39
83503001 Rev G
3.9.2. Current Carrying Capacity
Two factors must be considered when selecting the wire size:
a) 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.
b) 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 for up to 5V in each load wire, it is
recommended to minimize the voltage drop (1V typical 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.
Maximum length in Feet to limit
voltage drop to 1V or less
Wire size
AWG
Resistivity
OHM/1000ft
10A
20A
50A
100A
200A
400A
14
2.526
40
20
8
4
2
---
12
1.589
60
30
12
6
3
---
10
0.9994
100
50
20
10
5
2
8
0.6285
160
80
32
15
8
4
6
0.3953
250
125
50
25
12
6
4
0.2486
400
200
80
40
20
10
2
0.1564
600
300
125
60
30
15
0
0.0983
1000
500
200
100
50
25
Table 3-2: Maximum wire length for 1V drop on lead (in feet)
Maximum length in meters to limit
voltage drop to 1V or less
Cross sect.
area
(mm²)
Resistivity
OHM/Km
10A
20A
50A
100A
200A
400A
2.5
8.21
12.0
6.0
2.4
1.2
0.6
0.3
4
5.09
18.6
9.8
4.0
2
1.0
0.5
6
3.39
29.4
14.8
5.8
2.9
1.45
0.7
10
1.95
51.2
25.6
10.2
5.1
2.5
1.25
16
1.24
80.0
40.0
16.0
8
4
2
25
0.795
125.0
62.0
25.2
12.6
6.3
3.1
35
0.565
177.0
88.0
35.4
17.7
8.8
4.4
Table 3-3: Maximum Wire Length for 1 V 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.
3.9.3. Wire Termination
The wires should be properly terminated with terminals securely attached. DO NOT use
unterminated wires for load connection at the power supply.
CAUTION
When local sensing, a short from +LS or +S to -V or -S or -LS, will cause damage to
the power supply. Reversing the sense wires might cause damage to the power
supply in local and remote sensing. (Do not connect -S to +V or +S to -V).
