.  The wiring to the outlets and switches should be secure.  If you see a loose wire, then carefully reattach it, if possible.  You should also look to make sure that the wires are not touching each other.  

Using a multimeter to check the current in a switch or outlet

Sometimes the issue is with the outlet or light switch itself.  This is a much easier fix as compared to if there is an issue in the wiring in the walls and can be fixed by most homeowners or even a licensed handyman.  An licensed electrician could also be an option for someone who could test, diagnose, and repair a faulty switch or outlet, but that would be probably more expensive than necessary. 

In order to determine if a faulty outlet or light switch is the problem, then you will need a multimeter to determine whether current can pass through the circuit without the switch or outlet:

  1. Turn off the power to the circuit by moving the associated breaker to the off position;
  2. Remove the outlet or switch from the wall by disconnecting all of its wiring  (Pro tip:  Take a picture of the connections from the wall wiring to the outlet or switch before disconnecting them.  This will be a good reference when reconnecting it or installing a new outlet or switch.)
  3. Take a multimeter and place the common receptacle (“COM”) to the negative wire coming from the wall;
  4. Take the multimeter’s live receptacle (usually the red one) and touch it to the positive wire coming from the wall;
  5. If the multimeter is registering current, which is most easily seen in an Ohm’s reading, then the problem is the switch or outlet.  You will need to replace it.   

Installing a new switch or outlet is relatively inexpensive, quick, and easy.  Just attach the ground wires to each other (if applicable), then the negative wires, and finally the positive wires.  REMEMBER to do this all while the power has been cut to the associated circuit by keeping the breaker in the off position.  Honestly, in relation to all other things that could be wrong when an outlet is not working and the breaker has not tripped, this is a relatively good scenario:  The fix is easy, and there is typically minimal danger while the fault outlet or switch is still installed.  

If the wires and the switch or outlet appear properly connected and the outlet or switch has been confirmed to be in working order, then there is likely another (READ: Bigger) issue with the inoperable part of the circuit.  At this point, the likely issue is with the wiring in the walls or with the physical circuit breaker itself.  

Here are a few things that can help a licensed electrician diagnose the cause of a circuit that is not properly working while the circuit breaker is in the on position:

  1. Is the entire circuit working?  If even a part of the circuit is working, then the issue is almost certainly with the wiring on that part of the circuit and not due to a circuit breaker failing without a trip.  
  2. Identify exactly what parts of the circuit are not working.  For this, you will need to have an understanding of what outlets, lights, and hardwired appliances (e.g., security system components) are installed onto the circuit.  Most breaker boxes have some legend or handwritten notes that indicate what breaker is associated with what part of your home’s circuit.  If it is not there or if further details are needed, you can help the electrician’s inspection by figuring this out ahead of time.  This will save you money as the electrician should be able to complete his or her work faster. 
  3. If the whole circuit is not working and the breaker is still in the on position, then there is most likely a problem with the circuit breaker or the wire is severed inside the wall at some point.  Ask yourself is there any reason why the wire may have become severed:
  • Has someone been hanging pictures and possibly driven a nail through electrical wire?
  • Do you have rodents in your house, especially an attic or unfinished basement where there may be exposed electrical wiring?
  • How old is the wiring in the house?  Natural degradation of the wiring and its insulation occurs and even slight events like the slamming of doors or shifting of foundations could shift wiring just enough to break a circuit. 

Testing to see whether a circuit breaker that has failed to trip is faulty is probably a task only suitable for a licensed electrician.  Although it is substantially the same process and conceptually similar to testing a light switch or outlet, in order to test a circuit breaker, the interior of the breaker box itself will need to be accessed.  The breaker box is where virtually all circuitry in your home comes together so that the power to different areas of the home can be cut off.  Circuit breakers are installed to manage the current running through your home’s electrical system so the wiring does not get overloaded and present a hazard to life or property.  It is not advisable to work on a breaker box without being properly trained.  

Through a process of elimination, outlined above, a prudent homeowner can engage with his or her electrical system to determine the likelihood that a circuit breaker failing to trip is at the heart of a home’s electrical problems.  If none of the above has solved the issue, a licensed electrician will undertake the necessary, safe steps to test whether a circuit breaker is not working properly.  The good news is that this is a relatively inexpensive fix when compared to the rewiring of a room or part of your home if the wiring inside the walls is expected to be at fault.  

Remember – Do not work in or around electricity or electrical wires if you are not trained.  The above information can serve as a loose guide to assist property owners in diagnosing and repairing issues that may stem from an outlet that stopped working but the breaker hasn’t tripped.  We recommend using this information so you can understand the steps that a licensed electrician may make to repair your faulty breaker or other issues in your circuit.

Contact us to assist in your Toronto electrical issue!  We have been serving the Greater Toronto Area for nearly ten years and no electrical problem is too big or small!  We believe in an educated client and will walk you through every step of our process so you can understand the electrical repair work that we may be performing on your building and, ultimately, be more satisfied because of it!  

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