1995GB/T 3047.1-1995 Series of basic dimensions of panels, rack and cabinets for vertical increment of 20mm
1982GB 3047.1-1982 Series of basic dimensions of panels,racks and enclosures
GB 3047.1-1982 Series of basic dimensions of panels,racks and enclosures was changed to GB/T 3047.1-1995 Series of basic dimensions of panels, rack and cabinets for vertical increment of 20mm.