How to Avoid Common Mistakes When Installing a Subpanel

How to Avoid Common Mistakes When Installing a Subpanel

Installing a new subpanel in your home can be a complex project, but also extremely rewarding if done properly. However, there are some common mistakes that are easy to make if you are not careful. In this guide, I will walk through the subpanel installation process step-by-step, pointing out the most common errors and how to avoid them.

Choosing the Right Subpanel Size and Location

The first step is choosing the right subpanel size and optimal location in your home.

Determining the Correct Subpanel Size

Picking the Right Location

Hiring a Licensed Electrician

Installing a subpanel is complex and potentially dangerous. Only a licensed electrician should take on this project.

Hiring a pro is strongly recommended over DIY for safety. The small upfront cost is well worth it.

Using the Proper Wire Size

Using wire that is too small is a common DIY subpanel mistake. This can cause voltage drop, overheating, and potential fires.

Installing Appropriate Breakers

Breakers in the new subpanel must be compatible and appropriately sized.

Providing Sufficient Grounding and Bonding

Proper grounding and bonding prevents electrocution and shock by providing a safe path for errant electrical current.

Getting Necessary Permits

Most jurisdictions require permits and inspections for subpanel installation:

Skipping permits and inspections is extremely dangerous and risks electrocution hazards in the home. Do it legally.


Installing a subpanel is not a project for amateurs. Mistakes can destroy property, cause injuries, start electrical fires, and even kill.

Hire only licensed professionals, get proper permits, use sufficiently large components, and follow safety procedures. The process is complex, but perfectly safe when done correctly. Spending the small amount upfront to have it done properly avoids huge risks down the road.