Emerson ControlWave Series Site Considerations For Equipment Installation, Grounding, And Wiring Manual page 13

3.3.1.2 Soil Types
Table 3-1
Table 3-1: Soil Types
Good
Damp Loam
Salty Soil or Sand
Farm Land
Always test ground beds for conductivity prior to placing any equipment in service. This section
provides a brief description of ground bed testing in both "good soil" and "poor soil." Details on
this test are described in the National Electrical Code Handbook. Once you establish a reliable
ground, test it routinely to preserve system integrity.
Figure 3-2
Figure 3-2: Basic Ground Bed Soil Test Setup
If the ground resistance testing unit (GRTU, such as a Meggar
Resistance Tester or an Associated Research Vibroground) reads less than 5 ohms, consider the
ground "good": the lower the resistance, the better the earth ground. If the GRTU reads more than
10 ohms, the ground is "poor." If a poor ground is indicated, drive one or more additional ground
rods connected 10 feet from the main ground rod into the soil and interconnect them via bare
AWG 0000 copper wire and 1" x ¼-20 cable clamps (as shown in
Grounding and Isolation
Site Considerations for Equipment Installation, Grounding, and Wiring Manual
details good and poor soil types.
shows the test setup for "good soil" conditions.
Poor
Back Fill
Dry Soil
Sand Washed by a Lot of Rain
Dry Sand (Desert)
Rocky Soil
®
D301452X012
September 2019
High-Performance Ground
Figure 3-3).
9