Wiring Distance Chart

Wiring Distance (Measured in Feet)

6 Volt

12 Volt

12 Ga

10 Ga

8 Ga

6 Ga

Total Watts
on Wire Run

12 Ga

10 Ga

8 Ga

6 Ga

4 Ga

89

141

225

357

6

356

566

900

1431

2276

66

106

168

268

8

267

424

675

1073

1707

59

94

150

238

9

237

377

600

954

1517

53

84

135

214

10

213

339

540

859

1366

44

70

112

178

12

178

283

450

715

1138

33

53

84

134

16

133

212

337

536

853

29

47

75

119

18

118

188

300

477

758

22

35

56

89

24

89

141

225

357

569

21

33

54

85

25

85

135

216

343

546

19

31

50

79

27

79

125

200

318

505

17

28

45

71

30

71

113

180

286

455

14

23

37

59

36

59

94

150

238

379

12

20

32

51

42

51

80

128

204

325

11

18

30

47

45

47

75

120

190

303

11

17

28

44

48

44

70

112

178

284

10

16

27

42

50

42

67

108

171

273

7

11

18

28

75

28

45

72

114

182

5

8

13

21

100

21

33

54

85

136

5

9

14

150

14

22

36

57

91

6

10

200

10

16

27

42

68

5

8

250

8

13

21

34

54

7

300

7

11

18

28

45

Maximum Voltage Drop 5%

Key to Longer Wire Runs

The Wiring Distance Chart gives the maximum length of a given remote lamp
circuit, assume the entire remote load is concentrated at the end of the wire run.
If remote lamp fixtures are uniformly spaced along the circuit path (equal watts spaced at equal distance), the lengths in the table may be increased, based on the chart and formula below:

# OF FIXTURES

2

3

4

5

6

N

1.33

1.5

1.6

1.67

1.71

2N/(N+1)

MULTIPLY FEET BY

For example, a 100-foot long, 12-volt, remote lamp circuit has four 12-watt fixtures
spaced 25 feet apart. According to the Wire Distance Chart, #8 Ga. wire would be
required for 48 total watts up to 112 feet, to allow a 5% voltage drop or less.
However, since the fixtures are equal in wattage and are spaced equally along the
circuit, the distance of 70 feet for #10 Ga. wire can be multiplied by 1.6 (70 x 1.6 = 112), so in this case up to a 112-foot wire run with #10 Ga. wire would be acceptable.

Note: For systems operating at less than 50 volts, the smallest permissible wire size is #12 Ga. copper or equivalent per NFPA70 (National Electrical Code), Article 720-4.