A. Ground Rod:
16 mm diameter stainless steel. Driving head is to be high strength steel. Couplings are to be long length silicon bronze, internally threaded. Threads are to be rolled onto rod to ensure uniform layers of copper and strength. Earth rod is to be complete with non-corrosive couplings, head and bolted connector of sufficient size, and number of bolted clamps to connect all cables terminated thereto.
Minimum Length of Rod: 3.6 m, extendible as necessary to obtain required earth resistance. Rods, and driving caps and tips shall abut at couplings to ensure that the couplings and screw threads are not subject to driving forces. All screw threads shall be fully shrouded at the couplings.
B. Tape Mats:
Where earth rods are not likely to be used, earth electrode is to consist of parallel and perpendicular copper strip, 2.4 m apart, welded together by exothermic welds to form a grid. Tape is to be 25 x 2.5 mm strip conductor.
C. Earth Pit:
Precast, square or circular section concrete handhole (minimum 450 mm internal diameter), with ultra heavy-duty cover for areas where heavy vehicles cross, and extending to about 150 mm below top of earth rod. Earth pit is to be provided for each earth rod where connected to an earthing conductor. Earth pit body is to have inset stainless steel plate with inscription 'Earth Pit No. & Earth pit ID - Do Not Remove'.