The IEC has found it most practical and convenient to distinguish four product categories for EMC standardization purposes:
These are single finished products with a direct function and intended for final use, such as domestic appliances, medical equipment, tools and circuit-breakers. In principle, EMC product Standards must be developed for all such apparatus and, again, these Standards may serve for certification purposes.
In the EMC context, these are combinations of apparatus and/or components constituting a single functional unit intended to be installed and operated to perform a specific task. A good example is a computer system comprising a CPU, monitor, keyboard, mouse, printer, etc.
In this case, and in particular to ensure "internal" or intra-system compatibility, separate EMC Standards may be developed for each component or apparatus. To ensure "external" compatability with other systems in the same location, and for certification purposes, an overall EMC Standard for the whole system may be considered.