IEC 61752-111-08:2021 contains the minimum tests, test severities and measurement requirements which a sealed fibre optic closure need to meet in order to be categorised as meeting the IEC standard for category G – Ground, as defined in Table A.14 of IEC 61753-1:2018. Free breathing closures are not covered in this document. This first edition cancels and replaces IEC 61753-111-8 published in 2009. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to IEC 61753-111-8: a) terms and definitions updated according to IEC 61753-1:2018 and IEC 61756-1:2019; b) test severities updated according to IEC 61753-1:2018; c) sealing tests are done with 20 kPa overpressure; d) pass-fail criterion of pressure loss during test added to mechanical sealing tests; e) vibration sealing test changed to 10 Hz, 3 mm amplitude and 1 000 000 cycles; f) reduced loads added in cable retention test for small diameter cables and tubes; g) reduced loads for cable axial compression test for small diameter cables; h) the duration of the cycles in torsion and bending test is added; i) free fall test removed (is covered by the optical shock test); j) crush resistance test of 1 000 N for 10 min is added; k) assembly and disassembly test: duration reduced to 5 cycles; l) resistance to solvents and contaminating fluids: added immersion in diesel with duration of 1 h and 24 h drying time and added immersion in petroleum jelly for 5 days; m) resistance to stress cracking solvents added for 5 days; n) duration of the change of temperature reduced to 12 cycles; o) water immersion test at 1 m for 7 days added.