A precast concrete ground rod box houses a copper-clad steel ground rod driven into the earth below. A cast iron ring seat and locking grade ring support a cast iron lid with hold-down screws, with the top of the ring set flush to grade and sealed in concrete. A minimum ten-foot by three-quarter-inch copper-clad steel ground rod connects to number four-slash-zero bare copper cable ground rings and lightning down conductors via typical mechanical connections. The ground ring must maintain a resistance of ten ohms or less, requiring additional driven rods as needed. The ground rod is offset within the precast body to accommodate clamp-on meter testing.
NOTES: 1. 2. THE GROUND RING GROUND RING OF THE FACILITY MUST HAVE A RESISTANCE OF 10 OHMS OR LESS. ADDITIONAL GROUND RODS MUST BE DRIVEN AS REQUIRED TO ACHIEVE THE PROPER RESISTANCE. INSTALL GROUND ROD OFFSET WITHIN PRECAST BODY TO ALLOW FOR CLAMP-ON METER CONNECTION. PROVIDE MINIMUM 10' x 3/4" COPPER- CLAD STEEL GROUND ROD GROUND RING, #4/0 BARE COPPER CABLE LIGHTNING DOWN CONDUCTOR GROUND RING #4/0 COPPER CABLE MECHANICAL CONNECTION (TYP) 18" (MIN) 12" (MIN) 20" (MIN) GROUND ROD CAST IRON LID, WITH HOLD DOWN SCREWS MOUNT TOP OF LOCKING GRADE RING FLUSH WITH GRADE AND SEAL WITH CONCRETE GROUND ROD BOX PRECAST CONCRETE BODY CAST IRON RING SEAT 2"
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