The down lead length of lightning protection belt is not less than 6d(d is the diameter of galvanized round steel), and it is welded on both sides. Double bolt fastening, no corrosion. According to the query of Dongguan Huayun Lightning Protection Engineering Co., Ltd., the length of down conductor of lightning protection belt is not less than 6d(d galvanized round steel diameter), and it is welded on both sides. Double bolt fastening, no corrosion. Lightning protection zone is a kind of lightning arrester, which is generally laid horizontally or obliquely (depending on the inclination of the roof). At least two places (the head end and the tail end) of the down conductor are connected with the down conductor, which is usually exposed, but can also be hidden under the concrete or tiles on the roof. In the latest edition of Code for Lightning Protection Design of Buildings (GB50057-20 10), the lightning protection zone is called lightning strike zone.