ABB FEX300, Operating Instruction

Page: 37 / 176

Mounting
OI/FEX300/FEX500-EN FEX300, FEX500 37
4.7.9 Installation and grounding in pipelines with cathodic corrosion protection (CCP)
The installation of electromagnetic flowmeters in systems with cathodic corrosion protection
must be made in compliance with the corresponding system conditions. The following factors
are especially important:
a) Pipelines inside electrically conductive or insulating.
b) Pipelines completely or for the most part with cathodic corrosion protection (CCP) or mixed
systems with CCP areas and PE areas.
• When installing an EMF in pipes with insulating inner lining and free from foreign matter, it
should be insulated with grounding plates on the upstream and downstream side. The CCP
potential is diverted. The grounding plates upstream and downstream of the EMF are
connected to functional ground (Fig. 29 / Fig. 30).
• If the occurrence of external stray currents is to be expected in pipelines with internal
insulation (e.g. in the case of long pipe sections in the vicinity of power supply units), an
uninsulated pipe of approx. 1/4 DN of length should be provided upstream and downstream
of the flowmeter sensor in order to deviate these currents away from the measuring system
(Fig. 31).
4.7.9.1 Internally insulated pipelines with cathodic corrosion protection potential
Fig. 29: Bolt screw view
1

Pipe flange
2

Insulating plate
3

Gasket / insulating ring
4

Grounding plate
5

Insulating pipe
6

Insulating plate
7

Flange
8

Lining
9

Insulation
10

Flowmeter sensor
Install grounding plates on each side of the flowmeter sensor. Insulate the grounding plates
from the pipe flanges and connect them to the flowmeter sensor and to functional ground.
Insulate the screw bolts for the flange connections when mounting. The insulation plates and
the insulation pipe are not included in the delivery. They must be provided onsite by the
customer.