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1.3 Electrical connection of separate primary head (F Versions)
1.3.1 General information on signal cable A and field current cable C
Use of the Krohne signal cable A with foil screen and magnetic shield will ensure proper operation
of the equipment.
• Signal cable to be solidly laid.
• Connect shields via stranded drain wires.
• Underwater and underground installation possible.
• Insulating material is flame-retardant to IEC IEC 332.1 / VDE 0742.
• Signal cables are low in halogen, unplasticized, and stay flexible at low temperatures.
Signal cable A (Type DS), with double shielding
1
Stranded drain wire, 1st shield, 1.5 mm
2
or AWG14
2
Insulation
3
Conductor 0.5 mm
2
or AWG 20 (3.1 red / 3.2 white)
4
Special foil, 1st shield
5
Inner sheath
6
Mu-metal foil, 2nd shield
7
Stranded drain wire, 2nd shield, 0.5 mm
2
or AWG 20
8
Outer sheath
Field current cable C with single shielding
Cross-section is dependent on required length of cable, see Table in Sect. 1.3.4.
1.3.2 Grounding of primary head
All flowmeters must be properly grounded.
• The grounding conductor should not transmit any interference voltages.
• Do not ground any other electrical device together with this conductor.
• The primary head is connected to ground by means of an FE functional ground conductor.
• Special information on grounding various primary heads is contained in the separate
installation instructions for primary heads.
• These instructions also contain detailed descriptions on how to use grounding rings and
how to install primary heads in metal or plastic pipes or internally coated pipelines.
