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Wire Sizing Charts

Wire Sizing Charts

To find wire size required for less than 5% power loss

Read down the left-hand edge to the number showing solar amps or watts your wire will carry. Follow that line across to the right to find your wire length in feet from solar to batteries. At the top of the column above your wire length is the minimum wire size (gauge) to use. Smaller gauge equals larger wire. 

Buried DC cables must be copper, wet aluminum with DC corrodes quickly.

If your total solar power is over 25 amps, it is best to divide the solar into two smaller groups and run  separate pairs of cables to a 30 amp breaker for each group.

Copper Wire Size and Length Table, 5% loss for 12 VOLT Wiring
   

12ga

10ga

8ga

6ga

4ga

2ga

1/0

2/0

3/0

AMPS

WATTS

Distance in feet to run wire below, Wire size above 

 4

48

43

68

113

178

288

450

725

900

-

6

72

30

43

75

119

188

300

481

600

760

8

96

21

36

56

88

144

225

363

450

570

10

120

17

28

45

71

113

180

290

360

457

15

180

11

17

30

47

75

120

193

240

304

20

240

8

13

22

36

56

90

145

180

229

25

300

-

11

17

28

45

72

115

145

183

30

360

-

8

15

23

37

60

96

120

152

40

480

-

-

11

17

28

45

72

90

114

50

600

-

-

-

13

22

36

57

72

91

 

Copper Wire Size and Length Table, 5% loss for 24 VOLT Wiring
   

12ga

10ga

8ga

6ga

4ga

2ga

1/0

2/0

3/0

AMPS

WATTS

Distance in feet to run wire below, Wire size above 

4

96

87

137

226

356

576

900

-

-

-

6

144

60

87

150

238

376

600

962

-

-

8

192

42

72

112

177

288

450

726

900

-

10

240

35

57

90

142

226

360

580

720

914

15

360

22

35

60

95

150

240

386

480

608

20

480

17

27

45

72

112

180

290

360

458

25

600

-

22

35

57

90

145

230

290

366

30

720

-

17

30

47

75

120

192

240

304

40

960

-

-

23

35

57

90

145

180

228

50

1200

-

-

-

27

45

72

115

145

182

 

Copper Wire Size and Length Table, 5% loss for 48 VOLT Wiring
   

12ga

10ga

8ga

6ga

4ga

2ga

1/0

2/0

3/0

AMPS

WATTS

Distance in feet to run wire below, Wire size above 

4

192

174

274

452

712

1152

1800

-

-

-

6

288

120

174

300

476

752

1200

1924

-

-

8

384

84

144

224

354

576

900

1452

1800

-

10

480

70

114

180

284

452

720

1160

1440

1828

15

720

44

70

120

190

300

480

772

960

1216

20

960

34

54

90

144

224

360

580

720

916

25

1200

28

44

70

114

180

290

460

580

732

30

1440

24

34

60

94

150

240

384

480

608

40

1920

18

26

46

70

114

180

290

360

456

50

2400

-

22

28

54

90

144

230

290

364