This industry guide is the result of activities performed by METAS, INRIM, University of Campania and VSL within the project “Standardisation of measurements for DC electricity grids” (20NRM03 DC grids, see https://DC-grids.nl). In this industry guide, a set of significant test waveforms for DC electricity meter testing is presented. The selection has been driven by two main criteria: on one side, the consistency (when applicable) with similar tests performed on AC electricity meters; on the other side, the analysis of real-world waveforms as acquired in different DC microgrid installations. Based on these considerations, this industry guide represents a first attempt to identify the most significant power quality issues that may affect DC electricity meters, and discusses their potential consequences in terms of measurement error and uncertainty.