Connection Procedure - Vega VEGAPULS 66 Operating Instructions Manual

5 Connecting to power supply
Cable glands
Cable screening and
grounding
22
Metric threads
In the case of instrument housings with metric thread, the cable
glands are screwed in at the factory. They are sealed with plastic
plugs as transport protection.
You have to remove these plugs before electrical connection.
NPT thread
In the case of instrument housings with self-sealing NPT threads, it is
not possible to have the cable entries screwed in at the factory. The
free openings for the cable glands are therefore covered with red dust
protection caps as transport protection.
Prior to setup you have to replace these protective caps with ap-
proved cable glands or close the openings with suitable blind plugs.
On plastic housings, the NPT cable gland or the Conduit steel tube
must be screwed into the threaded insert without grease.
If screened cable is required, we recommend connecting the cable
screen on both ends to ground potential. In the sensor, the screen
must be connected directly to the internal ground terminal. The
ground terminal on the outside of the housing must be connected to
the ground potential (low impedance).
In Ex systems, the grounding is carried out according to the installa-
tion regulations.
In electroplating plants as well as plants that apply cathodic corro-
sion protection, it must be taken into account that significant potential
differences exist. This can lead to unacceptably high currents in the
cable screen if it is grounded at both ends.
Information:
The metallic parts of the instrument (process fitting, housing, etc.) are
conductively connected to the ground terminal.
Take note of the corresponding installation regulations for Ex applica-
tions. In particular, make sure that no potential equalisation currents
flow over the cable screen. In case of grounding on both sides this
can be achieved by the use of a capacitor or a separate potential
equalisation.
5.2

Connection procedure

Proceed as follows:
1. Unscrew the housing lid
2. If a display and adjustment module is installed, remove it by turn-
ing it to the left
3. Loosen compression nut of the cable gland and remove blind
plug
4. Remove approx. 10 cm (4 in) of the cable mantle, strip approx.
1 cm (0.4 in) of insulation from the ends of the individual wires
5. Insert the cable into the sensor through the cable entry
VEGAPULS 66 • 4 ... 20 mA/HART - two-wire