New Boatbuilders Home Page - Electrical Table Wire Size Print Friendly Page
banner6a.jpg (17058 bytes) ELECTRICAL SYSTEMS

I am only going to very briefly cover the basics here. There is much, much more! Contact ABYC and the Coast Guard to get the latest standards for Electrical systems.

The following are not verbatim from the regulations. It is my own wording. Get a copy and read the regulation!

The following table is used to calculate the appropriate wire size based on the temperature of the insulation of the wire.

Note: This is the table that is in the Federal Regulations.  ABYC Standard E-11 has Five seperate tables based on how many conductors are in a wire bundle.

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Table 1 - ALLOWABLE AMPERAGE OF CONDUCTORS FOR SYSTEMS UNDER 50 VOLTS

Temperature Rating of Conductor Insulation

Conductor Size English (metric)

60 C (149 F)

75 C (167 F)

80 C (176 F)

90 C (194 F)

105 C (221 F)

125 C (257 F)

200 C (392 F)

Outside Engine space

Inside Engine Space

Outside Engine space

Inside Engine Space

Outside Engine space

Inside Engine Space

Outside Engine space

Inside Engine Space

Outside Engine space

Inside Engine Space

Outside Engine space

Inside Engine Space

Outside or Inside Engine Space

18 (0.8)

10

5.8

10

7.5

15

11.7

20

16.4

20

17.0

25

22.3

25

16 (1)

15

8.7

15

11.3

20

15.6

25

20.5

25

21.3

30

25.7

35

14 (2)

20

11.6

20

15.0

25

19.5

30

24.6

35

29.8

40

35.6

45

12 (3)

25

14.5

25

18.8

35

27.3

40

32.8

45

38.3

50

44.5

55

10 (5)

40

23.2

40

30.0

50

39.0

55

45.1

60

51.0

70

62.3

70

8 (8)

55

31.9

65

48.8

70

54.6

70

57.4

80

68.0

90

80.1

100

6 (13)

80

46.4

95

71.3

100

78.0

100

82.0

120

102

125

111

135

4 (19)

105

60.9

125

93.8

130

101

135

110

160

136

170

151

180

2 (32)

140

81.2

170

127

175

138

180

147

210

178

225

200

240

1 (40)

165

95.7

195

146

210

163

210

172

245

208

265

235

280

0 (50)

195

113

230

172

245

191

245

200

285

242

305

271

325

00 (62)

225

130

265

198

285

222

285

233

330

280

355

316

370

000 (81)

260

150

310

232

330

257

330

270

385

327

410

384

430

0000 (103)

300

174

380

270

385

300

385

315

445

378

475

422

510





Notes for the above table

Temperature Rating of Conductor Insulation
 

60oC (140oF)

75oC (167oF)

80oC (176oF)

90oC (194oF)

105oC (221oF)

 125oC (257oF) 200oC (392oF)
1. See the following table: Temperature Rating of conductor

0.58

 0.75 0.78 0.82 0.85 0.89 1.00
2. See the following Table: Number of current carrying conductors             Correction Factor
3             0.70
4 to 6             0.60
7 to 24             0.50
25 and above             0.40