When installing a solar panel system, you have to be familiar with the electric breakers and how it works with a solar PV system to avoid future electric problems. The electric breaker is one of the main components of a solar power system that provides safety mechanisms. If ever the electrical wiring of your system has too much current flowing through it, these breakers can easily cut the power until your solar installer can fix the system’s problem.
For today’s article, we will discuss electric breakers and their function in solar photovoltaic systems.
What is an Electric Breaker?
An electric or circuit breaker is an electrical switch designed to protect electrical circuits from damage caused by overloading of current or a short circuit. The basic function of an electric breaker is to prevent the current flow once protective relays detect a fault in the system.
Although it is frequently interchanged with a fuse, which is the simplest Over Current Protection device (OCPD) in electrical circuits, a circuit breaker, is a much-evolved type of device that interrupts the current flow. The main difference between the two is electric breaker is resettable and the fuse is not. The fuse sacrifices itself while protecting the system to overheat, while the circuit breaker can withstand hundreds and thousands of operations. Another difference is that electric breakers are used with relatively higher currents.
Components of Circuit Breaker
A circuit breaker system is composed of three parts. These three components are the sensing system, relay, and the combination of contacts and the contact actuator. A sensing system is responsible for detecting an overload situation, while a relay is responsible for transferring the information to the switching arrangement, and the combination of contacts and the contact actuator. This electric arrangement is usually observed in power transmission and distribution networks dealing with very high currents, voltages, and powers.
Circuit Breakers Calculation in Solar Panel Systems
When connecting circuit breakers to the PV system, you have to follow the recommended calculations to avoid future problems and damage to the entire system. The recommendations for using overcurrent protection devices including circuit breakers in solar modules against overloading conditions are given in IEC 60269-6 (volume 6 of IEC 60269-6) and also UL 248-19.
For circuit breakers, IEC recommends a 20% and 25% margin in voltage and overload current. Most of the time, the ratings are specified by the solar manufacturers at given ambient conditions. If the temperatures exceed this given value, derating must be applied according to the manufacturer’s specifications.
When it comes to breaker sizes for solar panels, NEC requires the breakers to be sized at 125% of the inverter’s rated output. So a 7680W inverter that outputs 240V, outputs 32A (7680W ÷ 240V = 32A). That requires a 40A breaker (32A x 125% = 40A).
If you owned a solar panel system at home, you have to understand how circuit breakers work to prevent catching fires at home. These devices are one of the major components of the PV solar system as they protect the system wiring from getting too hot and accidentally catch fire if short circuits occurred. Thus, understanding the breaker itself and its proper calculations in the PV system should be done.