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eBook Item #17

Circuit Breaker

(Between Bus Bar & Solar Charge Controller)

Purpose & Description:

  • Protects wire between bus bar and solar charge controller
  • Voltage range: 12V-48V
  • Manual reset button for easy disconnect

Circuit Breaker Size

  • Breaker size depends on wire size
  • 40A breaker recommended for 10 AWG wire
  • Use solar calculator to determine your size

What Size Breaker You Need

The size of this circuit breaker depends on the wire size you will use to connect the bus bar to the solar charge controller. 

Visit our solar calculator post to help you determine the size you need, or locate the breaker you need based on your solar array size below.

  • 190W (or less): 12 AWG wire & 30A breaker
  • 190W – 285W: 10 AWG wire & 40A breaker
  • 285W – 380W: 8 AWG wire & 60A breaker
  • 380W – 520W: 6 AWG wire & 70A breaker

* Breakers are sized conservatively and according to NEC guidelines to maximize safety

Frequently Bought Together

When using this 40A circuit breaker, below are the four most popular parts and tools you’ll need.

  • Solar Wire (red + black) – Use this wire to connect the circuit breaker to the solar charge controller and the bus bar. Learn more about this solar wire.
  • 1/4″ Ring Connectors – These ring connectors crimp onto the solar wire and attach to the breaker. Make sure you get the right size ring connector for your wire.
  • Irwin Vise Grip – Use this tool to cut, strip, and crimp the solar wires.

Where To Install The Circuit Breaker

The circuit breaker is commonly installed between the positive bus bar and the solar charge controller. Refer to the image below to visualize where this breaker is placed.

Solar Wiring Diagram (Part 3 - To Solar Charge Controller & Batteries)

Need More Wiring Information? Download our Electrical Wiring eBook.

Technical Details

Current Rating


Max Voltage


Product Dimensions

2.91 x 1.89 x 1.44 inches


1/4" Stainless Steel Studs

Housing is thermalplastic UL rated 94V0

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