What is an Electrical Sub Panel?

circuit breaker / electrical sub panelThe Important Role Sub Panels Play

Electrical panels are the backbone of any building’s electrical system. They manage and distribute electricity throughout the structure, ensuring that power flows smoothly to where it is needed.

Among these panels, the electrical main panel and electrical sub panels play distinct yet interconnected roles.

This article will dive into what an electrical sub panel is, how it works, and why it might be necessary for your home or business.

What’s the Main Panel?

The main panel is the central hub for all your electrical needs. It’s the primary entry point for electricity coming from the power company.

Think of it as the gatekeeper of your home’s electrical system. This panel houses the main circuit breaker, which can cut off electricity to the entire house, offering protection during electrical surges and maintenance. Often referred to as the service entrance panel, it’s crucial for controlling the overall electrical flow and ensuring safety.

The main panel’s job is to distribute power from the utility company to various circuits in your home. Each circuit is protected by a breaker that can shut off power to that circuit in the event of an overload or short circuit. This prevents electrical fires and other hazards, making the main panel an essential component of any electrical system.

How Does a Electrical Sub Panel Work?

An electrical sub panel is essentially a smaller version of the main panel. It acts as a secondary breaker box, distributing power to specific areas or appliances.

Just like the main panel, it contains fuses and circuit breakers that protect against power surges. However, its primary function is to offer a more organized way to manage electricity in different parts of your property, especially if you have significant electrical needs spread out over a large area.

Sub panels are fed by the main panel through a feeder breaker. This setup allows the sub panel to distribute power to circuits in a specific area without overloading the main panel. Sub panels are often used in garages, workshops, or additions to a home where the electrical demand is higher.

Differences Between an Electrical Sub Panel and Main Panel

The main panel serves as the primary connection to the power supply, while the sub panel gets its power from the main panel.

The main panel is directly connected to the building’s entrance point for electricity, making it the primary control center. Sub panels, on the other hand, feed off the main panel, providing a more localized control. This setup not only helps in organizing the electrical system but also makes it easier to manage and troubleshoot specific areas of the property.

The main panel and sub panel also differ in their capacity. The main panel is designed to handle the entire load of the building, while the sub panel is meant to handle only a portion of that load. This difference in capacity means that the main panel will have a higher amperage rating than the sub panel.

Electrical Sub Panel Benefits

Electrical sub panels provide several advantages, making them a valuable addition to any electrical system. Here are some of the key benefits:


If your main panel is full, a sub panel can expand your electrical capacity without the need for a complete overhaul. It provides additional slots for circuit breakers, accommodating more circuits.

This is especially useful in older homes where the main panel may not have enough space for new circuits.


Having a sub panel closer to the area where electricity is needed can make controlling circuits much easier. Imagine not having to trek across the house or property to switch off a circuit breaker. This convenience is particularly valuable in large homes or buildings with multiple floors.


Sub panels can save both time and money during installation. Instead of running multiple circuit lines back to the main panel, a sub panel allows for shorter, more efficient runs. This reduces the complexity of the electrical system and can lower labor costs.

Additionally, sub panels can improve the overall efficiency of the electrical system by reducing the length of wire runs and minimizing voltage drop.


Sub panels help reduce the risk of hazards associated with having multiple wires in a single circuit.

They also provide better emergency access and meet safety regulations by allowing more organized and accessible circuit management. By distributing the electrical load more evenly, subpanels can prevent overheating and reduce the risk of electrical fires.

arc fault breaker/ electrical sub panelCommon Uses of Electrical Sub Panels

Sub panels are often used in specific areas that require significant electrical power. Examples include:

  • Garage: For tools, lighting, and sometimes electric vehicle chargers.
  • Outbuilding: Such as a barn or shed with lighting and equipment.
  • Workshop: Where power tools and machinery are used.
  • Room Addition: To accommodate new electrical demands.
  • Home Office: Especially important with the rise of remote work.
  • Home Theater: For high-end audio and visual equipment.

Each of these applications requires a dedicated electrical supply to ensure that the equipment and appliances in use receive adequate power. Sub panels provide a practical solution by allowing you to add circuits without overloading the main panel.

