Solar System Circuit Breaker Types and Applications

Home Solar System Circuit Breaker Types and Applications

Based on their capacity, solar PV panels may have one or more installations. A DC circuit breaker is required to protect the circuits connected to a PV combiner box. The solar panels can be used with a single-directed current output thanks to the way in which all the power is combined through them. 

Many DC circuit breakers would need to be installed if there were many DC load panels. Solar-panel owners are able to use direct current in their homes for various purposes. DC circuit breakers are necessary for these circumstances for shielding. Many different solutions need to be developed. Let us know about circuit breaker types and applications further.

What Is a Solar System Circuit Breaker?

Molded Case Circuit Breaker
Source: Beny

A switching device known as a circuit breaker protects users by trip-tripping and cutting off power to a load in the event of an error. Circuit breakers are primarily used for switching various types of loads.

A double pole DC breaker or isolator with ratings to break 1.25 times the solar PV array’s Short Circuit Current (Isc) rating AND 1.2 times the Open Circuit Voltage (Voc) of the array is required for transformer isolating inverters.

Types of Solar System Circuit Breaker

Standard, GFCI, and AFCI circuit breakers are the three types of solar system circuit breakers available. Each manages various amp capacities and works in various locations of the place.

Sizes in Solar System Circuit Breaker

A 30-amp fuse is necessary for each panel when the panels are connected in parallel. 20 amp fuses are necessary if the panels are less powerful than 50 watts and only use 12 gauge wires. Fuse and inverse time circuit breakers’ standard ampere size varies between 15 and 6000 amp.

Why Do We Need Circuit Breakers for the Solar System?

Circuit breakers are an important component of the solar system. Between Direct Current and Alternating Current, it serves as a barrier. A barrier between the panels and the alternating current is necessary for installation and routine maintenance. Electric protection requires the use of circuit breakers.

Because they can continue to operate even when the alternating current unit has completely failed, circuit breakers are essential. When used, they may require less maintenance, be more dependable, and have a lower failure rate.

In order to better understand why circuit breakers are so important for solar systems, this blog will attempt to do so. Circuit breakers are necessary to guarantee that the photovoltaic panel’s quality endures for a longer time.


Circuit Breaker Applications
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Solar-panel owners are able to use direct current in their homes for various purposes. DC circuit breakers are necessary for these circumstances for shielding. Many different solutions need to be developed. Additionally, they need to set up separate fuse boxes with lots of circuit breakers for both alternating and direct current. DC circuit breakers have the ability to control the direction of current flow.

As a result, changing the direction accidentally or intentionally would raise safety issues and harm the solar cells. In the case of LED lamps, a light-emitting diode can be used to power them. However, this function can only be performed in the presence of a direct current.

Considering Factors While Choosing a Solar System Circuit Breaker

Choosing a circuit breaker
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Circuit breaker selection in solar PV systems is something that is easily forgotten, so care should be taken to choose the best option. Equipment will frequently trip the circuit breaker, which can lead to overheating damage and even system fire.

When choosing circuit breakers for solar panels, certain factors must be taken into account. The list of crucial elements is as follows:

  • The Number of Strings in the Isolator

If there are two poles, only one string should be present. There should be two strings when there are two poles. You can choose from several string panels for isolators that transport external direct current. A single maximum power point tracker that can also function as a converter would be compatible with a common string inverter for in-built DC isolators.

  • The Impact of Installations on the Environment

Normal operating conditions for DC isolators range from -40 degrees Celsius to 60 degrees Celsius. Because temperatures are crucial to understanding the protection and fireproof systems, they must be monitored during the installation process. UL 94V-0 to UL 94V-2 should be able to be controlled by the enclosure box.

  • Size of the System’s Voltage

Isolators carrying operational voltage should have a higher or equivalent voltage to that required by the system. The most typical specifications are 1500V, UL508i 600V, and IEC60947-3 1000V, although single-phase inverters connected to system voltage can typically operate at 600V. The system voltage for three-phase string inverters can go as high as 1000V and 1500V. The same would be true for centralized inverters.

How to Calculate Circuit Breakers in Solar PV System

Calculate circuit breakers
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  • The maximum continuous output current of the inverter is multiplied by the factor.

For example, 30A x 1.25 = 37.5A

  • Round the rated size determined in step 1 to the nearest common size of the circuit breaker. 

Hence, the formula is simply the inverter’s maximum output current multiplied by a safety factor of 125%, rounded to the nearest breaker size.


Circuit breakers are a crucial part of solar energy systems. Photovoltaic panels may become more vulnerable to damage and system failure without their protection. Circuit breakers and alternating current breakers each have specific functions within the system. They are both crucial for proper operation as a result. 

Circuit breakers can serve as the prominent shield that is required by numerous systems, such as photovoltaic panels, if the proper wiring guidelines, safety precautions, maintenance, and procedure are followed.

Visit the Beny website to learn more about the best photovoltaic system protection options and how circuit breakers work. You can get all the necessities from there, along with the information you require.

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