This guide applies to stationary Meter Test Units (MTUs) permanently installed in laboratories, used for testing and calibration of direct current electricity meters, in particular for their type test, acceptance test and verification test. It covers the requirements for automatic MTUs for indoor laboratory application and applies to newly manufactured MTUs to test electricity meters on direct current systems with a voltage up to 1500 V. For direct current electricity meters, IEC62052-11:2020 and IEC62053-41 ED1 are applicable.