However, like the ground loop tester that Dereck mentioned, this method tests the resistance of the entire circuit, including the utility company's ground. If the fuse blows it does mean that your ground is less than 25 ohms, but if it doesn't blow, it doesn't necessarily mean your ground is over 25 ohms. It just means that the sum of the resistances of your ground, the utility company's ground, and the soil in between is 25 ohms or more.Originally posted by bphgravity:
One method is to connect a 5-amp fuse in series between a 120-volt "hot" conductor and the electrode itself. If the resistance is below 25-ohms, the 5-amp fuse will blow.