IEC 61753-056-2:2012 contains the minimum initial test and measurement requirements and severities which a fibre optical fuse satisfies in order for it to be categorised as meeting the requirements of single mode fibre pigtailed style optical fuse used in controlled environments. Optical performance specified in this document relates to in-line type configurations fuses only. Keywords: initial test and measurement requirements, single mode fibre pigtailed style optical fuse