ELECTRICAL CONNECTIONS
4
13
SMARTPAT PH 8XXX
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04/2019 - 4004005203 - AD SMARTPAT PH 8xxx NEPSI R03
4.4 Grounding and equipotential bonding
To dissipate dangerous electrostatic charges the metal housing must be grounded. When
installing in pipes or vessels that are grounded, the electrical connection to earth is carried out
via the PG screw connection made of electrically conductive PEEK or metal
(SMARTPAT PH 8570).
If installing in pipes or vessels that are not grounded, the shield of the sensor cable must be
connected to the ground potential. The electrical connection to the metal housing and the
ground is made by the sensor cable with the VP connector.
When using junction box SJB 200 W-Ex, the shield of the sensor cable must be connected to the
shield connector provided for all SMARTPAT PH 8xxx. This will ensure sufficient electrostatic
grounding and at the same time prevent unacceptably high equalizing currents.
WARNING!
The cable shield must not be connected directly on both ends to the ground potential, since
unacceptably high equalizing currents can cause an explosion.
INFORMATION!
On junction box SJB 200 W-Ex, the shield connector is connected to the ground potential via a 1
megohms resistor and a capacitor in parallel.
The connections for the intrinsically safe 4...20 mA sensor circuit are galvanically isolated from
both the electrode circuit and the ground and can be considered ground-free (test voltage
500 V
eff
). It is accepted that the electrode circuit can be directly connected to the ground
potential.
