Full galvanic isolation is the ultimate "surge" protection when it comes to
minor ground potential differences. In fact, standard heavy-duty lightning
prottection units can actually compromise your isolation and create grounding
problems of their own.
But with large disturbances - such as
lightning discharges - the isolation barrier of 2500 volts may be to low.
Therefore, RobustDC has designed a special lightning protection unit (LPU)
fully optimized for use with our fully isolated RS-422 and RS-485 devices.
to view a PDF file.