Product Manuals/Man-1088_Sigma XT_26 Page 13 of 40
6. Detection zone wiring
The detection zones provide a nominal 20V DC to power conventional detectors and call points as
listed in the compatibility tables 2 and 3.
The wiring is monitored for open and short circuit fault conditions by removing the 6K8 end of line
monitoring resistors that are supplied fitted to the control panels’ terminals and placing them
across the last device that is wired to the zone circuit.
Detection zone circuits must be wired as a single, radial circuit with no spurs or T junctions to
enable the monitoring circuit to work correctly.
For systems that are required to comply with BS5839 Part1:2002 detector removal requirements,
either detector bases fitted with a Schottky diode should be used and the end of line resistor
replaced with an LCMU active end of line monitoring device or zener clamping bases such as
Hochiki PA6 or Apollo Savwire used.
Figure 6. Detection zone wiring
7. Sounder circuit wiring
All sounders must be of the polarised type. If non-polarised sounders are used the control panel
will permanently show a fault condition. See table 4 for a list of compatible sounder types.
Sounder circuits are monitored for open and short circuit faults by placing a 10K end of line
monitoring resistor across the last device on the circuit.
Sounder circuits must be wired as a single, radial circuit with no spurs or T junctions to enable the
monitoring circuit to work correctly.
A maximum of 1.6 Amps is available for powering sounders with a maximum load of 0.5 Amps on
any one circuit.
Figure 7. Sounder circuit wiring
