10
2.4 Making the DC Output Connections
Before making any of DC output connections make sure you have read and fully understand the DC Connection
Procedure below.
Select proper size for the DC wiring from the wire size table on the previous page. If the
distance between the unit’s DC output and the DC load exceeds 10 feet, use the Power Cable Guide below to
minimize the voltage drop across the wire distance.
Power Cabling Guide
Use the following formulas and table to determine proper wire size for minimal voltage drop.
Table of Conventions
CMA = Cross section of wire in circular MIL area
A = Ultimate drain in amperes
LF = Conductor loop feet
MaxAmp = Maximum allowable amperes for given voltage drop
AVD = Allowable voltage drop
K = 11.1 for commercial (TW) copper wire (KS5482-01)
= 17.4 for aluminum (KS20189)
Calculating Wire Size Requirements
AVD
KLFA
CMA
Calculating Current Carrying Capacity of Wire
KLF
AVDCMA
MaxAmp
DC Connection Procedure
To prevent the DC circuit breaker from tripping when connecting the battery, connections should be done in the
following order.
1. Turn off the unit’s AC and DC circuit breakers.
2. Connect AC input line to the unit’s input terminals as described in Section 2.3.
3. Connect the battery cables to the unit’s DC output terminals.
OBSERVE PROPER POLARITY.
4. Energize the power supply by turning on the unit’s AC breaker. This will charge the capacitors inside the
unit and eliminate heavy arcing when the battery is connected.
5. After about 30 seconds, turn on the DC breaker
SIZE
(AWG)
AREA
CIR.MILS
SIZE
(MCM)
AREA
CIR.MILS
18 1620 250 250000
16 2580 300 300000
14 4110 350 350000
12 6530 400 400000
10 10380 500 500000
8 16510 600 600000
6 26240 700 700000
4 41740 750 750000
3 52620 800 800000
2 66360 900 900000
1 83690 1000 1000000
0 105600 1250 1250000
00 133100 1500 1500000
000 167800 1750 1750000
0000 211600 2000 2000000
able 7 - Wire Size/Area Table
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