A ground lug is provided on the inside rear enclosure. Additionally, a ground wire should be attached from any available screw in the front enclosure housing to the rear enclosure lug. Then a ground wire from the rear enclosure lug to earth ground. This will provide a path for lightning and static electricity. A proper Earth Ground Rod must be installed to ensure proper grounding and prevent damage to keypads. You should use 1 ground rod for each keypad.