Alpha Technologies CXDS-M 600_600-19 - Manual (Page 21)

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9400002-J0 Rev A
5. Installation - DC and Grounding Cables
This section provides cabling details and notes on cable sizing for DC applications with respect to the Alpha
CXDS-M -48/24 V modular distribution.
• Only qualified personnel should install and connect the power components within the Alpha power system.
• All wiring must be in accordance with applicable electrical codes.
• Electrical codes require that conductors carrying AC current be installed separately from conductors carry-
ing DC current and signals.
5.1 Installation Notes
5.1.1 Installer Responsibility
The system arrives pre-wired, and the installer is responsible for connecting the following:
• DC input to the system
• System to the load
• Chassis and battery return to the reference ground
• Alarms
5.1.2 Calculating Output Wire Size Requirements
Although DC power wiring and cabling in telecommunication applications tend to ex-
ceed electrical code requirements, mostly due to the voltage drop requirements, all
applicable electrical code(s) take precedence over the guidelines and procedures in the
present chapter, wherever applicable.
Wire size is calculated by first determining the appropriate maximum voltage drop requirement. Use the formula
below to calculate the circular mil area (CMA) wire size requirement. Determine the size and number of conduc-
tors required to satisfy the CMA requirement.
CMA = (A x LF x K) / AVD
A = Ultimate drain in amps.
LF = Conductor loop feet.
K = 11.1 constant factor for commercial (TW type) copper wire.
AVD = Allowable voltage drop.
Check again that the ampacity rating of the cable meets the requirement for the installation application. Consult
local electrical codes (NEC, CEC, etc.) for guidelines. If required, increase the size of the cable to meet the code.
Refer to Table C for cable size equivalents.
Table C — Cable size equivalents (AWG to Metric)
Cable size (see notes 1
and 2)
Circular mils Square millimeters Equivalent metric cable
20 AWG 1020 0.519 1
18 AWG 1624 0.8232 1
16 AWG 2583 1.309 1.5
14 AWG 4107 2.081 2.5
12 AWG 6530 3.309 4
10 AWG 10380 5.261 6
8 AWG 16510 8.368 10