Sproat Lake, Vancouver Island, BC

What is the difference between an AC breaker and a DC breaker?

What is the difference between an AC breaker and a DC breaker?

AC (Alternating Current) breakers and DC (Direct Current) breakers serve the same fundamental purpose, but what are the differences between them?

  • AC Breaker (Alternating Current Breaker)
  • DC Breaker (Direct Current Breaker)
  • Current Type:
  • Arc Extinction:
  • Voltage Rating:
  • Polarity:
  • Contact Material and Design:
  • Applications:

AC Breaker ( Alternating Current Breaker )

  • Think of AC like the electricity that powers most of the devices in your home, such as lights, TVs, and appliances.
  • AC electricity flows back and forth, like the back-and-forth motion of a swing.
  • An AC breaker is like a safety switch that can be turned off if there’s too much electricity flowing or if there’s a problem, like a short circuit. It’s like turning off the swing if it’s swinging too wildly.
  • AC breakers are designed to handle this back-and-forth flow of electricity, and they have a specific design to do that safely.

DC Breaker ( Direct Current Breaker )

  • DC is different from AC; it’s like the electricity in batteries, like the ones in your phone or a flashlight.
  • DC electricity flows in one direction, like a car moving in a straight line.
  • A DC breaker is like a safety switch for DC electricity. It’s used in situations where electricity flows in one direction, like in solar panels or some vehicles.
  • DC breakers are designed to handle this one-way flow of electricity and protect against issues in DC circuits.

Current Type:

  • AC Breakers: Designed to interrupt the flow of alternating current, which periodically changes direction. AC voltage and current alternate direction in a sinusoidal waveform.
  • DC Breakers: Designed to interrupt the flow of direct current, where the current flows in one direction continuously. DC voltage and current are constant in polarity.

Arc Extinction:

  • AC Breakers: AC circuit currents naturally pass through zero during each cycle of the waveform, which helps extinguish arcs when the contacts open. This natural zero-crossing point assists in breaking the circuit.
  • DC Breakers: DC circuits do not have zero-crossing points, so the arc formed when the contacts open can be more challenging to extinguish. Special arc-chute designs or arc-quenching technologies are often required in DC breakers to safely interrupt the circuit.

Voltage Rating:

  • AC Breakers: Typically designed for specific AC voltage ratings, such as 120V, 240V, 480V, etc. AC breakers are rated for the peak voltage of the AC waveform.
  • DC Breakers: Rated for specific DC voltage levels, such as 12V, 24V, 48V, etc. DC breakers are rated for the continuous voltage in the DC circuit.


  • AC Breakers: AC circuits alternate in polarity, so the breaker does not need to consider polarity.
  • DC Breakers: DC circuits have a fixed polarity, which means that DC breakers must be designed to handle the specific polarity of the circuit.

Contact Material and Design:

  • AC Breakers: Typically use materials and designs optimized for interrupting AC currents, as the voltage waveform assists in extinguishing arcs.
  • DC Breakers: Use materials and designs suitable for handling the potentially continuous arcs that can occur in DC circuits.


  • AC Breakers: Commonly used in residential and commercial electrical systems, where AC power is the standard.
  • DC Breakers: Commonly used in applications where DC power sources are prevalent, such as automotive systems, renewable energy systems (solar panels, wind turbines), battery systems, and industrial applications.

DC Breaker 15 Amp


It’s absolutely crucial to use the right type of breaker for a specific electrical system to ensure safety and reliable protection for the circuit. Attempting to use an AC breaker in a DC circuit or vice versa can lead to incorrect operation and potentially dangerous situations. To make sure everything works as it should, always follow the manufacturer’s instructions and guidelines when selecting and installing circuit breakers.

If you ever have questions or concerns about which type of breaker to use, or if you’re unsure about anything related to your electrical setup, please don’t hesitate to reach out to us at IOTG Solar. We’re here to provide clarity and guidance, explaining what needs to be done, and we’re always ready to assist you. Remember that both breakers and fuses are essential safety devices designed to protect you and your electrical systems. Your safety is our top priority, so feel free to contact us or give us a call anytime. We’re here not only to provide assistance but also to educate and ensure your electrical systems are as safe as possible.