Earth meter, 4325155, Fluke
The Fluke 1623-2 grounding meter makes it easy to measure ground loop resistances with current clamps. In this measurement method, two clamps are placed around the earth electrode and connected to the meter. No grounding spikes are used. A known fixed voltage is induced across one of the clamps, and the second clamp is used to measure the current. Then the meter automatically determines the resistance of the deep earth electrode. This method of measurement can only be used if a grounding system is connected to the building or structure being measured. However, this is usually the case. If, as in many residential areas, there is only one ground wire, the spikeless method will not yield an acceptable value, and the voltage drop measurement method must be used.
For the spike-less method, the earth rods do not have to be disconnected, so the connected grounding system remains intact during testing. The days of spending a tremendous amount of time placing and connecting spikes to each earth electrode in the system are finally over. It saves a lot of time. You can make grounding measurements in buildings, on utility poles, and anywhere that ground access is not possible.