Edwards Signaling EBPS Remote Booster Power Supply - Manual (Page 46)

40 Remote Booster Power Supply Technical Reference Manual
Equation method
Appliance operating voltage and current
Regulated notification appliances have an operating range from 16 V to 33 V.
Use 16 V as the minimum appliance voltage when using regulated notification
appliances.
When using special application appliances, refer to the installation sheets to
determine the minimum appliance voltage required.
What if there are different types of appliances in the NAC, and each type has a
different minimum operating voltage? In this case, use the highest minimum
voltage required by any appliance.
The total current requirement for the appliances will be the sum of the individual
maximum currents drawn by each appliance when using DC power. Use the
maximum current for the appliance over the 16 V to 33 V range.
If all appliances draw the same maximum current, the total current is the
maximum current multiplied by the number of appliances. If different appliance
types have different maximum currents, the total current is the sum of the
maximum current for each appliance type multiplied by the number of appliances
of that type.
Wire resistance
Typical wire resistances are shown in the following table.
Table 11: Typical wire resistances
Wire
gauge
(AWG) Resistance
Solid uncoated copper Resistance
Stranded uncoated copper
Ω per foot Ω per meter Ω per foot Ω per meter
12 0.00193 0.00633 0.00198 0.00649
14 0.00307 0.01007 0.00314 0.01030
16 0.00489 0.01604 0.00499 0.01637
18 0.00777 0.02549 0.00795 0.02608
Note:
When performing these calculations, always refer to the actual cable
supplier documentation and use the actual Ω/ft (or Ω/m) at the appropriate
temperature for the cable being used.