Electrical Panels: Replacement Signs, Maintenance, and Homeowner Basics

Learn how your electrical panel works and when it's time for an upgrade

Electric Service Panel

Lee Wallender

You may know your electrical panel as that metal panel located in a distant part of your home that you rarely think about it. Then perhaps the power goes out in the kitchen because you turned on the blender. Hitting the reset button on the countertop GFCI outlet doesn't fix the problem. Suddenly you need more information about how to handle your electrical panel box.

Older homes with aging electrical systems may require more frequent visits to the electrical panel box. For newer homes, you may never visit it. Understanding the basics of your home's electrical service panel will keep you safe and your home well-lit and energized. You'll even save money since operating an electrical service panel is crucial to every electrical repair, from replacing an outlet to wiring an entire room for remodeling.

What an Electrical Service Panel Is

The electric service panel is the connection between the external wires coming from the street and the internal wires of your home's electric system.

The service panel is the central distribution point that connects the service wire or service drop—the main wire coming from the outside into the house—to the exit wires that split off and service different parts of the house. These exit wires are called branch circuits or branch wire circuits. 

In single-family residences, the owner of the building owns the electric service panel, not the electric company. Thus, the owner is responsible for all issues related to the electric service panel.

Common Electrical Panel Sizes

There are different types of electrical panel boards that provide 100, 200, or more amps of power to a home. An amp is short for ampere, which is a standard unit of measurement of an electrical current. Homes built between 1950 and 1965 may have these 60-ampere fuse boxes, often with just four fuses. Here's more information on the common sizes, or how many amps of electricity you may need:

  • 100 amps: The average home has 100 amps, but this may be too little for most households.
  • 150 amps: A home that runs multiple appliances at the same time will need 150 amps of electricity in an electrical panel.
  • 200 amps: A home with heavier energy demands or a house that is nearly 2,000 square feet in size may need 200 amps.
  • 400 amps: Large homes that have high-energy needs, or properties with added workshops or outbuildings, will typically require 400 amps to run smoothly.

Electrical Panel Repair and Replacement

Since you own the service panel, you are allowed to work on its interior section for any type of work. The most common fix is to remove and replace a circuit breaker. But if you're expanding your home, adding new appliances, or living in an older home with a panel that has fuses instead of breakers, you'll need an upgrade to a larger panel. But you will know that you need an electrical panel replacement or an upgrade to a larger size if you experience the following problems:

  • Flickering and dimming lights
  • Power surges and tripped breakers
  • A panel that's broken, rusting, sounding odd, or has burn marks
  • A panel that's hot to the touch and emits smoke

Circuit Breaker Service Panels and Fuse Boxes

Electric service panels have a number of different names: fuse box, breaker box, fuse panel, and circuit breaker panel. Today, most homes have what is officially called the electrical service panel, or simply, the service panel. There are two types of electrical panels: single-phase used in homes and three-phase, which is used more so in commercial buildings that require extra power.

A circuit breaker panel is not exactly the same as the fuse box because it has mechanical, toggle-switch circuit breakers, not fuses, but it does perform the same function. The older fuses screw or pull in or out, as opposed to the rocker-style method of installing and removing circuit breakers.

Power comes into the house from a service drop, connects to the service lugs within the service panel, and is split into separate circuits throughout the house. All of your home's power is located in the service panel.

Electrical Service Panel Components

  • Panel door: An outer panel door that swings open
  • Removable cover: Protective cover with spaces for the circuit breaker switches
  • Main breaker: Large switch that shuts off incoming power to all of the circuits
  • Lugs: Metal lugs attached to thick wires that lead out and connect to the service drop
  • Circuit breakers: Removable 15A or 20A switches that control individual electric circuits
  • Spaces: Open or spare spaces on the service panel for creating extra circuits (sometimes, all open spaces will be filled with circuit breakers)
  • Wires: Assortment of wires that run from the circuit breakers to the circuits that service areas of the house


Do not touch the lugs. Even with the main breaker shut off, the lugs are still energized.

