Uncertainties in EMC compliance testing

After an EMC compliance test has been successfully applied to an equipment and the test engineer declares that this equipment does or does not comply with the specified requirements, a relevant question seems to be ´How certain is this test engineer that indeed the equipment does or does not comply with the requirements?´ In other words: ´What uncertainties play a part in EMC compliance testing and what is-with a certain level of confidence-the magnitude of the associated compliance uncertainty?´ Important contributors to this uncertainty are given together with illustrative examples. These contributors include aspects of the way the (standardized) EMC test is formulated, measuring equipment tolerances and calibration, EMC test-engineer skill, and traceability of the (standardized) EMC compliance test. Some consequences for today´s EMC standards, and the writers of EMC standards are discussed. Incorporating EMC compliance uncertainty in a compliance criterion is only possible after improving the traceability of the EMC standards, the formulation of the specifications, the calibration of measurement equipment and description of test set-ups. Also a sound estimate of the maximum allowable compliance uncertainty is needed