FL-PS Series Instruction Manual —
P/N LS10227-001FL-E:B 3/29/2021
33
Section 6: Power Supply Requirements
6.1 Overview
This section 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 secondary non-fire and fire alarm conditions
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
6.2 Calculating the AC Branch Circuit
The power supply requires connection to a separate, dedicated AC branch circuit, 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 non-fire alarm equipment may be pow-
ered from the fire alarm branch circuit. The branch circuit wire must run continuously, without any disconnect devices, from the power
source to the power supply. Overcurrent protection for this circuit must comply with Article 760 of the National Electrical Codes as well
as local codes. Use a minimum of 14 AWG (2.00 mm
2
) wire with 600 volt insulation for this branch circuit.
Use Table 6.1 to determine the total amount of current, in AC amperes, that must be supplied to the system.
6.3 Calculating the System Current Draw
6.3.1 Overview
The power supply must be able to power all internal and external devices continuously during a fire alarm condition. The secondary
power source (batteries) must be able to power the system during a primary power loss.To calculate the non-fire alarm load on the power
supply when secondary power is applied, use Calculation Column 1 in Table 6.3 on page 34. The power supply must support a larger
load current during a fire alarm condition. To calculate the fire alarm load on the power supply as secondary power, use Calculation Col-
umn 2 in Table 6.3 on page 34.
When calculating current draw and the battery size, note the following:
•
Primary
refers to the main power source for the power supply.
•
Secondary
refers to the power supply’s backup batteries.
•
All currents are given in amperes (A). Table 6.2 shows how to convert milliamperes and microamperes to full amperes.
Device Type
Number of
Devices
Current Draw
(AC amps)
Total Current
per Device
FL-PS6(C)
or
FL-PS10(C)
1
x
5.0
or
6.2
=
[ ]
[ ]
x
[ ]
=
[ ]
[ ]
x
[ ]
=
Sum Column for AC Branch Current Required
=
Table 6.1 120 VAC Branch Circuit Requirements
To convert...
Multiply
Example
Milliamperes (mA) to amperes (A)
mA x 0.001
3 mA x 0.001 = 0.003 A
Microamperes (
μ
A) to amperes (A)
μ
A x 0.000001
300
μ
A x 0.000001 = 0.0003 A
Table 6.2 Converting to Full Amperes
