Lightning impulse current and surge arresters type T1+T2 intended for photovoltaic systems (PV) at U or Y connection. The advantage of the Y connection versus the U connection is the resistance to the earth connection of the working conductors and zero residual (leakage) current through the PE conductor. Particular varistor sectors, connected between the terminals L+, L- and PE are equipped with internal disconnectors, which are activated when the varistors fail (overheat). These devices are necessary to be used with the back-up fuse with external disconnector, which is intended for PV applications. They are installed on the DC side in PV applications with external LPS, where a sufficient distance "s" is not observed. Suitable for level LPL I or II. Ensure the equipotential bonding of plus and minus busbars of PV systems and the elimination of transient overvoltage resulting from the atmospheric discharges (including direct lightning strike to the PV system) or switching processes. S indication specifies a version with remote monitoring.