Mounting
24 - EN
FEX300, FEX500
CI/FEX300/FEX500-EN
4.6
Ground
4.6.1 General information on ground connections
Observe the following items when grounding the device:
• For plastic pipes or pipes with insulating lining, the ground is provided by the grounding plate
or grounding electrodes.
• When stray potentials are present, install a grounding plate upstream and downstream of the
flowmeter sensor.
• For measurement-related reasons, the potentials in the station ground and in the pipeline
should be identical.
• An additional ground on the terminals is not required.
Important (Note)
If the flowmeter sensor is installed in plastic or earthenware pipelines, or in pipelines with an
insulating lining, transient current may flow through the grounding electrode in special cases.
In the long term, this may destroy the sensor, since the ground electrode will in turn degrade
electrochemically. In these special cases, the connection to the ground must be performed
using grounding plates. Install a grounding plate upstream and downstream of the device in
this case.
4.6.2 Metal pipe with fixed flanges
Use a copper wire (at least 2.5 mm² (14 AWG)) to establish the ground connection between the
sensor (1), the pipeline flanges and an appropriate grounding point.
G00662-01
1
1
„A“
Flange design
Wafer type design
Fig. 21: Metal pipe, without lining (example)
"A" Grounding in the case of a plastic terminal box (ProcessMaster only)
Important (Note)
• Grounding is illustrated using the example of the dual-compartment transmitter housing; in
the case of transmitters with single-compartment housing, grounding is to be performed as
shown.
• In the case of flowmeter sensors with plastic terminal boxes, perform grounding as shown
in "A".
