8.7 Connecting the CRVW3 to earth ground
Electrical grounding of the CRVW3 station helps protect the hardware by mitigating against the
risk of nearby lightning strikes, static discharges, or other unexpected electrical conditions.
Connect the ground lug to an adequate earth/soil connection using a low-gauge wire (8 to
12 AWG) that accommodates high current flows.
Figure 8-7. CRVW3 ground lug location
A Basic Grounding Kit for Small Enclosures from Campbell Scientific can be used to make this
connection.
8.7.1 Electrostatic discharge protection
Electrostatic discharge (ESD) can originate from several sources, the most common and
destructive being lightning strikes. Primary lightning strikes are those that hit the CRVW3 or
sensors directly; secondary strikes induce a high voltage in power lines or sensor wires.
The CRVW3 must be properly earth grounded to take advantage of its built-in protection to
prevent damage from ESD. A good earth ground will minimize damage to the data logger and
sensors by providing a low-resistance path around the system to a point of low potential. All
components of the system (such as data loggers, sensors, external power supplies, mounts, and
housings) should be referenced to one common earth ground.
In the field, at a minimum, a proper earth ground will consist of a 5-ft copper-sheathed
grounding rod driven into the earth and connected to the large brass ground lug with a low-
gauge wire (8 to 12 AWG). In low-conductive substrates (such as sand, very dry soil, ice, or rock), a
single ground rod will probably not provide an adequate earth ground. For these situations,
search for published literature on lightning protection or contact a qualified lightning protection
consultant.
For information on the CRVW3 ESD testing, see
CRVW3 3-Channel Vibrating-Wire Data Logger
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