Grounding of instrumentation amplifier is related to common mode and differentional mode currents. This is related to electromagnetic interference and electromagnetic compatibility. It depends on circuits and related instruments on its input and output. In some cases, isolation devices are required. The shielding becomes necessary, if there are higher frequencies (e.g. above 10MHz) or higher voltages and currents that could superimpose their waveforms on the instrument signal via the stronger electromagnetic emissions (EMI). Often, shielding screens or meshes, and metallic enclosures are applied. Also twisted shielded cables or coaxial cables are applied. Frequently, the manufacturers' tech support have numerous handouts in their catalogs and manuals, how to have their products grounded and shielded adequately.
