This part of IEC60332 covers categoryD for methods of test for the assessment of vertical flame spread of vertically mounted bunched wires or cables, electrical or optical, under defined conditions. This document relates only to small cables of overall diameter 12mm or smaller and cross-section of 35mm 2 or smaller installed on the test ladder to achieve a nominal total volume of non-metallic material of 0,5l/m of test sample. The flame application time is 20min. The method of mounting uses the front of the standard ladder in touching formation only. The category is intended for use with small cables where very low volumes of non-metallic material are required to be evaluated. The test is intended for type approval testing. The requirements for the selection of cables for testing are given in AnnexA. The flame spread is measured as the extent of damage of the cable sample. This procedure can be used to demonstrate the cable’s ability to limit flame spread. A recommended performance requirement is given in AnnexB. NOTE For the purposes of this document the term \'electric wire or cable\' covers all insulated metallic conductor cables used for the conveyance of energy or signals.