12
2.4 Wiring
Power Connections
The Main Control Unit requires an AC power supply. See Figures 5 and 6 below.
The batteries forming the Battery Pack are wired in series. The Battery Pack attaches to the two wires
coming from the Power Supply Board, the black wire to the black (negative) terminal and the red wire to
the red (positive) terminal. The internal batteries are not used when an external battery box is used. The
wires for connecting the power supply board to the batteries are supplied with the panel if a battery box is
ordered at the same time.
Conventional Style B (Class B) Circuit
This is a 2-wire power-limited and supervised Style
B (Class B) initiating device circuit using
conventional normally open contact devices and an
end-of-line resistor, supported by the MR-2928
smoke and contact module. Maximum wire lengths
are shown in Table 2. The end-of-line resistor is a
470
Ω
resistor EOL-471. Devices and the end-of-
line resistor are connected as illustrated in Figure 7.
Warning:
Never connect or disconnect the batteries while the AC power is off.
Note:
2-wire smoke detectors cannot be used on this type of circuit. This circuit may be wired on any of
the 24 input circuits on the MR-2900 terminal boards.
Figure 5: 120VAC Power Connection
Figure 6: 240VAC Power Connection
EOL-471
Figure 7: Conventional Style B (Class B) Wiring
