Home / Standards / NB/T 20049-2011 NB/T 20049-2011 Active 电缆贯穿挡火封堵件性能试验 Standard Type NB ICS N/A CCS N/A Status Active Issue Date 2011-07-01 Implementation 2011-10-01 Centralized Committee 国家能源局 Issuing Authority 国家能源局