Technical/Programming Manual
FT1020G3 Rev 2.2.1
169
When feeder line is required, use suitable multi core twisted pair cable 1.5mm
2
. Refer to
Note:
Addressable Alarm devices e.g. 3379, 4477, etc. are connected directly on the
COM loop.
25.6
Other equipment cables
Intrinsically safe equipment for hazardous areas, RIL, MDH, etc, recommended cable
Brooks BAC0898
1.5 mm
2
twin TPS or equivalent.
The maximum cable length and maximum COM loop current, are dependent on the number
and type of loop units and the type of cables used. The cable length for a COM loop is the
total cable length from the CIE and returning back to CIE thus completing the loop.
Since the COM loop cable length is dependent on the number of units and their current
consumption the figure in the table is for the maximum number of COM loop units i.e. 255
units and 350mA.
Table 14 below summarises the different cable types required and the maximum cable
length allowed.
Table 14 Summary of Recommended Cables
Connection type
Cable type
Conductive
surface area
Resistance/km
Cable
length
Com Loop
Twisted pair
1.5mm
2
11.9
Ω/km
1300m
Conventional Zone
Flat pair
1.5 mm
2
11.9
Ω/km
1000m
1mm
2
24 Ω/km
650m
Alarm Devices
Flat pair
1.5 mm
2
11.9
Ω/km
1000m
1mm
2
24 Ω/km
650m
Display Units (RS485)
CAT5 for data
0.5 mm
2
0.5 mm
2
1200m
Twisted pair for power 1-1.5 mm
2
1-1.5 mm
2
1200m
Other cables
Flat pair
1mm
2
24 Ω/km
650m