14
DCGear
P R O D U C T M A N U A L
3.4 Connection in plant
3.4.1 General criteria
The equipment and components used in the
DCGear panels are designed, manufactured and
assembled with specific criteria and measures,
to ensure the immunity of low-level circuits against
electromagnetic interference radiated or
conducted.
It 'also essential that the connections of the
plant, the arrangement of the cables and their
connections to the electric panel are carried
out according to specific rules, so as to ensure
the same immunity to signals from the field. For
this purpose, the electrical signals into and out
of the electric panel are divided into four levels,
as shown in Table 3.
The conductors relative to signals of different
levels must be arranged in separate ducts or in
metal conduit connected to earth. The distances
between the cable trays are shown in Table 4.
The recommended distances between pipes
connected to ground or between cable trays and
grounded ducts are half of those recommended
between the cable trays.
In addition, it is recommended to avoid long
stretches in parallel cable trays or tunnels related
to cables different level.
Any shielded cables must be installed by connecting
to ground the sheath of the screen at one end
only by the cable itself.
—
Table 2 – Torque
—
Table 3 – levels of electrical signals
—
Table 4 – distance between the different levels of cabletray
Hole
φ7
φ9-10
φ11
φ14
φ18
Type of screw
M 6
M 8
M 10
M 12
M 16
Torque Nm
7
20
40
70
120
Level
1
2
3
4
1
0
50 (2)
150 (6)
600 (24)
2
50 (2)
0
150 (6)
600 (24)
3
150 (6)
150 (6)
0
400 (16)
4
600 (24)
600 (24)
400 (16)
0
Level
1
2
3
4
Description
Analog and logic signals ≤50 Vdc or 24 Vac
Signs of shielded cables
Analog signals
＞
50 Vdc
Supplies≤50 Vdc or 28 Vac
Logic signals
＞
50 Vdc or 28 Vac
Supplies
＞
50 Vdc or 28 Vac
Control circuits for the coils of relays,
contactors, with auxiliary circuits ≤300Vac
(lighting, etc.)
Signals from instrument transformers of
current or voltage (TA-TV) or current shunts
(shunt) intended for instruments analog gauges
Power circuits
＞
200 Vdc and 300 Vac
Main circuits and power
mm (inc)
