Instructions

42
Wire size
AWG
Resistivity
Ohm/1000ft
Maximum length in feet to limit
voltage drop to 1V or less
5A 10A 20A 50A 80A
14 2.526 80 40 20 8 5
12 1.589 120 60 30 12 7.5
10 0.9994 200 100 50 20 12.5
8 0.6285 320 160 80 32 20
6 0.3953 500 250 125 50 31
4 0.2486 800 400 200 80 50
2 0.1564 1200 600 300 125 78
Table 3-2: Maximum wire length for 1V drop on lead (in feet)
Cross sect.
area
(mm
2
)
Resistivity
Ohm/Km
Maximum length in meters to limit
voltage drop to 1V or less
5A 10A 20A 50A 80A
2.5 8.21 24.0 12 6 2.4 1.5
4 5.09 39.2 18.6 9.8 4 2.5
6 3.39 59.0 29.4 14.8 5.8 3.6
10 1.95 102.6 51.2 25.6 10.2 6.3
16 1.24 160.0 80 40 16 10
25 0.795 250.0 125 62 25.2 15.7
35 0.565 354.0 177 88 35.4 22
Table 3-3: Maximum wire length for 1V drop on lead (in meters)
For currents not shown in Table 3-2 and 3-3, use the formula:
Maximum length=1000/(current x resistivity)
Where current is expressed in amperes and resistivity in ohms/km or ohms/1000ft.
3.9.2 Current Carrying Capacity
Two factors must be considered when selecting the wire size:
1. Wires should be at least heavy enough not to overheat while carrying the power supply load
current at the rated load, or the current that would flow in the event the load wires were
shorted, whichever is greater.
2. Wire size should be selected to enable voltage drop per lead to be less than 1.0V at the rated
current. Although units will compensate higher voltage drop in each load wire (refer to the
specifications). It is recommended to minimize the voltage drop (1V maximum) to prevent
excessive output power consumption from the power supply and poor dynamic response
to load changes. Please refer to Tables 3-2 and 3-3 for maximum wire length to limit voltage
drop in American and European dimensions respectively.