How to Fix Light Switch Breaker Overloads

removing a light switch plate

The Spruce / Ana Cadena

If your breakers trip when you turn on your lights, your home’s electrical system is likely suffering from one of the following problems. Since some of these complications can lead to damage or even a fire, it's best not to ignore the issues at hand. You may feel confident attempting some of these tests and fixes yourself, but do not hesitate to hire a professional if you feel uncomfortable at any point during the process.

Loose Wire Connections

The wiring in old switches can come loose and cause grounds and short circuits–both of which can trip your breaker. If you think you may be experiencing this issue, you can take a look under your switch to investigate:

  1. Turn off the power to your switch and remove the cover to inspect the terminal screws.
  2. Check each terminal screw to ensure its tightness.
  3. Reseat any loose wires and tighten down loose terminals.
Light switch cover taken out with screwdriver
The Spruce / Kevin Norris
Screw terminal tightness checked in light switch breaker
The Spruce / Kevin Norris
Loose terminal tightened with screwdriver in light switch breaker
The Spruce / Kevin Norris

Short Circuits

Most short circuits are caused by a live wire touching any of the other two wires in your switch. This contact allows additional current to flow through the circuit and overload your breaker. If you think you may have a short circuit, try the following steps to confirm:

  1. Turn off your switch’s power and remove the cover.
  2. Check each wire to ensure there is no contact.
  3. Look at the wires’ insulation as well—deteriorated insulation can cause shorts and grounding.

Short circuits can also occur in the wiring behind your wall. Addressing this issue will require the expertise of a pro. Ignoring short circuits—especially those behind your wall—can result in fires.

Light switch cover removed with screwdriver
The Spruce / Kevin Norris
Short circuit wires checked on side of light switch breaker
The Spruce / Kevin Norris
Short circuit wire insulation checked behind light switch breaker
The Spruce / Kevin Norris

Bad Switches

Many older light switches have deteriorated wiring that can fail and cause circuit overloads. Here’s how to replace an old or damaged switch:

  1. Cut the power and turn off the breaker that supplies power to your switch. Flip the power main if you’re unsure which breaker connects to your light switch. Use a tester to ensure your work area is powered down.
  2. Remove the faceplate and unscrew the old switch. Set it aside. If it is a 3- or 4-way switch, be sure to mark the common terminal wire, or on a 4-way keep wire pairs marked.
  3. Locate your ground (it's usually a green or bare copper wire) and connect it to the green screw.
  4. Connect the remaining wires. In a single-pole switch, you can connect either wire to either screw. These are located on the opposite side of the switch from the ground. If it is a 3-way switch be sure to place the common wire on the common terminal. For 4-way switches check the wiring diagram that comes with your particular new switch.
Yellow non-contact voltage tester checking power behind light switch
The Spruce / Kevin Norris
Old light switch unscrewed with screwdriver
The Spruce / Kevin Norris
Switch ground located at bottom of bad light switch breaker
The Spruce / Kevin Norris
Remaining wires connected and secured in screw terminal with screwdriver
The Spruce / Kevin Norris

Breaker Trips Due to Ground Fault

Ground faults occur when an energized wire touches a metal frame or housing unit. This diversion redirects the flow of electricity from its normal path and can overload your circuit, causing it to blow. Ground faults can also cause fires, electrical shock, and insulation damage. If you think you have an issue with ground faults, don't attempt to address the problem on your own—have a pro tackle this repair.

Faulty Light Fixtures

Damaged light fixtures are a common source of overloaded breakers. Old fixture wiring can deteriorate and cause grounds, shorts, and ultimately tripped breakers. In most cases, replacing a faulty light fixture is a simple DIY project; however, replacing faulty fixtures will require working with potentially dangerous electrical systems. Call a professional if you’re not sure how to address this issue.

Article Sources
The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Electrical Fires. National Fire Protection Association.

  2. Guide to Ground Fault Sensing. International Association of Electrical Inspectors.