The EXG Ground TP is required when using touch proof (TP) NeXus sensors such as the EXG Sensor TP and the SCP Sensor in order to guarantee signal quality. Measuring electrophysiological signals always requires a ground.
EXG Ground TP connects to the ground input (Gnd.) of the NeXus-4 NeXus-10 or NeXus-32.