Where the resistance of a single plate is higher than the required value, two or more plates may be used in parallel and the total resistance is than inversely proportional to the number employed, provided that each plate is installed outside the resistance area of any other. This normally requires a separation of about 10 m but for sizes of plate generally employed, a separation of 2 m is sufficient to ensure that the total resistance will not exceed the value obtained from the above formula by more than 20 percent. Even at the latter spacing, it is generally more economical to use two plates in parallel, each of a given size, than one of twice that size. The size employed is, therefore, normally not greater than 1·2 × 1·2 m. We, at Atul Casting and Metal Works manufactures all earthing related products such as G.I Strips, G.I plates, G.I Rods, G.I Pipes, C.I covers, Cable Trays, G.I Wire, Manhole Covers and Route Markers for past 50 + Years in heart of New Delhi. Call us at +91 9873361672 for best deals