The diagram can be seen in the graphic symbols involving the grounding device there are four, as follows:
One, this is to indicate that the grounding busbar, the diagram here there is no structural ground beams as a natural grounding body, only the use of -50 × 5 hot-dip galvanized flat steel to do artificial grounding body.
Second, this symbol indicates that from the top of the lead, here indicates that the lightning protection grounding lead, is the use of building reinforcement for the lead.
Three, this symbol indicates that the grounding, sometimes in the lightning protection grounding system indicates that there is a test point, specifically look at your construction drawings on the legend.
Four, the letters in the circle indicate the grounding test point number or bit number.