Power Supply Calculations Overview
126 IQ-301 PN 50036:F 10/29/2001
Appendix A Power Supply Calculations
A.1 Overview
This appendix contains instructions and tables for calculating power supply currents in
alarm and standby conditions. This is a four-step process, consisting of the following:
1. Calculating the total amount of AC branch circuit current required to operate the
system.
2. Calculating the power supply load current for non-fire and fire alarm conditions
and calculating the secondary (battery) load.
3. Calculating the size of batteries required to support the system if an AC power loss
occurs.
4. Selecting the proper batteries for your system.
A.2 Calculating the AC Branch Circuit
The control panel requires connection to a separate, dedicated AC branch circuit
(120 VAC for IQ-301 and 220/240 VAC for IQ-301E), which must be labeled FIRE
ALARM. This branch circuit must connect to the line side of the main power feed of
the protected premises. No other equipment may be powered from the fire alarm
branch circuit. The branch circuit wire must run continuously, without any disconnect
devices, from the power source to the fire alarm control panel. Overcurrent protection
for this circuit must comply with Article 760 of the National Electrical Codes as well as
local codes. Use 14 AWG wire with 600-volt insulation for this branch circuit.
Use Table 44 and Table 45 to determine the total amount of current, in AC amperes (A),
that must be supplied to the system.
Table 44 S120 VAC Branch Circuit Requirements
Table 45 220/240 VAC Branch Circuit Requirements
Device Type
(amps)
Number of
Devices Current Draw
Total
Current
per Device
IQ-301 1 X 3.0 = 3.0
AVPS-24 [ ] X 1.0 =
APS-6R [ ] X 2.5 =
Sum Column for AC Branch Current Required = A
Device Type
(amps)
Number of
Devices Current Draw
Total
Current
per Device
IQ-301E 1 X 1.5 = 1.5
AVPS-24E [ ] X 0.5 =
APS-6R [ ] X 1.2 =
Sum Column for AC Branch Current Required = A
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