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 lax wires and tamp down loose terminals.

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 channel 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.

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.
  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. 

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. Replacing faulty fixtures will require working with potentially dangerous electrical systems. Call a professional if you’re not sure how to address this issue.