8 Common Electrical Mistakes Homeowners Make

Pink Fiberglass Insulation with Electrical Wires
skhoward / Getty Images

Those DIY shows on television make electrical repairs and improvements seem quite easy. While electrical work is well within the ability of the average homeowner, it's important to do it right. Taking shortcuts could result in electrocution, short circuits, and even fires. In fact, according to the National Electrical Manufacturers Association, 67,800 house fires are caused by electrical problems each year. 

Here's a look at several common mistakes that homeowners make and how to avoid them.

  • 01 of 08

    Not Using a Junction Box

    Electrical wiring junction box
    Iurii Garmash / Getty Images

    Failing to install a junction box is perhaps the biggest mistake homeowners make. Also called an electrical box or connection box, these inexpensive devices protect electrical connections while containing sparks or heat should a short circuit occur. Installing a plastic or steel box adds a step when putting in a new outlet or light fixture, but the actual cost of the box is only a few dollars. Plus, accessible junction boxes are required by code in most areas of the United States. 

  • 02 of 08

    Installing the Box Behind the Drywall

    Electrical junction box
    David Papazian / Getty Images

    Just installing a junction box doesn't guarantee safety. The box must be fitted properly so it's flush with the drywall. Otherwise, combustible materials—like wood—are exposed to potential sparks. If the junction box is recessed too far into the wall, correct the problems with an inexpensive box extension.

  • 03 of 08

    Cutting Wires Too Short

    Electrician trimming wires
    Robert Daly / Getty Images

    Leave enough slack so wires extend at least 3-6 inches from the junction box. To do the job right, you'll need enough wire to strip adequately, connect securely, and fold over within in the box. If you find you've cut wires too short, splice and add an extension. 


    Wires that are too short cause poor connections and create a potentially hazardous situation.

  • 04 of 08

    Overfilling a Junction Box

    junction box with bare copper wires
    GrashAlex / Getty Images

    Cramming too many wires into a junction box is not only dangerous, but it's against the National Electrical Code. Plastic junction boxes are stamped with their approved volume; you may have to calculate the volume of a steel box on your own. Multiply the height, width, and depth of the interior to find the volume to determine if it's the right size for your project.

    Continue to 5 of 8 below.
  • 05 of 08

    Failing to Support a Receptacle or Switch

    Electrical Outlet 170636630
    Getty / PM Images

    Not only do loose receptacles and switches make your home look shoddy, but they also are simply not safe. Buy inexpensive spacers to fix the problem easily.


    Loose receptacles move, which causes the wires to loosen from terminals and arc, a potential fire hazard.

  • 06 of 08

    Mixing Wire Gauges

    three-core electrical cable.
    Oleg83 / Getty Images

    To prevent overloading, use the same gauge wire throughout a circuit. And take care to use the right size wire for the amount of amps in the circuit. Don't go on the look of a wire. Know the amp capacity for each gauge of wire. Contrary to what seems logical, the smaller the gauge number, the thicker the wire. Here is the amp capacity of three common wire gauges.

    • 14 gauge = 15 amps
    • 12 gauge = 20 amps
    • 10 gauge = 30 amps
  • 07 of 08

    Failing to Install a GFCI Outlet

    Safety GFCI protected dual electrical outlet, black power plug

     leah613 / Getty Images

    Ground Fault Circuit Interrupter outlets monitor the amount of power going from the outlet to the appliance or device you're using. If even the slightest variation is detected, the power is cut, thereby preventing electrocution. GFCI outlets are particularly important in areas near water sources:

    • Bathrooms
    • Kitchens
    • Porches and patios
    • Wet bars
    • Garages
    • Outbuildings or sheds
    • Unfinished basements
    • Laundry rooms
  • 08 of 08

    Leaving Cables Unprotected

    Construction of electrical instalations
    Ejla / Getty Images

    Code says electrical cables located in a home's framing should never be left exposed. A conduit is a simple fix that will protect the exposed wiring from damage. Rigid or flexible metal conduit or rigid or flexible nonmetallic conduit is available and ranges in price from around .50 cents to $2 per linear foot. Nonmetallic conduit is easier to work with, but all these conduit types are approved methods of protection in almost all residential settings.

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. The Real Cost of An Electrical Fire. National Electrical Manufacturers Association