Emerson ControlWave EFM 4710A Instruction Manual page 271

ground has been established, it should be tested on a regular basis to preserve system
integrity.
Figure 3-2 - Basic Ground Bed Soil Test Setup
Figure 3-3 - Basic Ground Bed Soil Test Setup with Additional Ground Rods
Figure 3-2 shows the test setup for 'Good Soil' conditions. If the Megger* reads less than 5
ohms, the ground is good. The lower the resistance, the better the earth ground. If the
Section 3 - Grounding & Isolation Page 3-3 S1400CW