NEN1010 prescribes that all metal parts in a PV mounting system must be connected to each other. This means that cable trays and the mounting system must be connected to each other. A wire diameter of 4mm2 is sufficient for equalization.
A connection wire between the mounting system and lightning conductor is mandatory when the distance between the lightning conductor and the mounting system is anywhere <0.5m. In that case, the connecting wire concerned must have 16mm2 (equal to the lightning conductor wire).