What are Electrical Panels? A Comprehensive Guide

Most people have heard of electrical panels, but few know what are electrical panels and how they work. Electrical panels may seem complex, but they operate on simple principles that are easy to grasp.

An electrical panel is a metal box that holds your home’s circuit breakers. You can also call it a breaker box or breaker panel. Modern homes have circuits that control the power to portions of the house. Circuit breakers “trip” when needed and cut off power to a specific circuit as a safety measure.

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Home electrical and breaker panels may seem complicated but easy to understand. Take the time to learn the basics. We will explore electrical panels. We’ll cover how they work, the various types, and how to locate your breaker panel at home. Additionally, we’ll address other common questions about breaker boxes.

What Are Electrical Panels? A Comprehensive Guide

The Basics of Electrical Panels

If you own a home or live in one, it’s important to understand electrical panels. They help keep you safe and make things easier. It’s important to locate the breaker box in your home during an emergency. This allows you to turn off power to the affected circuits.

Moreover, your breaker will trip, and you’ll need to reset it and restore power to the circuit. Learn where your home’s electrical panel is and how it works to make things smoother. It’s also good to know how equipment in your home works for any repair work you need.

What is an Electrical Panel?

A modern home has circuits that control electricity in specific areas of the house. A single circuit can power many rooms, but each room in a house has its own circuit. Large appliances have dedicated circuits.

An electrical panel is a steel box that houses circuit breakers. The meter sends power to the main breaker panel, dividing it into separate circuits. Each circuit has its circuit breaker. There are various sizes and types of breaker panels, like main panels and sub-panels. We’ll discuss them in more detail later.

The central panel breakers keep your home’s electrical wiring safe. They separate it from the meter. If a breaker senses a dangerous electrical problem, it shuts off power to that circuit. The electrical panels in your home’s system operate similarly, but someone places them.

Electric Panels, Safety, and Electrical Codes

Electric panels regulate the electrical load and provide a place to disconnect power in an emergency. Electric panels can be extremely dangerous and lead to house fires when improperly maintained or overloaded electrical equipment.

The circuit breakers will trip in the event of an electrical overload. This safety feature prevents electrical fires. If a circuit breaker trips, it doesn’t always mean something major is wrong. Still, it’s important to have a professional electrician check it out.

Many older homes have faulty wiring that isn’t up to current electrical codes. Home inspections are important for homeowners and prospective buyers to ensure people’s safety.

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The Components of an Electrical Panel

Opening the metal door of an electrical panel reveals a jumble of wires, bars, and switches. But every piece has a specific purpose. The entire system cannot function without all the components. Below, we’ll go over the main parts that you’ll see in a typical home electrical panel:

  • Breaker Box – The breaker box is a metal enclosure that holds all the described components. Breaker boxes are mounted on the wall and have a single door on the front. The top has a big opening for the wires. There are popouts on the top, bottom, and sides for branch circuits to go out.
  • Source Wires – Source wires are the wires that come from the meter into the breaker box from the top. There are three source wires: two hot and one neutral wire. The two hot wires connect to the main switch. The neutral wire connects to the neutral busbar.
  • Main Disconnect Switch – The main disconnect switch connects the two hot source wires. Then, it goes to the hot busbars. Near the top of the breaker box, you can find the main breaker for the breaker panel. The whole electrical panel loses power if the main switch trips or you turn it off.
  • Hot Busbars – The hot busbars are two bars running down the breaker panel’s center. The hot source wires connect to the hot busbars. This supplies power to the entire load center and any after-branch circuits. Circuit breakers run along the hot busbars.
  • Neutral Busbar – The neutral busbar connects the primary neutral wire to all the neutral wires from branches. The neutral busbar’s location varies in each breaker box. It runs parallel to the hot busbars or off to the side when combined with the grounding busbar.
  • Grounding Busbar – The grounding busbar connects the wires from branch circuits for grounding. It connects to the central grounding electrode (grounding rod). You can find the grounding busbar near the bottom of the breaker box or parallel to the hot busbars. It is also connected to the neutral busbar on the main breaker.
  • Circuit Breakers – Circuit breakers are switches in the breaker box that run along the hot busbars. The hot busbars are the primary power source. The breakers stand between them and the branch circuits. Each branch circuit gets a dedicated circuit breaker. There are three main types of breakers: standard, GFCI, and AFCI.
  • Branch Circuit Wires – The wires in your home form circuits. These wires include neutral, ground, and hot wires. Most 120V circuits have three wires: hot (black), neutral (white), and ground (bare copper or green). 240V circuits may have three or four wires. These are hot L1 (black), hot L2 (red), neutral (white, sometimes not there), and ground (copper or green). Adding extra wires to a circuit can make it more complicated, especially if it is complex.

How Do Electrical Panels Work?

Electrical services may seem complex, but they are easy to understand once you grasp electrical systems. Your home’s electrical system has circuits. Electricity powers appliances and outlets and then returns to complete the circuit.

