[Weekend Share - 8] How to lap grounding flat steel, round steel, and angle steel?

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1. How should flat grounding steel, round steel, and angle steel be lapped? 【Answer】 I. According to Article 4.3.4 of GB 50169-2016 \"Code for Construction and Acceptance of Grounding Installations in Electrical Equipment Installation Projects\", when arc welding is used to connect grounding wires and grounding electrodes, lap welds shall be employed, and the lap length shall comply with the following requirements: 1. For flat steel, the lap length shall be 2 times its width, and at least 3 edges shall be welded together. 2. The round steel should be 6 times its diameter. 3. When connecting round steel and flat steel, its length should be 6 times the diameter of the round steel. 4. When welding flat steel to steel pipes or angle steel, in addition to welding on both sides of the contact area, it is also necessary to weld a steel strip or a clip bent from a steel strip to the steel pipe or angle steel. II. Article 22.2.2 of GB50303-2015 “Code for Acceptance of Construction Quality of Electrical Works in Buildings”: Lap welding shall be used for the welding of grounding devices. Except for weld joints buried in concrete, anti-corrosion measures shall be taken. The length of the welded lap joint shall meet the following requirements: 1. When flat steel bars are lap-welded, the overlap length shall not be less than twice the width of the flat steel bar, and welding shall be performed on at least three sides ； 2. The overlap between round bars should be no less than 6 times the diameter of the round bar, and welding should be performed on both sides ； 3. The overlap between round steel and flat steel should be no less than 6 times the diameter of the round steel, and welding should be performed on both sides ； 4. For welding flat steel to steel pipes or flat steel to angle steel, it should be in close contact with both outer sides of the angle steel, or with 3/4 of the pipe’s surface, with welding being carried out on the upper and lower sides. III. Article 8.8.5 of GB55024-2022 \"General Specifications for Building Electrical Systems and Intelligence\": When lap welding is used for grounding electrodes (wires), the lap length must comply with the following requirements: 1. For flat steel, the lap length should be no less than twice its width, and welding should be performed on at least three sides ； 2. The round steel should be no less than 6 times its diameter, and welding should be performed on both sides ； 3. When connecting round steel and flat steel, its length should not be less than 6 times the diameter of the round steel, and welding should be performed on both sides ； 4. The flat steel and steel pipe shall be welded tightly to the upper and lower surfaces of the 3/4-inch steel pipe; the flat steel and angle iron shall be welded tightly to the outer surfaces of both sides of the angle iron.