
Document #51003 Rev.E 01/11/02 P/N 51003:E
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Power Supply Calculations
Appendix A
Power Supply Calculations
A.1
The AC Branch Circuit
The MS-9200 requires connection to a separate dedicated 120 VAC branch circuit, which must be labeled Fire Alarm.
The branch circuit must connect to the line side of the main power feed of the protected premises. No other equip-
ment 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 Code as well as local codes. Use #14 AWG (2.00 mm
2
) wire with
600 volt insulation for this branch circuit.
Use Table A-1 to determine the total amount of current, in AC amps, that must be supplied to the fire alarm system.
TABLE A-1:
AC Branch Circuit Requirements @ 120VAC
Unit Type
Number of
Units
Current Draw
(amps)
Total Current
per Device
MS-9200(C)
or
MS-9200E
1
X
2.3
or
1.2
=
CHG-120F Charger
[ ]
X
2.0
=
Total AC Branch Current Required
=
amps