Determining the Total Load Current
The following example demonstrates the process for determining the total load current of the Aura Fire Alarm
Control Panel:
1. Identify the current draw of each device on the circuit connection.
2. Add the device currents together in each circuit connection.
3. Compare the sum of the device currents with the current limit of each circuit connection to verify that the
summed level is below the current limit value.
4. Add the device load currents together that were obtained for each of the circuit connections:
Circuit Connection Maximum Current Limit Example Load Current
SLC Loop 1 400 mA 150 mA
SLC Loop 2 400 mA 50 mA
AUX 24V 900 mA 0
NAC 1 2.5 A 750 mA continuous DC
NAC 2 2.5 A 925 mA continuous DC
Total Device Load 1.875 A
5. Add the Total Device Load to the no-load alarm current to obtain the Total Load Current.
6. Total Device Load + Aura Fire Alarm Control Panel No-Load = Total Load Current
1.875 + 200 mA = 2.075 A
Total Load Current = 2.075 A
7. Verify that the current level is below 4 Amps: 2.075 A < 4 A
8. This example demonstrates that device loading does not exceed the 4 Amp capacity of the power supply.
1.25 A of the 5.25 A power supply is reserved for battery charging.
Refer to Specifications for the maximum current limits provided in the example calculation above.
SHIELD Fire, Safety & Security Ltd
Aura Fire Alarm Control Panel Installation Manual
Version 1.00 | June 2019 | MAN-1431VS
Page 143
Appendix C: Calculations
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