1200C-2000C Fire Alarm Control Panel, Repeater, and Black Box Installation Manual 39
Appendix D: Cable specifications
Mains power cable
The recommended mains cable is 3 x 1.5 mm² (live, neutral, earth).
Loop cable
A twisted pair cable is required to ensure data integrity. Shielded, fireproof cable is
highly recommended. If shielded cable is used, then cable shield continuity should be
observed.
Maximum cable length 2 km (cable Ø 1 mm)
Maximum cable capacitance 300 nF / km
Maximum total resistance 100
RS485 network cable
The recommended cable is CAT5 with a characteristic impedance of 100 .
Note: If the total cable length for the network exceeds 800 m and / or 32 nodes, we
recommend the use of fibre-optic cabling.
End-of-line termination resistors need to be used to match the cable characteristic
impedance to prevent reflections
Maximum cable length (bus and dual bus
topology)
800 m
Maximum number of nodes (bus and dual bus
topology)
32
When shielded cable is used, shields must be earthed at one point only. The shield of
the cable must be continued between nodes using the terminal provided on the card.
Fibre-optic network cable
The recommended fibre-optic cable is a straight tip (ST) duplex with a fibre width of
50/125, 62.5/125 or 100/140 µm.
Fibre-optic networks may use more than 32 nodes. The maximum distance between
nodes under ideal conditions is 1.7 km, but an optical power-budget calculation
should be performed to determine the correct maximum distance for each site.