Function: It protects electrical systems and equipment from sudden voltage spikes or surges. Application: Commonly used in photovoltaic (PV) solar systems and other low-voltage electrical components. Key Features: Available in various configurations, such as AC 4P (4-pole) models with specific voltage and current ratings (e.g., \(U_{c}\): \(\sim 420\text{V}\), \(I_{max}\): \(40\text{kA}\)).