Varitector PU (VPU) Surge Suppressors Weidmuller Varitector PU (VPU) Surge Suppressors are proven surge protection devices that are available in variants with integrated fuses. This eliminates the need for an additional fuse before the SPD. The combined type II+III surge protection devices have one backup fuse per protective path and are used universally in power distribution systems. The application-oriented pluggable product configurations allow flexible use in different network types.