Installation

Step 4: Selecting Load Wires

This section provides recommendations for selecting minimum load wire sizes.

Load Wiring

To select the wiring for connecting the load to the power supply, consider the following factors:

Insulation rating of the wire.

Current carrying capacity of the wire.

Maximum load wiring length for operation with remote sense lines.

Electrical noise and impedance effects of the load lines.

Insulation Rating

Use load wiring with a minimum insulation rating equivalent to the maximum output voltage of the power supply.

Current Carrying Capacity

The load wiring must have a current carrying capacity greater than the output rating of the power supply to ensure that the load wiring will not be damaged if the load is shorted. Table 2-2 shows the maximum current rating for various gauges of wire rated for 105 °C operation, based on a maximum current density of 450 A/cm2.

Operating at the maximum current rating shown in Table 2-2 results in an approximately 30 °C temperature rise for an appropriately-sized load wire operating in free air. Where load wiring must operate in areas with elevated ambient temperatures or bundles with other wiring, use larger gauges or wiring rated for higher temperatures.

Table 2-2Current Carrying Capacity for Load Wiring

Wire Size

Maximum Current

(AWG)

(Amps)

 

 

20

2.5

 

 

18

4

 

 

16

6

 

 

14

10

 

 

12

16

1021

836

Wire Size

Maximum Current

(AWG)

(Amps)

 

 

6

61

4

97

2

155

1

192

1/0

247

2/0

303

 

 

2-6

M370078-01

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Xantrex Technology XG 850 manual Selecting Load Wires, Load Wiring, Insulation Rating, Current Carrying Capacity