For a system designer working with high voltage and high-voltage isolation, one of the most important tasks is to choose the right digital isolator for the system. Electromagnetic compatibility (EMC) is a key consideration on which this choice hinges. An in-depth understanding of how the different EMC tests are performed help in making this decision correctly. It also helps in differentiating the isolator’s true performance in the actual system versus the claimed performances on a far from practical test setup. This paper discusses EMC standards and test setups for the relevant EMC parameters.