La Marche A39DS, Installation And Operation Manual

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8
2.3 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 charger’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.
NOTE: It is recommended to use a battery disconnect breaker between charger and battery bank; helpful during
battery or charger maintenance.
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
Calculating Current Carrying Capacity of Wire
Table 5 – Wire Size/Area Table
NOTE: These are recommended sizes per La Marche Standards. The National Electrical Code (NEC) and Local
Wiring Codes must be followed.
DC Connection Procedure
To prevent the DC circuit breaker from tripping when connecting the battery, connections should be done in the
following order.
1. Make sure that the incoming voltage to the charger is turned off.
2. Turn off/open the charger’s AC and DC circuit breakers.
3. Connect the battery cables to the charger’s DC output terminals.
OBSERVE PROPER POLARITY .
4. Energize the charger by supplying AC voltage and turning on/closing the charger’s AC breaker. This will charge
the capacitors inside the charger.
5. After 30 seconds, turn on/close the DC breaker.
AVD
K LF A
CMA
´ ´
=
K LF
AVD CMA
MaxAmp
´
´
=
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