High Ground Rod Resistance

You should measure the resistance of an electrode with respect to the surrounding soil in the area.

High ground rod resistance. The nfpa and ieee recommend a ground resistance value of 5 ohms or less while the nec has stated to make sure that system impedance to ground is less than 5 ohms specified in nec 50 56. Step 1 connect your length of wire to a metal stake in the ground. To properly test the resistance of a ges you must follow some simple rules. You can only do this by using the fall of potential method with a three terminal earth ground resistance tester.

There is an increasing awareness in the electrical industry of the benefits of a low resistance high quality grounding system. Ideally a ground should be zero ohms of resistance but. The electrical code usa requires that a single ground rod have a maximum resistance to ground of 25 ohms nec 250 53 a 2. So if you are using 10 foot ground rods you must place.

If your ground rods are placed at least one rod length apart you can use a formula to estimate the earth resistance of multiple grounding rods. Unfortunately there is not one standard ground resistance threshold recognized by all certifying agencies. Multiple ground rods yield a lower resistance to ground than a single rod. This article takes a nuts and bolts approach to examining one the most commonly installed components.

Ground ring ground rods. In areas where codes require two ground rods because of high electrical resistance in the soil the rods must be spaced at least 6 feet apart and interconnected by a buried jumper wire. If this isn t met an additional ground rod is required but no resistance test is required. Make sure that you have stripped back the insulation from both ends of the wire to allow for a good connection.

Run the wire to your test location.