From Annex 1 to Commission Regulation (EU) No 1178/2011 (as amended by Commission Regulation (EU) No 245/2014):
FCL.825 En route instrument rating (EIR)
(a) [..]
(b) [..]
(c) Training course. Applicants for an EIR shall have completed, within a period of 36 months at an ATO:
(1) at least 80 hours of theoretical knowledge instruction in accordance with FCL.615; and
(2) instrument flight instruction, during which:
(i) the flying training for a single-engine EIR shall include at least 15 hours of instrument flight time under instruction; and
(ii) the flying training for a multi-engine EIR shall include at least 16 hours of instrument flight time under instruction, of which at least 4 hours shall be in multi-engine aeroplanes.
etc