IEC 60794-2-51:2014 is a detail specification. It gives detailed requirements for cables to be used in cords which are intended for use in a category C environment, according to IEC 61753-1. They are characterized with temperature range between -10 °C and 60 °C. The fibre requirements for this specification are defined in IEC 60793-2-10 for multimode fibres and IEC 60793-2-50 for single-mode fibres. Some deviation to family specification IEC 60794-2-50 requirements is allowed in certain clauses of this specification. Keywords: requirements for cables, category C environment