Noark DC surge arresters are designed to protect photovoltaic applications. They are designed and manufactured in accordance with the standards of EN 61643-31, tested according to the PV class T1+T2 test. An optical status indicator of the varistor insert informs about the wear of the element. Built-in auxiliary contact allows electrical signaling of the status of the insert. Safe replacement of a worn varistor insert is possible without disconnecting the device.