The main electrical panel boxes get power from the electrical utility’s incoming power wire. The utility’s wires bring a high voltage current to your home. It goes through a transformer to lower the voltage. Then it goes through the electric meter and enters your home. A sub-panel works similarly but gets power from the main electrical panel instead of source wires.

The current runs from the hot source wires to the main disconnect switch. The main disconnect switch is the big breaker at the top of the breaker box. It shuts off the whole panel. Power then reaches the two hot busbars running down the center of the electrical panel.

Electricity flows from the hot busbars to the hot wires in the power branch circuits. The power branch circuits exit from the sides of the electrical panel. We place circuit breakers on the hot busbars to turn off each branch circuit. You can turn off circuit breakers to stop power, but they trip if there’s a power surge or too much current.

Branch circuits can power appliances, outlets, and lights in a home. The current then goes back to the electrical panel to complete the circuit. Power returns through the neutral wires, at least in an unbalanced system. The neutral wires connect to the neutral busbar. It can also connect to the neutral/ground busbar in a main electrical panel.

Electrical panel boxes are the hubs for your home’s electrical system. Electricity comes into the breaker panel from the utility. It then divides into circuits to power your home. Finally, it goes back to complete the circuit. The main switch and circuit breakers keep your home safe and let you control the electricity.

What Are Electrical Panels? A Comprehensive Guide

Different Types of Electrical Panels

Electrical panels control the electrical distribution in buildings. Let’s now explore the various types of panels you might come across. In general, there are four types of electric panels:

  • Main breaker panel
  • Main lug panel
  • Sub-panels
  • Transfer switches

Main Breaker Panel

The main breaker panel is the primary electrical service panel in most homes. The main source of electricity in your home is the meter that connects to your house. From there, it splits into smaller circuits to power everything. 

Main breaker panels have hot source wires from the utility. These wires usually enter from the top. The switch on top of the breaker box controls your house’s power. The hot source wires then connect to the hot busbars running down the center of the enclosure.

Circuit breakers connect branch circuits to the hot busbars to keep things safe. They do this at the connecting point. The breaker senses a sudden rise in current from a fault, power surge, or short circuit. It then trips and stops the power to that circuit.

Both neutral and grounding use one busbar in the main breaker panel. It does not have separate busbars for each. The neutral/grounding busbar connects all ground and neutral wires from branch circuits. The grounding rod and the neutral/grounding busbar connect in some areas.

Main Lug Panels

The main lug panels are the same as the main breaker panels but don’t have a main disconnect switch at the top. Instead, the hot source lines run to a lug connector.

It is common for lug panels to act as sub-panels in many residential electrical systems. Often, the main disconnect switch for a lug panel is at the meter or main panel.

Like main breaker panels, main lug panels have hot busbars in the center of the enclosure. The hot busbars split into branch circuits. Each has a circuit breaker for emergencies. The natural and grounding busbars on a lug panel are not combined like on subpanels.

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Subpanels are smaller electric panels found downstream from the residence’s main breaker box. For big houses far from the main panel, they serve as a second electrical hub for extra circuits. Most sub-panels are lug panels and do not have a main disconnect switch on the panel.

The main breaker panel determines how many sub-panels a house can have. Like a branch circuit, the sub-panels get power from the main breaker panel. 

Sub-panels operate to the main breaker or lug panel. The subpanel’s source wires are from the main breaker box, not the electric utility’s meter. In a sub-panel, the neutral and grounding busbars must be separate bars. In the main electrical panel, you cannot combine them, like the neutral/grounding busbar.

Transfer Switches

Transfer switches are a special kind of sub-panel. When your home has a backup power source connected to the electrical system, you use them. Many backup power sources, like standby and whole-house generators, need a transfer switch to connect to your home.

You can find transfer switches near your home’s main breaker panel. They let you switch your home from utility power to a backup power source. There are two main types of transfer switches:

  • Manual – With a manual transfer switch, you must turn on your generator and move the switch to the “on” position. Switching to backup power with a manual transfer switch saves money but requires more manual work.
  • Automatic – Automatic transfer switches are more advanced than manual ones. They are usually pricier. When the power goes out, a switch turns on your generator and switches your home’s power source. You don’t have to do anything.

Differences Between a Fuse Box and an Electrical Panel

Control panels can be confusing due to terminology and small differences between systems. You often hear about fuse boxes and electrical panels, but what’s the difference?

Electricity flows through a fuse box and an electrical panel almost. But, there is one important difference. In an emergency, fuse boxes cut power on branch circuits using fuses. Electric panels use circuit breakers.

Fuse boxes have screw-in fuses along the hot busbars. The fuses will break and stop the power if the current is too high. This can happen from a power surge or a short circuit. Fuses are single-use, so when one burns out, you must replace it. Fuse boxes use older technology and are uncommon in residential buildings today. 

Electrical control panels have circuit breakers on the hot busbars. These breakers trip when the current exceeds their rating, caused by a surge or short. You can reuse circuit breakers by switching them back to the “on” position to restore power. Modern homes usually have electric panels. These panels help control the electrical systems. They are easy to use and have advanced safety technology.

