IEC 61000 are "basic" standards which contains the measurement techniques. IEC 61326 is a Product Family standard which contains conditions, limits and performance criteria for equipment for measurement, control and lab use.
Standards are applicable in this order
- Product Standard, if applicable, otherwise
- Product Family Standard, if applicable, otherwise
- Generic Standard
61326 is mentioned in this hierarchy here:
The structure of EMC standards
EMC requirements are specified in a vast number of standard documents
issued by various committees and organizations. The documents are
organized as follows:
Basic standards: Describe the phenomenon, characterize the test
equipment and give guidance how tests shall be performed and
documented. Basic standards like IEC 61000-4-x form the lowest level
in standard's hierarchy.
Generic standards: Specify test levels for a certain range of
application, referring to the Basic Standards for general information.
Generic standards give minimum requirements, e.g. for CE Mark (EN
61000-6-1). Generic Standards stand above the Basic standards.
Product Family standards: Are used where exist for a certain category
of products. They specify test levels and performance criteria. EN
61326, for instance, forms such a Product Family standard dealing with
the EMC requirements of equipment for measurement, control laboratory
Product standards: Are the most preferred standards as they give
strict requirements for a certain product. EN 61800-3 for instance is
a Product Standard for adjustable speed electrical power drive
systems. Apart from the requirements for EMC this standard also
defines special test procedures. Product Standards form the highest
level in standard's hierarchy.
Source: EM Test
but all can refer to the basic standards for the measurement techniques.