Power Supply User Manual
8
3.7 CONNECTING THE LOAD
wire size
Resistivity Maximum length in Feet to limit voltage
AWG Ohm/kft drop to 1V or less.
5A 10A 20A 50A 150A
14 2.526 80 40 20 8 2
12 1.589 120 60 30 12 3.4
10 0.9994 200 100 50 20 6
8 0.6285 320 160 80 32 10
6 0.3953 500 250 125 50 16
4 0.2486 800 400 200 80 26
2 0.1564 1200 600 300 125 40
0 0.0983 2000 1000 500 200 68
Table 3-2:Maximum wire length for 1V drop on lead (in feet).
Cross sect. Resistivity
Maximum length in meters to limit voltage
Area
Ohm/km drop to 1V or less.
(mm^2) 5A 10A 20A 50A 150A
2.5 8.21 24.0 12.0 6.0 2.4 0.8
4 5.09 39.2 18.6 9.8 4.0 1.4
6 3.39 59.0 29.4 14.8 5.8 2.0
10 1.95 102.6 51.2 25.6 10.2 3.4
16 1.24 160.0 80.0 40.0 16.0 5.4
25 0.795 250.0 125.0 62.0 25.2 8.4
35 0.565 354.0 177.0 88.0 35.4 11.8
Table 3-3:Maximum wire length for 1V drop on lead (in meters).
For currents not shown in Tables 3-2 and 3-3 , use the formula :
Maximum length=1000/(current*resistivity)
Where current is expressed in ampers and resistivity in ohms/km or ohms/1000ft.
3.7.1 Load Wiring.
The following considerations should be made to select wiring for connecting the load to the power supply:
* Current carrying capacity of the wire (refer to 3.7.2).
*Insulation rating of the wire should be at least equivalent to the maximum output voltage of the power
supply.
*Maximum wire length and voltage drop (refer to 3.7.2).
*Noise and impedance effects of the load wiring (refer to 3.7.3).
3.7.2 Current Carrying Capacity
Two factors should must be considered while selecting the wire size. 1.Wires should be at least heavy
enough not to overheating 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.
Please refer to Tables 3-2 and 3-3 for maximum wire length to limit the voltage drop in American and
European dimensions respectively.
WARNING
Turn off the AC input power before making or changing any rear panel
connection. Ensure that all connections are securely tightened before
applying power. There is a potential shock hazard when using a power
supply with a rated output greater than 40V.