When to Install an Electrical Sub Panel

Indicators that you might need a sub panel include:

  • Overcrowded Main Panel: If your main panel doesn’t have enough slots for new circuits, a sub panel can provide the additional space needed.
  • Difficulty Finding Circuit Breakers: A sign of a disorganized system. A sub panel can help by organizing circuits for specific areas.
  • Heavy Reliance on Extension Cords: Indicates the need for more outlets. Sub panels can add circuits and outlets where they are needed most.
  • Consultation with a Licensed Electrician: Always a good step to ensure your electrical system meets your needs safely. An electrician can assess your current system and recommend the best solution for your needs.

When Not to Use an Electrical Sub Panel

There are times when a sub panel isn’t the right solution. Indicators that you might need a complete electrical panel upgrade instead include:

  • Frequent Tripping: A sign of overloaded circuits that may require a full upgrade.
  • Dimming Lights: When multiple appliances are in use, indicating that the electrical system is struggling to keep up with demand.
  • Warmth in the Main Circuit Breaker Panel: Indicates overheating and the potential for electrical fires.
  • Warm Outlets or Burning Odor: Serious signs of potential electrical fires that require immediate attention.
  • Outdated Electrical Panel: Might not support the power needs of modern appliances and should be upgraded to a more current standard.

This is Not a DIY Project

When considering the installation of an electrical sub panel, it might be tempting to save money and attempt a DIY project. However, this is one area where cutting corners can lead to significant risks and additional costs.

Risks of DIY Electrical Sub Panel Installation

Installing an electrical sub panel requires a deep understanding of electrical systems, local codes, and safety protocols. Without proper knowledge, DIY installation can result in:

  • Electrical Fires: Improper wiring and connections can cause short circuits and fires.
  • Electric Shock: Handling electrical components without proper training can lead to severe or fatal shocks.
  • Code Violations: DIY installations often fail to meet local building codes, leading to fines and mandatory corrections.
  • Insurance Issues: Faulty electrical work can void your homeowner’s insurance, leaving you unprotected in case of accidents.

Potential Hazards of Non-Professional Installation

Non-professional installation of electrical sub panels can lead to numerous hazards:

  • Overloaded Circuits: Miscalculating the electrical load can cause circuits to overload and trip frequently.
  • Improper Grounding: Incorrect grounding can lead to electric shocks and equipment damage.
  • Inadequate Wiring: Using the wrong wire sizes or types can result in overheating and fire risks.
  • Future Repair Costs: Mistakes made during installation can be costly to fix and may require a complete redo by a professional.

Recommendation to Seek Professional Help

Given the risks and complexities involved, it’s strongly recommended to seek professional help for sub panel installation. Certified electricians have the expertise and tools to handle the job safely and efficiently, ensuring your electrical system is both reliable and compliant with all regulations.

Safe an Effective Electrical Panel Repair & Replacement

Lightning Strike EvaulationWhen it comes to ensuring the electrical safety and efficiency of your home or business, choosing the right professionals for the job is important. Right Touch Electrical stands out with a reputation built on quality and expertise.

We understand that your electrical panel is a critical component of your overall electrical system. Whether you’re dealing with an outdated panel, frequent circuit breaker trips, or planning an expansion, we offer solutions to meet your needs.

Our commitment to delivering “quality with a master’s touch” ensures that you receive the best possible service.

Final Thoughts

Understanding the role of an electrical sub panel can make managing your electrical system easier and safer. Whether you’re expanding your home, adding a new workspace, or simply needing more capacity, a sub panel can be a practical solution.


What is the main difference between a main panel and a sub panel?

The main panel is the primary point of connection for electricity entering your home, while a subpanel distributes power to specific areas and is fed by the main panel.

Can I install a sub panel myself?

While it is possible, it’s recommended to hire a licensed electrician to ensure safety and compliance with local codes.

Do sub panels provide additional protection against power surges?

Yes, sub panels contain circuit breakers and fuses that offer additional protection against power surges.

What are some common signs that I need a sub panel?

Overcrowded main panel, difficulty finding circuit breakers, and heavy reliance on extension cords are common indicators.

Why might I need an electrical service upgrade instead of a sub panel?

Frequent circuit breaker resets, dimming lights, and warm outlets indicate that your system may be overloaded and in need of an upgrade rather than just a sub-panel.

How does a sub panel improve the efficiency of an electrical system?

By reducing the length of wire runs and minimizing voltage drop, sub panels can improve the overall efficiency of the electrical system.