Ground Rod Resistance Test

Check your clamp on tester s manual if it uses another kind of configuration.

Ground rod resistance test.

For example the national electric code requires no greater than 25 ohms of resistance in a ground system. Unfortunately as time goes by factors such as ground rod corrosion soil moisture high salt content high temperatures and loss of contact of your wires as well as others may increase the resistance of ground rod s hence affecting its effectiveness. Built to withstand an entire spectrum of ground testing methods fluke s family of earth ground testers have been designed to be accurate safe and easy to use. Ideally a ground should be zero ohms of resistance but.

Step 1 connect your length of wire to a metal stake in the ground. Check errant current flow to ground for operator safety and give an overview of ground system dynamics. Test the resistance of a single rod in a series or array. If this is the case for your ground rod the best solution is to drive a different rod into a different location.

For a safe electrical system your ground rod resistance should have a very low resistance value. Run the wire to your test location. To properly test the resistance of a ges you must follow some simple rules. Unfortunately there is not one standard ground resistance threshold recognized by all certifying agencies.

Make sure that you have stripped back the insulation from both ends of the wire to allow for a good connection. Ground ring ground rods. So if you are using 10 foot ground rods you must place. An ideal ground rod resistance should be below 3 ohms.

You should measure the resistance of an electrode with respect to the surrounding soil in the area. 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. The lower it is the better job it does. Multiple ground rods yield a lower resistance to ground than a single rod.

For instance if a ground rod is driven into a very rocky and dry area it may not conduct electricity into the ground well. With this method the resistance of two electrodes in a series is measured by connecting the p1 and c1 terminals to the ground electrode under test. Step 5 measure the ground or leakage current if you wish to find out about the ground or leakage current all that you have to do is to set the rotary switch to ma or a. P2 and c2 connect to a separate all metallic grounding point like a water pipe or building steel.

You can only do this by using the fall of potential method with a three terminal earth ground resistance tester. However we can estimate the resistance to ground using scenario b. In areas where driving ground rods may be impractical the two point method can be used. 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.