Electrical Panel Ratings and What They Mean

Electric panels vary in size and amp ratings to handle electrical power. Different sizes of breaker panels, including ones for homes, meet different electrical needs. You can also use these panels to add more circuits for specific power needs in homes and buildings.

The amperage rating on the breaker box informs you of the greatest amount of current that can be drawn. It is always better to have a breaker box rated for more amps than you need over one too small. Generally, you should draw no more than 80% of your panel’s capacity.

The size of your electrical panel depends on how much electricity your house needs. Most homes have limited amp service from the utility company, so you can only draw a certain amount of power.

Another consideration is the number of circuit breaker slots on the electrical panel. It’s best to get a panel with extra slots for expansion, even if you don’t need them. The spaces in a residential home breaker panel can range from 12 to 60+. The number of slots in a breaker panel depends on the manufacturer. Here are some standard configurations.

Breaker Panel SizeNumber of Circuit Breaker Slots/Spaces
100 amp20
125 amp25
150 amp30
200 amp40

Single-pole 120V breakers only need one slot on the panel. Double-pole 240V breakers need two slots. Tandem breakers join two 120V circuits in one slot, which is helpful for small electric panels.

How to Locate an Electrical Panel in a Home

If you have electrical work or want to learn about your house, you may wonder where to find the electrical panel. Locating the main electrical panel in a home is pretty straightforward.

  1. Check Common Locations – Electrical panels are indoors but can be on your house’s side. The main electrical panels are in basements, utility rooms, laundry rooms, or closets. It’s on the first floor in houses with many levels.
  1. Look for a Small Access Door – Breaker boxes are gray metal unless painted over to blend in with the decor. When installed in a finished wall, you should see a small access door swing open to the side.
  1. Check Your Home’s Paperwork – To find the electrical panel, check your home’s blueprints or inspection report
  1. Consult an Electrician – If you can’t figure it out, consult an electrician. They’ll help you locate your home’s electrical panel. If you know what you’re looking for and use the information above, you should be able to find it. But consulting an electrician is also an option.

How Long Do Electrical Panels Last?

You need to replace most modern electrical control panels every 25 to 40 years. As equipment gets older, it gathers some rust and starts to deteriorate. So, replacing your electrical panel at the recommended times is a good idea. If your home still has a fuse box instead of an electrical panel, replacing it with a modern breaker box is best.

Turn off the incoming power immediately if you see scorch marks, a burning smell, water damage, or rust in your breaker box. Then, call an electrician. The signs may say serious problems or the need to replace your electrical panel sooner. It’s important to address them.

What are Electrical Panels FAQs

What is in an electrical panel?

Electrical panels, or breaker boxes, distribute power in a building. The main parts are a main breaker, safety circuit breakers, bus bars, neutral and grounding buses, wiring, and circuit control labels. Caution is key; consult a professional for modifications or repairs.

Is an electrical panel the same as a breaker box?

The breaker box is an electrical panel housing both main and individual circuit breakers. Its purpose is to safeguard specific electrical circuits. Although these terms are used interchangeably, they play a vital role in the electrical system of a building.

What is the purpose of electrical panels?

Electrical panels, known as breaker boxes, distribute electricity in buildings. They protect electrical circuits from overloads, serve as central hubs for electricity distribution, offer organizations easy maintenance access, and help upgrades.

What are the four types of electrical panels?

Various types of electrical panels cater to different requirements. The main breaker panel governs the power distribution, while the main lug panels act as secondary sources. Sub-panels provide localized power. Transfer switches ensure seamless transitions between utility and generator power.

Final Thoughts

Upon closer inspection, one can demystify electrical panels that may seem daunting. At the panel’s top, hot source wires enter and connect to the main disconnect breaker switch. They connect to the hot busbars at the center of the circuit breaker panel. This helps distribute electricity to different circuits.

These are important electrical components that make sure the electrical current flows. These parts meet safety requirements set by insurance companies. They include extra circuits for power. Have a qualified electrician install and maintain these panels for the best performance and safety.

A licensed electrician manages the electrical panel. Circuit breakers are housed along the hot busbars. The breakers in your home control the power. They ensure it is distributed safely to your appliances, outlets, lights, and sub-panels. The panel is a load center that protects electrical devices and components with safety devices in a box.

Hire an Electrician

Get FREE estimates from licensed electricians in your area today. Whether you need to replace an outlet, hang a ceiling fan, a new electrical panel, or repair wiring, We Can Help!

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Hubert Miles | Licensed Home Inspector, CMI, CPI

Hubert Miles is a licensed home inspector (RBI# 2556) with more than two decades of experience in inspection and construction. Since 2008, he has been serving South Carolina through his company, Patriot Home Inspections LLC. As a Certified Master Inspector, Hubert is dedicated to providing his expertise in home inspections, repairs, maintenance, and DIY projects.