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Solar System Circuit Breakers: Types, Sizes, Applications, and How to Choose

Circuit breaker

Solar PV panels may have one or more installations depending on their capacity. DC circuit breakers are needed to protect the circuits connected to a PV combiner box. All the power is combined through the panels in a single-directed current output, making DC circuit breakers necessary for shielding when solar-panel owners use direct current in their homes for various purposes.

What is a Solar System Circuit Breaker?

A circuit breaker is a switching device that trips and cuts off power to a load in the event of an error, 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 managing various amp capacities and working in different 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, and 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 as they serve as a barrier between Direct Current and Alternating Current. Electric protection requires the use of circuit breakers as they can continue to operate even when the alternating current unit has completely failed. In order to better understand why circuit breakers are so important for solar systems, this article will explain the circuit breaker types and applications further.


Solar-panel owners are able to use direct current in their homes for various purposes, requiring DC circuit breakers for shielding. 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, making changing the direction accidentally or intentionally a safety issue and harmful to the solar cells. In the case of LED lamps, a light-emitting diode can be used to power them, but only in the presence of a direct current.

Considering Factors While Choosing a Solar System Circuit Breaker

Circuit breaker selection in solar PV systems is something that is easily forgotten, so care should be taken to choose the best option. When choosing circuit breakers for solar panels, certain factors must be taken into account, including the number of strings in the isolator, the impact of installations on the environment, and the size of the system’s voltage.

How to Calculate Circuit Breakers in Solar PV System

The maximum continuous output current of the inverter is multiplied by the factor, i.e., 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. Without their protection, photovoltaic panels may become more vulnerable to damage and system failure. Circuit breakers and alternating current breakers each have specific functions within the system, and both are crucial.