What is an Electrical Subpanel

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The heart of every home's electrical system is the main circuit breaker box, also known as the main service panel. The main service panel is usually located in a utility room, garage, or basement. The panel contains the breakers or fuses that protect your home's electrical circuits from overloads.

Wiring a home can be a daunting task, especially if you're not sure how it all works. You might be tempted to skip some of the steps or try to do it yourself in order to save money, but this can be dangerous and could lead to an electrical fire, and that's where the electrical subpanel comes to the rescue.

The basic structure of an electrical subpanel is the same as a service panel, with the main wire leading into the bus bars and circuit breakers.

What is an Electrical Subpanel?

An electrical subpanel, also known as a service sub panel or circuit breaker sub panel, is a smaller service panel that distributes power to a specific area in your home. It is typically used to power an additional circuit in your home, such as for a new appliance or to provide more amperage to an existing circuit. 

What is an Electrical Subpanel?
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A subpanel can be a great addition to your home if you find yourself constantly tripping circuit breakers or running out of outlets. It acts as a waypoint between the main service panel and branch circuits further down the electrical line. An electrical subpanel can be thought of as a mini service panel.

Benefits of Installing an Electrical Subpanel

Electrical subpanels are added to a home for three main reasons, including space, convenience, and efficiency. If you're trying to add new electrical circuits and your main panel is full, you should have a subpanel installed by a licensed electrician. Here are other reasons for installing an electrical subpanel:

Benefits of Installing an Electrical Subpanel
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Inaccessible Service Panel

If your service panel is in a tight or difficult-to-reach spot, an electrical subpanel can provide easier access for adding new circuits or making repairs.

Metering Not Separate from the Main Service Panel

If your utilities are metered at your main service panel, an electrical subpanel can provide a place to put new circuits without running meters past them. This is more efficient and can save you money on your utility bill.

Main Service Panel Breaker Capable of Shutting Off

Even though the electrical subpanel has its circuit breakers, all power running to that subpanel is still fed from one circuit located in the main service panel. The feeder circuit is protected by a double pole circuit, and this breaker is capable of shutting off.

Electrical Subpanels Create More Space

An electrical subpanel gives you the ability to add more circuits without having to worry about overloads. This is because each circuit in the subpanel is on its breaker. You can also use an electrical subpanel to create more space in your main service panel.

Electrical Subpanels Ease Wire Routing

Wiring can be a bit of a challenge, especially when it is routed through tight spaces. An electrical subpanel can ease the routing process by providing more space to work with. This is especially helpful when trying to run wiring behind walls or in other tight spots.

Installing an electrical subpanel near the remodel area means that only one cable needs to be run from the main service panel to the subpanel. This can save you time and money on your remodel project.

Electrical Subpanels Clarify the Circuitry

When you are remodeling, it is often necessary to add or change the wiring in your home. With an electrical subpanel, you can easily identify and isolate the circuits associated with the remodel area. This can help prevent any confusion or problems when it comes time to test the newly installed wiring.

By installing a circuit breaker subpanel, you clarify which circuit breakers and branch circuits apply to which parts of your house. It's easy to segregate the duties of all the branch circuits by keeping them in their little world within the subpanel.

An electrical subpanel is simply a mini circuit breaker panel containing its branch circuits. The main breaker in the main panel controls power to the subpanel. From there, each circuit in the subpanel is protected by its circuit breaker. Calculating electrical load capacity for a home can also be done through electrical sub panels.

How to Install an Electrical Subpanel

What You'll Need

  • Screwdriver
  • Hammer
  • Voltage tester
  • Flashlights
  • Strippers
  • Longnose pliers
  • Lineman's pliers
  • Subpanel
  • Mounting screws
  • Breakers for the new circuits
  • Approved feeder breaker
  • Approved feeder cable
  • Staples or cable clamps


Start by Mounting the Subpanel

Before mounting the subpanel, make sure you know how to wire an outlet as this is required in any electrical project. Mount the subpanel about a foot away from the main service panel. Determine how far the wires will have to travel in the subpanel and pull wires or add cable and strip sheathing accordingly. Then, remove a knockout slug, slide the wires through and clamp the cable.

Plan Route of Wires

Route the wires from the service panel to the subpanel. At the main service panel, plan the routes for four wires. There's the ground wire, a neutral wire, and two hot wires, black and red. Route the neutral and ground wires carefully and connect them to their bus bar.

Strip Wires

Strip insulation from the wires using a wire stripper. Loosen the screws on the clamp and insert the stripped wire into the clamp. Tighten the screw to hold the wire in place. Route, cut, and strip the red and black wires. Connect them to the feeder breaker, then snap the breaker into place.

Strip Wires
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Connect Wires

 Connect the wires to the screws on the subpanel. The black wire goes to the brass screw, also known as a hot screw. The red wire goes to the silver screw, the neutral screw. Tighten the screws firmly. Connecting wires improperly can create a dangerous electrical hazard. Connect the black and red wires to the hot bus bars, the neutral wire to the main neutral terminal, and the ground wire to the ground bus bar.

Connect Wires
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Finish Connecting Wires

Close the door to the electrical subpanel. Run cable for new circuits and clamp the cable. Route wires around the perimeter, connect the ground wire to the ground bus bar, and the hot wire to a circuit breaker for each circuit.

FAQs on What is an Electrical Subpanel

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

The main panel is an installed box where the power from the utility company enters the premises. A subpanel is an installed feature that acts as a middle ground for the main panel and other types of circuits that are connected to your property.

Can the main panel be used as a subpanel?

Yes, you can use the main panel as a subpanel because it is the source of all the power for your property.

Can I install a subpanel without permission from the utility company?

No, you cannot install a subpanel without permission from the utility company because it would tamper with their equipment.

Final Thought on What is an Electrical Subpanel

Installing an electrical subpanel in your home is very important as it can help you easily manage the circuits in your property. It is also a very useful tool in case of an emergency as it can help provide power to certain areas of your home. Remember to get permission from the utility company before installing a subpanel in your home.

Read our article on what is a service panel as well!



Ben James

Ben James

Ben is an experienced content writer with a passion for kitchen remodeling. He loves writing about latest kitchen designs & trends so that he can educate our readers make the best decisions possible when it comes to kitchens.

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