Note : Reference API 575; 7.2.5 Grounding Connection lnspection, Some tanks are provided with grounding connections.The grounding connections should be visually checked for intact connection and for corrosion at the point where they enter the earth or attach to a grounding rod and at the tank ground clip.If any doubt exists about the condition of the grounding connection, its resistance can be checked. The total resistance form tank to earth should not exceed approximately 25 ohms. Reference API RP 2003 provides information concerning the grounding of tanks to prevent ignition from static electricity, lightning strikes or stray electrical currents.