The  national standard for the classification of domestic cable and cable  combustion performance was officially implemented on September 1, 2015:
The  new national standard GB 31247 – 2014 “Cable and Cable Combustion  Performance Grading” not only assesses the carbonization height of the  cable, but also requires an assessment of the cable's heat release and  smoke production characteristics. The  traditional structure of the flame-retardant cable is difficult to pass  the GB 31247-2014 combustion performance classification B1 level due to  the more combustible materials in the various components of the cable  and no good isolation measures. The  isolated flame-retardant cable technology has been upgraded and passed  the B1 level assessment. It is believed that it will soon be widely  used.
The  national standard GB 31247 – 2014 “Cable and Optical Cable Combustion  Performance Grading” will be officially implemented on September 1,  2015. The standard is based on international standards, and the flame  retardant level is changed from the original A, B, C, D grades. A, B1, B2, B3. Class  A is non-combustible, that is, the cable with outer sheath is metal  sheath, such as MI cable; B3 is not flame retardant type, such as VV,  YJV, etc.; B1 and B2 are the most applicable flame retardant cables. According  to the importance of the place of use, high-rise buildings and crowded  places should choose B1 flame-retardant cables. The EU CPR regulations  have clearly mandated that buildings use flame-retardant cables with  specified flame-retardant grades, which are expected to be followed up  and implemented in China. The  grading standard redefines the flame retardant level, puts forward new  requirements for cable flame retardancy, and puts forward new  requirements for cable manufacturing and design selection.