fair - what is a DC bonding system?
Metal thru-hull fittings that are wired (bonded) together along with the negative side of the DC system. Galvanic current can occur between two boats near each other in salt water when they both have underwater thru-hull fittings connected to their negative DC system which is also connected to the shore power ground connection. This is basically a battery, two boats tied together via the shore power ground and their underwater thru-hulls. Galvanic voltage levels are generally under 1 volt and the isolator will prevent these currents while still providing protection from AC shorts on board. Sounds like you probably don't need one.