These protective devices are used to safeguard electrical circuits against overloads and short circuits. In summary, fuses are protection devices used to protect electrical circuits from overloads and short circuits. A fuse contains a metal filament that supports a certain current value. When a current exceeding the limit value—called the breaking current—passes through the fuse, the current is interrupted.

How do they work?

Fuses are simple devices. They consist of metal filaments, often made of lead or tin, that act as the fusing elements. The filament of a fuse can withstand a certain current limit. In other words, as long as the current passing through it remains below the limit value, the filament allows its passage. The metal filament melts and interrupts conduction, preventing the overload from damaging the electrical installation.

They should also be used in photovoltaic systems when the intention is to protect strings and photovoltaic arrays against reverse currents. Typically, reverse currents are a possibility when a circuit has three or more photovoltaic arrays in parallel. This is because, in the event of a problem in one of the strings, the defective string can be fed with the current from the other two strings, which can damage the modules and even cause a fire in the photovoltaic plant.

In the photovoltaic industry, the fuses used are generally gPV fuses, which are specially designed to protect solar systems. Additionally, the size of the fuses to be acquired varies according to the system’s voltage level and the maximum current supported by each module, a value specified in its data sheet. Since the standard mandates their use only in systems with three or more parallel strings, their use is not common in systems with fewer parallel strings.

THS offers a complete line of fuses for various operations that ensure greater safety in maintaining photovoltaic systems or any electrical installation. Check out these and other components on our website.