Connection Between Polytron Se Ex Ht M Dq Sensing Head - Dräger Polytron SE Ex PR M1 DQ Notice D'utilisation

Installation & commissioning
4.2.2 Connection between Polytron SE Ex HT M DQ
sensing head and rack or transmitters
– With 3-wire, shielded line, shield braiding with 80% coverage. Max. outer
diameter: 12 mm.
– Select the cable in accordance with the planned usage temperature range.
– Only connect the shielding to the cabinet or switchboard earth when it is not
positioned to earth potential or equipotential bonding in or on the sensing
head.
Safety-related information on the cable gland
The cable gland is suitable only for fixed-location installation, and effective
strain relief or anti-twist protection of the cable should be provided.
The Peppers cable gland is intended for outdoor use in explosion-hazard areas
for non-armoured shielded cable. The shielding should not become caught up in
the gland and may therefore need to be laid separately in the housing. It is
suitable for normal industrial environments in terms of temperature, humidity
and vibration. Material compatibility relating to chemicals or aggressive
substances must be tested prior to installation. It should also be ensured that
the O-ring (1) is correctly seated.
5
3
Installing the sheathed line
The 3-wire shielded sheathed line is disconnected or stripped in accordance
with requirements (5) and inserted into the cable gland so that the cable sheath
remains in the cable gland (see figure). The press ring must reliably enclose the
cable sheath. Then screw the screw connection 3 into screw connection 2 using
two wrenches (3: M24, 2: M25). The correct torque for this is 25 Nm.
Double earthing can cause EMC problems. To avoid these problems, it is
necessary to connect the cable screen to earth potential on one side only; in the
central unit or on the sensing head. As the metallic sensing head housing with
its outer earth terminal has to be laid to earth potential or equipotential bonding
anyway, it is recommended in most cases to lay the shielding on the inner PE
terminal of the housing and not to lay the shielding in the central unit.
Safety-related information on the HT sensing head housing (High
Temperature, Range 2000 type)
The following details on the sensing head housing should be taken into account:
4 1
2