INSTALLATION
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Manual EC 24 · EN05 · 2015-02
10
If one or more than one circuit is used, make sure that the permissible limit values in accordance
with the EC type approval certificate are not exceeded.
Each intrinsically safe signal circuit must be installed in a separate cable which is to be taken
through an appropriate high-strength cable gland.
It is absolutely imparative that the intrinsically safe cables are permanently installed.
Make sure that the connecting cables are provided with core-end sleeves.
Earthing
To prevent measuring errors caused by electromagnetic interference, you
must not fail
to earth the
case of the meter head via the earthing screw on the left side of the case.
Cables
Use 2-core or multicore shielded cables which are twisted together in pairs (type LIYCY) for the
signal lines (LF output, HF output, current-loop connection, control input).
Use 4-core shielded cables which are twisted together in pairs (type LIYCY) for the data lines (RS
485).
The shielding must always be connected to earth on both sides. In the case of the EC 21 / EC 24 ,
you must proceed as described under “Cable glands”.
We recommend that cable cross sections of 0.5 mm
2
are used. Due to the cable gland, the outside
diameter must be between 4.5 mm and 6.5 mm.
If the device is used in areas subject to explosion hazards, the maximum cable length is limited by
the limit values for intrinsically safe circuits and depends on the inductance and capacitance of the
cable!
Minimum cable cross section:
Up to a length of 10 m:
6 mm
2
From a length of 10 m: 10 mm
2
Earthing screw
Calibration switch
