The utility model discloses a grounding switch includes the transfer line, install on the transfer line mechanism's case and with transfer line circumference sealing connection's rain -proof cap, rain -proof cap is located mechanism case top, still including the support frame that is used for supporting rain -proof cap, the lower surface butt of support frame and rain -proof cap, the support frame is installed on the transfer line. In the time of on rainwater descending to rain -proof cap, rain -proof cap rotates under transfer line rotation effect, and the rainwater is thrown away by the border of rain -proof cap under the effect of centrifugal force. Through setting up rain -proof cap in mechanism case top, and rain -proof cap and transfer line sealing connection, drive down at the transfer line, be convenient for throw away the rainwater around the transfer line, avoid the rainwater to flow in the condition of incasement portion of mechanism along the transfer line, consequently, the grounding switch's that this application provided life prolongs.