Units with additional I/O terminal block (option +L504): Ground the pair-cable shields and
all grounding wires to the grounding clamp below the terminal block as shown below.
At the other end of the cable, leave the shields unconnected or ground them indirectly via
a high-frequency capacitor with a few nanofarads, eg, 3.3 nF / 630 V. The shield can also
Electrical installation 127