According to Rule 43(2), as applicable to all European patent applications in respect of which a communication under Rule 51(4) EPC 1973 (corresponding to Rule 71(3) EPC 2000) was not issued by 2 January 2002, the number of independent claims is limited to one independent claim in each category.
Exceptions from this rule can only be admitted in the specific circumstances defined in sub-paragraphs (a), (b) or (c) of this rule, provided the requirement of Art. 82 with regard to unity is met (see F-V).
The following are examples of typical situations falling within the scope of the exceptions from the principle of one independent claim per category:
For the purpose of Rule 43(2)(a), the term "interrelated" is interpreted to mean "different objects that complement each other or work together". In addition, Rule 43(2)(a) can be interpreted as covering apparatus claims, since the term "products" is considered to include apparatuses. Likewise, it may include systems, sub-systems and sub-units of such systems, as long as these entities are interrelated.
For the purpose of Rule 43(2)(c), the term "alternative solutions" can be interpreted as "different or mutually exclusive possibilities". Moreover, if it is possible to cover alternative solutions by a single claim, the applicant should do so. For example, overlaps and similarities in the features of the independent claims of the same category are an indication that it would be appropriate to replace such claims with a single independent claim, e.g. by selecting a common wording for the essential features (see F-IV, 4.5).