The national standard for insulating rubber board is HG2949-1999 "Electrical insulating rubber pad?" . The standard specifies the classification and requirements of insulating rubber sheets, as follows: Color classification: including red, black, green, gray, etc. Voltage classification: divided into 5KV, 10KV, 15KV, 20KV, 25KV, 30KV, 35KV. Thickness classification: 3mm, 5mm, 8mm, 10mm, 12mm...