This Guide presents a practical approach to the application of uncertainty of measurement toconformity assessment activities in the electrotechnical sector. It is specifically conceived foruse in IECEE Schemes as well as by testing laboratories engaged in testing electricalproducts to national safety standards. It describes the application of uncertainty ofmeasurement principles and provides guidance on making uncertainty of measurementcalculations. It also gives some examples relating to uncertainty of measurement calculationsfor product conformity assessment testing.