The dual-numbered European designation of the residential generic immunity standard exists because CENELEC adopted the international text without technical change, republishing it under both the European and the international numbers with a foreword confirming the unmodified adoption and an annex relating the document to the directive it serves. For the engineer preparing a test plan the two designations are interchangeable: the dual-numbered document, the plain European document and the international standard contain the same port-by-port tests at the same levels, and the difference appears only in the technical file and in the declaration of conformity, where the edition currently cited is the one that should be named. It is worth noting at the same time that the generic standards are displaced by any applicable product or product family standard, so a manufacturer must first establish that no such standard covers the product before choosing this route.