GB 50057-2010 第4.3.9条
| **** | **When multiple down conductors are used, a test joint shall be installed on each down conductor at a height of 0.3 m to 1.8 m above ground. When reinforcing steel in concrete or steel columns are used as natural down conductors together with foundation grounding electrodes, test joints may be omitted; however, when reinforcing steel is used as down conductors, several connection plates shall be provided at suitable locations indoors and outdoors.** |