Isolated and Non-isolated DC-DC converters
The isolated DC-DC converter is electrically separated between the input and the output terminals while the input and the output of a non-isolated converter share the common ground. Sometimes an isolated DC-DC converter is called isolated ground or galvanic isolated type. How to find out a DC-DC converter of isolated or non-isolated ? Simply use a digital multi-meter or any other ohm meter to measure the resistance between the ground terminals of the input and output of the converter. If the they shorted ( common) it is a non-isolated type , otherwise it is an isolated type.
Summary Isolated and non-isolated DC-DC converter
Non-isolated DC-DC converters are common and of lower cost , they are used in most negative ground application in vehicles for various DC powered appliances and equipment. However they have one big disadvantage in the electrical connection between the input and output which offers little or no protection to the load for any high electrical voltage , current and etc occurs on the input side. They also have less noise filtering blockage . Isolated DC-DC converters have high isolation (barrier) voltage from several hundreds to thousand volts depending on the type of standard . They can be used as negative grounded or positive ground or floating ground for various equipment from data com to telecom. They have strong noise and interference blocking capability thus provide the load with a cleaner DC source which is required for sensitive loads.