Top Five Electrical Mistakes Made by Homeowners

Doing small electrical jobs around the house by yourself is a great way to save money. At the same time, electrical work is something that must be done with the utmost care for obvious reasons …

common electrical mistakes

Doing small electrical jobs around the house by yourself is a great way to save money. At the same time, electrical work is something that must be done with the utmost care for obvious reasons of safety.

In this article, we discuss the top five electrical mistakes made by homeowners when tackling everyday do-it-yourself home repairs and how to avoid them. For more in-depth discussions and tutorials on DIY electrical projects, please check out

Top Electrical Mistake #1: Mixing 12-Gauge and 14-Gauge Wire on the Same Circuit

Mixing 12-gauge and 14-gauge wire on the same circuit is definitely a big electrical no-no!

To a new DIYer, using two different sizes of wire on the same circuit might seem like a good way to use up extra Romex you have laying around, but it can create confusion for subsequent owners or anyone who comes in to do repairs.

Even though both 12-gauge and 14-gauge wire are rated for use on a 15-amp circuit, best practice is to keep the size of wire consistent throughout the circuit. For example, if you have 12-gauge wire providing power to the box, then you should wire the entire circuit with 12-gauge.

Here’s an example of what not to do (using both white 14-gauge Romex with yellow 12-gauge on the same circuit when installing a light in the basement):

Note that using 14-gauge wire on a 20-amp circuit is against code if the circuit is fed by a 20-amp breaker.

Quick Summary:

  • Use 12-gauge wire for 20-amp circuits
  • Use 14-gauge wire for 15-amp circuits

It should be mentioned that before jumping into any electrical projects you will want to check with your local electrical inspector to make sure you can do electrical work on your home in your city, county, or state.

Top Electrical Mistake #2: Not Making Solid Connections

One of the fundamentals of safe electrical work is solid connections. A solid connection is a safe connection. It also ensures that your lights turn on and your outlets work, but above all, it ensures a safe electrical environment.

Traditional wire nuts do take some skill to install correctly, so if you’re new to electrical work you might not be getting the most secure connections. One missed “pull test” on a wire nut and you could have a faulty situation on your hands.

A tip here is to use WAGO 221 lever nuts.

The transparent housing, resembling a miniature pill organizer, also comprises tiny levers that clamp down on and connect the wires.

To use a lever nut, you simply insert the stripped end of your wires into one of the chambers and then flip down the lever. The housing of the lever nut is clear, so you can see if your wires are fully seated in the chamber.

Lever nuts are a far better connector for DIYers than traditional wire nuts because they make electrical work go faster and create a more consistent and secure connection.

Top Electrical Mistake #3: Not Properly Grounding a Metal Electrical Box

If you’re using a metal electrical box for a do-it-yourself project around the house, it’s imperative to ground the box properly.

If the hot conductor were to short in your metal box, the box would then become a conductor. If you were to touch the box, your body would then become the path of the current that is going (literally) in search of the ground. The danger of this is not to be taken lightly. Having your body be the conductor of stray current can result in injury or even death.

Whenever you have any sort of connections happening in a metal electrical box, whether it’s wires connecting to switches or receptacles, or wires connecting to each other as in a junction box, you should ground the box with a pigtail and a green grounding screw.

This simple measure of grounding a metal electrical box will ensure that the circuit will ground itself out in case of a fault. In other words, it will trip the breaker and keep you and your family safe.

Top Electrical Mistake #4: Not Testing Your Voltage Tester

A non-contact voltage tester is requisite equipment when it comes to electrical work. By holding the voltage tester in proximity to the thing you’re working on, you can see if current is flowing or not.

There is a potential problem with a voltage tester, however. It runs on batteries, which can run down. A dead voltage tester gives no reading, which the user could easily interpret as “no current.”

The voltage tester on the right has the added feature of a light, so that you know when the batteries are still good and you can trust the tester reading.

Even with the added feature of the battery-indicator light, you should test your voltage tester at the moment you go to get a reading to ensure doubt-free results.

This best practice is comprised of three simple steps:

  1. Use the voltage tester on a circuit you know is live to confirm that it is working (picking up voltage).
  2. Use the voltage tester on the circuit you want to work on to confirm that no current is flowing.
  3. Go back to the live circuit from Step 1 to reconfirm that the tester is picking up voltage.

This best practice gives you two validation points, one at the beginning and one at the end, with a test point in the middle.

Testing your non-contact voltage tester in this way will validate that the tester is working correctly so that you can confidently proceed with your electrical project.

Top Electrical Mistake #5: Not Mounting a Support When Installing a Ceiling Light

If you’re thinking about adding a ceiling light to a room, the simplest way to go about it is by installing a circular electrical box that mounts to the drywall. These boxes are typically rated to hold 10-15 pounds. That’s fine if a lightweight lighting instrument is all that will ever be suspended there.

But what happens if you sell the property or time passes and you want to install a ceiling fan?

In order to avoid disaster for subsequent owners or your own future ceiling-fan project, mount a support bracket before installing the electrical box.

The bracket is a telescoping cylinder that you elongate to bite into your ceiling joists. At either end of the cylinder are legs that sit on the backside of the ceiling’s drywall. The electrical box gets secured to the cylinder of the bracket, providing you with a support that will withstand the weight and movement of a ceiling fan or heavy light fixture.

Top Five Electrical Mistakes Made by Homeowners: Conclusion

By observing these tips and best practices, any do-it-yourselfer can avoid the most common electrical mistakes and feel confident that their wiring projects will be done in a way that creates a safer electrical environment in the home.

Please feel free to visit for step-by-step guides on a wide variety of DIY home projects.

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