Do you know how Batman has the Batcave, which operates as his headquarters and the control center for all his superhero duties? While you may not have a super cool Batcave replica at your business, you do have an electrical system. Electrical panels act as the control center for your home or business, so it’s imperative that they are the right size for the job.

There are two types of electrical panels to consider:

  • Main circuit breakers, and;
  • Sub panels

Let’s take a closer look at different commercial electrical panel sizes so that you can have the correct amount of power in your Batcave— er, we mean, your business!

What Does a Main Electrical Panel Do?

As we mentioned, your main electrical panel is essentially the control center for your property. Power is fed directly from your utility company into your electrical system. The electrical panel then sources out that electricity to all the devices and appliances that require it.

You can identify the main electrical panel as a metal box with a door that’s built into your wall. It includes:

  • A switch for connecting and disconnecting power
  • Subpanel controls and outlets (More on subpanels later!)
  • Durable breakers and wiring
  • Voltage regulators

Not only do main panels take in the initial connection of electricity for your home or business, but they’re also the first line of defense against electrical surges.

The Two Main Types of Circuit Breakers


There are two primary types of commercial electrical panels: single-phase and three-phase. These two types have different sizes and capabilities for various electrical needs.

1) Single-Phase Systems

Single-phase electrical panels are the most common type of electrical system. This system is ideal for smaller commercial businesses and homes that don’t have a significant amount of electrical needs. Most homes utilize single-phase power, but it’s not usually enough power for larger commercial businesses.

2) Three-Phase Systems

Three-phase power is more robust, efficient, and powerful. There really isn’t a need for the average-size house or small storefront to use a three-phase system, but it is used in larger commercial buildings like:

  • Factories
  • Hospitals
  • Office buildings
  • Sports arenas
  • Shopping malls

The three-phase system allows more amperage to flow through the circuit breaker without overheating the wires— which is exactly why it’s ideal for larger commercial spaces.

Where Size Comes In: Sub Panels

At a certain point, your main electrical panel may just not cut it anymore.

You may need to upgrade the size of your electrical panel because you’re using more electrical power than your breaker can support. While you can initially upgrade to a more modern and larger three-phase panel, there comes a point where main electric panels simply don’t get any bigger.

If you need to supply more power than your main breaker can handle, you’ll likely need to install sub panels to accommodate.

Just like main panels, electrical sub-panels come in different sizes. Sub-panels have the same wires and bus bars as main panels, but they don’t include a main shut-off breaker. That’s still powered through your main panel.

Sub-panels are typically installed to service a specific area of your commercial business— such as a new room addition or an area with more large appliances. When your electrician chooses a sub-panel size, they actually need to pay attention to the electrical load on certain models.

Areas with minimal electrical needs can be successfully served by a small panel that ranges from 30 to 60 Amps. However, entire room expansions or heavy-duty commercial equipment will need a larger sub-panel that ranges from 60 to 100 Amps.

In order for electricians to identify the proper size sub-panel for your needs, they take the following three points into consideration:

1) Follow the National Electric Code

Electricians must follow all local electrical codes when installing new electrical equipment or repairing existing systems. Many times, local codes fall under the National Electrical Code (NEC). If so, they follow “long form” load calculations which add up the usage (wattage) of all the devices and appliances powered by the sub-panel. This total sum is divided by 240, and the result is the minimum necessary amperage capacity.

2) Find the Coverage Area

The size of the area the sub-panel is intended to serve is instrumental in finding the right side panel. One way to do so is. to add up the total area of the space in which the sub-panel will supply power.

Find the square footage of any and all areas needing power. Find the square footage by multiplying the length of the room by the width. Then, multiply that total number by 3 watts.

3) Calculate the Wattage

Each appliance requires a different wattage, so your electrician will need to collaborate with you to determine how much wattage you need to support. If you’re adding a kitchen to an office building, you’ll need to account for portable and fixed appliances like:

  • Dishwasher
  • Microwave
  • Toaster
  • Electric stove
  • Garbage disposal
  • Coffee maker
  • Air fryer

The total wattage can be found by multiplying the sum by 1 if there are less than 4 fixed appliances or by 0.75 if there are 4 or more appliances.

The combination of these three considerations will help your electrician suggest the correct sized sub-panel to install.

Partner With an Experienced Commercial Electrician

common electrical panel sizes finding best electricians

Feeling ready to upgrade your electrical system? You definitely don’t want to attempt this project by yourself. Instead, work with a qualified electrician that has experience with commercial properties.

Here at Electric City, we’ve been serving home and business owners across Minnesota since 2012! We’d be happy to help you find the right size electrical panel for your business. Simply get in touch for a free consultation!