Installation and Connections
37
8.8 Lightning Protection in HIMA Communication Systems
System earthing problems caused by a flash of lightning could be minimized due to the follow-
ing methods:
– complete shielding of the field wiring of HIMA communication systems
– correct installation of the system earthing.
In especially exposed environments outside of buildings it could be advisable to provide light-
ning protection by using special lightning protection modules. For this the module of type
MTRS 485 "DATA-MODUTRAB" from Phoenix company is used. The module is provided for
coarse protection (influences up to 10 kA) and fine protection (influences up to 400 A).
The connection of the lightning protection modules is according to the sketch below:
Figure 12: Connection of lightning protection tools
Planning notes:
The using of this lightning protection module reduces the max. possible transmission length
because of its series resistance of 4.4 Ω. Two modules are necessary per channel.
For HIBUS-2 the max. transmission length is 1200 m with 0.25 mm
2
wiring cross section. The
loop resistance is 180
Ω in this case (with regard of the specific line resistance of copper and
the double transmission length). The calculation of the remaining length of the bus refers on a
continuous wiring with the same cross-section according to the formula:
L
R
= ((180 Ω - n ∗ 4.4 Ω) / (2 ∗ R
L
)) ∗ 1000
L
R
= remaining length in m
n = number of line protection modules per channel
R
L
= line resistance in Ω/km
The result is a remaining length of 1141 m (2 modules, R
L
= 75 Ω/km) for 0.25 mm
2
cross sec-
tion.
8.9 Cable Colors
The system wiring of H41q/H51q specifies colors and color codes for cables and wires regard-
ing the relevant international standards.
Deviant from the HIMA standard the customer can also use different cable colors for wiring
based on national normative requirements. These deviations shall be documented and veri-
fied.
Note The line protection modules should not be installed in the same cabi-
net as the PES.
The use of fiber optics cable is advisable at large distances for light-
ning protection and protection of EMC influences.
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