What Size Sub-Panel Should I Install for My Garage?

How to Install a Sub Panel for a Garage: Where to Begin when Installing a Sub Panel for a Garage, Planning for a Sub Panel, Identify the Sub Panel Circuits, Sizing a Garage Sub Panel, 120 Volt and 240 Volt Circuits, Planning for Future Circuits. © By: Dave Rongey

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Installing a Sub Panel for a Garage
Electrical Question: I currently have power ran out to my garage, however it only runs 2 lights and the wiring is old.

• I would like to upgrade and put a breaker box in the garage so I can put in more lights, outlets and run a pool pump, etc.
• I am not sure what size wire I need to run to the breaker box or what size box I need.
• I  need everything to be GFI protected.
• I’m competent I can do the outside wiring and will hire a professional electrician to tie into my house service.

Any advice would be greatly appreciated.
Thanks
Received from Danny a Homeowner in West Frankfort, IL.

Dave’s Reply:
Thanks for your electrical wiring question.

How to Install a Sub Panel for a Garage

Application: Adding a Sub Panel to a Garage.
Skill Level: Intermediate to Advanced. This electrical wiring project is best performed by a Licensed Electrical Contractor or Certified Electrician and is Not Recommended for Homeowners.
Tools Required: Electricians tools, pouch of hand tools and the various power tools necessary for installing the sub-panel.
Estimated Time: Depends on the type and size of the panel and available access to the project area.
Precaution: Any existing electrical wiring within the immediate area that may interfere with the installation of the sub panel should be identified and turned OFF and Tagged if necessary. Working in an electric panel is dangerous due to arc flash hazards and the possibility of electric shock.
Notice: Installing additional garage electrical wiring and a garage sub-panel should be done according to local and national electrical codes with a permit and be inspected.

Where to Begin when Installing a Sub Panel for a Garage

• Planning for a Sub Panel
  • As with any electrical project, planning is everything, and it is best to start with the end in mind. By this I mean to make a list of all the electrical devices you will be powering from the garage sub-panel.
• Identify the Sub Panel Circuits
  • Plan for any possibility for extra loads as well. This will be essential to select the right amperage size and how many circuit breaker spaces you will need. GFCI breakers take up a full space or two depending on what your powering.
• Sizing a Garage Sub Panel
  • When I install a sub-panel in a garage I always start with 60 amps, especially if the owner will be using tools for a workshop setup.
• 120 Volt and 240 Volt Circuits
  • Welders, air compressors, a vacuum system, lathe and more – it all adds up. Understanding that most equipment will not be running at the same time. Just don’t size the panel too small.
• Planning for Future Circuits
  • If you’re on a budget and you can’t size large now, and if you will be using a conduit to provide the feeders, make sure it is large enough to up-size the wire or pull in parallel feeders if needed in the future.
• Permits and Inspections
  • Make sure to get a permit and the required inspections.
• Help from a Qualified Contractor
  • For best results and to make sure the job is done right consider hiring a licensed electrical contractor.

More about Home Electrical Circuits and Sub Panels

Basic House Wiring Circuits

House Wiring Circuits and Circuit Breakers

This article looks at common 120 volt and 240 volt house wiring circuits and the circuit breakers that are installed identifying the types and amperage sizes used in most homes.
Electrical Panel Circuit Listing

Home Electrical Circuits

Electric Circuit Listing

The size of the home electrical service panel is designed by calculating the square footage of the home and factoring in the code requirements for the electrical circuits that are required.

How to Install Workshop Electrical Wiring

Work Shop Electrical Wiring

Fully Explained Photos and Wiring Diagrams for Workshop Electrical Wiring with Code Requirements for most new or remodel projects.

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