A board may only refer a point of law to the Enlarged Board of Appeal "during proceedings on a case" (Art. 112(1)(a) EPC). If the underlying appeal is withdrawn (see T 1040/04 and G 3/06[no decision thus no link], OJ 2007, 312), or the underlying application deemed to be withdrawn (G 2/14[no decision thus no link], OJ 2015, A13), the proceedings before the Enlarged Board are terminated.

The referral to the Enlarged Board must precede the decision of the board of appeal (T 2271/08). After a board has issued a decision in respect of certain issues, it has no power to refer a question to the Enlarged Board in connection with the issues already decided, even though other issues are still pending in proceedings on the same case (T 79/89, OJ 1992, 283).

For a referral to be admissible, the appeal has to be admissible (see T 1954/14). This principle does, however, not apply if the referral itself concerns the admissibility of the appeal. Without this exception, the boards would be denied the opportunity to refer questions on important points of law concerning the admissibility of an appeal. This would contradict Art. 112(1)(a) EPC where no restrictions of that kind appear (G 1/12, OJ 2014, A114; see also G 8/92, not published in the OJ; G 3/99, OJ 2002, 347; G 2/90, OJ 1992, 10 and G 2/04, OJ 2005, 549).