Electrical Service Panel Safety Considerations

When the service panel's outer door is closed, the service panel is safe to touch under normal conditions. When the outer door is open and the circuit breaker switches are exposed, the panel is still safe to touch under normal conditions.

It is dangerous to work on an open electrical service panel with both the door and the protective front cover removed. Unlike the shock from a receptacle, which may or may not be fatal, a shock from the service lugs will most certainly be fatal or seriously hurt you.

In the service panel, two black heavy-gauge wires enter the panel from the meter base or a remote disconnect. The main entrance cable can enter the panel from the top, bottom, or even the sides. These are the ends of the service wires that come into your house from the outside. Avoid touching these wires or anything that these wires touch.

With that protective cover removed, shutting off the panel's main circuit breaker switch will not necessarily keep you safe. The main breaker cuts off the power to all of the home's branch circuits, but it does not shut off the power coming into the panel on the utility service lines or to the lugs the lines are connected to.

While it is often easy enough to be cautious of areas in the service panel that your hands touch, also be especially careful of tools that you are holding. The exposed service panel, screwdrivers, wire cutters, wire strippers, pliers, and more are items that can potentially touch parts of the service wires and transmit an electric shock to you.

Installing Additional Circuit Breakers

You can add more circuits and circuit breakers inside your electrical service panel box as long as there are spaces. In many cases, the service panel will have available spaces.

Some older homes may have completely filled out their spaces. In this case, an electrician can install a new, larger service panel box or add a smaller sub-panel and feed it from the main panel. This will require you to move older circuits to the sub-panel to make space for the feeder breaker.


An easy solution to a service panel that's full of circuit breakers and has no available slots: tandem circuit breakers. Tandem circuit breakers fit in the same-size slot as a normal breaker but can serve two separate circuits.

Generally, you can determine if there are more spaces by looking at the metal knock-outs on the panel itself. Any space that is not knocked out should be available for the insertion of another circuit breaker, but this is not always the case. Remove the cover to see how many open spaces are available.

Do-It-Yourself Electrical Panel Repairs and Remodels

Homeowners are allowed to work on the service panel, but many choose to avoid this for safety reasons. Most homeowners only have the experience of opening the outer door of the electrical service panel to flip on a disabled circuit breaker.

Many seasoned do-it-yourself homeowners still choose to call in an electrician when it comes to any work that involves removing the protective front cover and handling the electrical panel wiring. An electrical panel price will vary based on the size needed and the work that needs to be done. As a ballpark, electrical panels cost about $1,100 to upgrade or replace and $1,300 to install.

Where to Find the Electric Service Panel

By its nature, the main service panel is usually kept away from the main household activities. Likely locations:


The garage often hosts the electric service panel because it is covered, accessible, and close to other services. Look on the wall adjacent to the house.


If the home has a basement, chances are good that the electric service panel will be located there. Look on an exterior wall.


If the electric service panel is located in a hallway, it will usually be one that leads to the garage or outdoors rather than near the main entrance.

Pantry or Closet

The electric service panel may be tucked away in a built-in pantry adjacent to the kitchen or in a utility closet.


Look outside for the service panel, usually in a covered location. While not typical, a service panel may be found on the outside part of an exterior wall, especially in the case of older fuse boxes.


One way to find your electrical service panel is to first go outside and locate the service drop and service head on your roof. The service panel should be directly below, at one of the home's lower levels. For buried power lines, the line will start at the street and connect to the home near the front or side of the home.

  • What is the difference between a breaker box and an electrical panel?

    These two terms refer to the same thing. When you open a breaker box or electrical panel, you will find the breaker switches.

  • How long do electrical panels last?

    An electrical panel will last between 25 to 40 years, after which it will show wear and need replacement.

  • How many circuits can be in a 200 amp panel?

    Though the number can vary, there will typically be between 40 and 60 slots for circuits in a 200 amp panel.

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  1. Electrical Repair Work. HomeAdvisor.com.