4.0 INSTALLATION
4-4
Cheetah Xi 50 Installation Manual
UL S2203
Rev 6, 09/2015
P/N: 06-369
FM
4.6
CIRCUIT CLASS DESIGNATIONS
The circuits on the Cheetah Xi 50 controller and its field devices can be configured for Class B (two wire) or
Class A or X (four wire) operation. Class B wiring does not include a redundant path and the operational
capability stops at a single open. Class A wiring includes a redundant path and the operational capability
continues past a single open. When Class A wiring is utilized, no t-tapping is allowed and the return leg from
the last device on the circuit back to the panel or device must be run in a separate conduit from the main leg.
With Class A wiring, the control panel is constantly supervising all wiring (both main and redundant). Once an
open fault is detected on either leg, the panel immediately transfers communication to the intact redundant leg
of the Class A wiring. Class X wiring is the same as Class A wiring, but requires the use of isolator devices in
order to provide operational capabilities past a single open or short-circuit.
4.7
PULL FIELD WIRING INTO THE ENCLOSURE
The Cheetah Xi 50 system wiring is classified as either power-limited or non-power-limited per NEC article
760. All power-limited wiring must be separated from all non-power-limited wiring by a minimum distance of
1/4 inch (6 mm) within the system enclosure. The Cheetah Xi 50 power-limited versus non-power-limited
circuits are designated as follows:
Power-Limited circuits include:
P2 – Relays (Alarm, Supervisory, Trouble)
1,2
P3 – Computer Interface Connection
P4 – VESDA HLI Interface
P5 – Not Used
P6 – RS-485 Peripheral Buss, DACT, AUX Power
P7 – Signaling Line Circuit
P8 & P9 – Notification Appliance Circuits (1 & 2)
1
Connected to power-limited or nonpower-limited field wiring, but not
both.
2
When the optional DACT module is installed, the incoming phone
lines (power-limited) must be separated from any nonpower-limited
P2 relay connections.
Nonpower-limited circuits include:
P1 – AC Power Supply Input and Battery Input
P2 – Relays (Alarm, Supervisory, Trouble)
1,2
When installing optional components within the Cheetah Xi 50 enclosure, refer to the installation instructions
supplied with each component for designation of power-limited versus non-power-limited circuits. Route all
field wiring through the appropriate conduit knockouts, then to the appropriate circuit terminals. Provide
adequate wire length to allow strain relief.
4.8
VERIFY FIELD WIRING
The integrity of the field wiring shall be tested before installing field devices or landing the field wiring to the
system controller. With the end of each circuit open, the following tests shall be conducted:
1. Verify absence of ground-fault on any field wiring prior to connecting the circuits. Refer to
specifications for acceptable readings.
2. Verify no stray voltages exist on any field wiring prior to device installation.
3. Verify each conductor is free from shorts between all other conductors and chassis.
4. Measure wire resistance with a short across the circuit at a point furthest from circuit start. This is
typically across EOL for Class B and at the panel for Class A or Class X.
I
Caution
Field devices must not be connected if using a meggar or any
means that applies voltages in excess of device ratings to
prevent damage to the devices.
Summary of Contents for 10-071
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