Ground Rod Resistance Check

P2 and c2 connect to a separate all metallic grounding point like a water pipe or building steel.

Ground rod resistance check.

Run the wire to your test location. 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. Multiple ground rods yield a lower resistance to ground than a single rod. Check your clamp on tester s manual if it uses another kind of configuration.

R loop 10 ω 0 17 ω 10 17 ω. 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. Unfortunately there is not one standard ground resistance threshold recognized by all certifying agencies. For instance if a ground rod is driven into a very rocky and dry area it may not conduct electricity into the ground well.

Step 1 connect your length of wire to a metal stake in the ground. In some instances ground rods can be installed in areas where the earth has a lot of resistance. You should measure the resistance of an electrode with respect to the surrounding soil in the area. Ground ring ground rods.

The lower it is the better job it does. 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. In areas where driving ground rods may be impractical the two point method can be used. For a safe electrical system your ground rod resistance should have a very low resistance value.

For example the national electric code requires no greater than 25 ohms of resistance in a ground system. An ideal ground rod resistance should be below 3 ohms. To properly test the resistance of a ges you must follow some simple rules. Ideally a ground should be zero ohms of resistance but.

So if you are using 10 foot ground rods you must place. The measurement of the loop resistance is relatively close to the resistance of the ground electrode being tested. Make sure that you have stripped back the insulation from both ends of the wire to allow for a good connection. 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.

However we can estimate the resistance to ground using scenario b. If there were 60 similar ground electrodes with a resistance of 10 ω each the measurement of the total loop resistance would be.