The down lead is an important component of external lightning protection devices, and its connection directly affects the safety of external lightning protection. In conventional lightning protection testing, there are many requirements for down lead detection. Today, Lianya Testing will share with you the precautions for lightning protection testing of down conductors in conjunction with relevant technical specifications 1. Check if the position of the specially designed down lead is correct 2. Check whether the fixed welding seam is full without omission, whether the rust prevention of the welding part is complete, and whether the interface of the specially designed down lead is corroded by more than one-third 3. Check whether the down lead is flat, straight, and without sharp bends, and whether the clips are fixed in sections 4. Whether the spacing between the fixed brackets of the down lead is uniform and meets the requirements of 0.5 meters to 1 meter for horizontal or vertical straight parts and 0.3 meters to 0.5 meters for curved parts. Each fixed bracket should be able to withstand a vertical tensile force of 49 N 5. Check if the welding points of the specially designed down conductors, lightning arresters, and grounding devices are rusted, if there are any omissions in the paint, and if there are protective facilities near the ground 6. Check the electrical connection performance of each specially designed down lead and lightning arrester, and the excessive resistance should not exceed 0.2 ohms 7. Check if there are any attached electrical and electronic circuits on the dedicated down lead. Measure whether the distance between the specially designed down lead and nearby electrical and electronic circuits meets the requirements of technical specifications 8. Check whether the setting of the disconnection card for the specially designed down lead meets the provisions of the lightning protection technical specifications. When measuring ground resistance, disconnect the disconnect card at least once a year. The specially designed down lead is connected to the circular grounding body, and the grounding resistance cannot be disconnected when measuring the grounding resistance 9. Check whether the protection of the specially designed down lead near the ground that is prone to mechanical damage meets the requirements of lightning protection technical specifications 10. Use an instrument to measure the electrical connection performance between the grounding terminal of the specially designed down lead and the grounding body, and the excessive resistance should not exceed 0.2 ohms 11. Check whether the anti contact voltage measures comply with the provisions of the lightning protection technical specifications