Installation Installation of Optional Modules

26 MS-2/MS-4 PN 51512:E 01/18/05

2.6.1.2 Wiring NACs and IDCs for Class A

Wire the Style Z (Class A) Notification Appliance Circuits using TB2 of the MS-4

and TB1 of the CAC-4 module. Wire the Style D (Class A) Initiating Device

Circuits using TB3 of the MS-4 and TB1 of the CAC-4. Make certain to observe

polarity when connecting the devices to the circuits. The B+ and A+ terminals must

comprise the feed and return for the positive side of a device and the B- and A-

terminals must comprise the feed and return for the negative side of a device. To

configure any of the zones for Class B when the CAC-4 is installed, simply wire to

the B+ and B- input on the FACP terminal(s) and install the End-of-Line Resistor

after the last device on the circuit. Do not wire to the corresponding A+ and A-

terminals on the CAC-4 module. Note that Zone 1 IDC on the MS-2 and Zone 2

IDC on the MS-4 can be configured as a combination waterflow/supervisory circuit

as illustrated in the following figure.

TB3TB2B+ B- B+ B- NAC 1 NAC 2B+ B- B+ B- ZONE 1 ZONE 2B+ B- B+ B- ZONE 3 ZONE 4TB1
A+ A- A+ A-

NAC 1 NAC 2

CLASS A CLASS A
A+ A- A+ A-

ZONE 1 ZONE 2

CLASS A CLASS A
A+ A- A+ A-

ZONE 3 ZONE 4

CLASS A CLASS A

Figure 2.11 Wiring NACs and IDCs for Class A Operation

CAC-4 Class A Converter Module

MS-4

Circuit Board

Class B (Style B)
IDC - 4.7 K
½ watt ELR
resistor
P/N:71252
(supervised and
power-limited)
Dummy load all unused
circuits - 4.7 K
½ watt ELR resistor
(P/N: 71245)
Polarized
Bell
Circuit polarities
shown in alarm
condition
Class A (Style Z) NAC
(supervised and power-limited)
Class A
(Style D) IDC
(supervised and
power-limited)
Class A
(Style D) IDC
Combo Waterflow
& Supervisory
20K, ½ watt ELR
resistor P/N:75477
(supervised and
power-limited)
1.2 K
½ watt
In-Line
resistor
P/N:75579
Polarized
Strobe
Polarized
Horn
Tamper
Tamper
Waterflow
Smoke Smoke
Pull Station
Pull Station
Heat
Heat
IMPORTANT!
All devices must be
within 20 feet of the
Class A portion of
the circuit and
wiring must be in
conduit.
ms4comba.cdr