This part of IEC 60332 covers category B 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 to cables installed on the test ladder to achieve a nominal total volume of non-metallic material of 3,5 l/m of test sample. The flame application time is 40 min. The method of mounting uses the front of the standard ladder. The category is intended for general use where medium volumes of non-metallic material are required to be evaluated.