For integrating the mounting systems, e.g. of PV installations into the functional equipotential bonding / functional earthing (possibly black conductor) and lightning equipotential bonding according to IEC/EN 62305-3. The StSt contact plate (intermediate element) allows different conductor materials (Cu, Al, St/tZn and StSt) to be connected to the normal mounting systems, e.g. to aluminium, without the risk of contact corrosion.