64 APPENDIX
ancorproducts.com
Temperature Rating of Conductor Insulation The Law The Code of Federal Regulations (CFR) 183.425 Conductors (b) Except for intermittent surges each conductor must not carry a current greater than that specified for the conductor’s gauge and temperature rating. (c) For conductors in engine spaces, amperages must be corrected by the appropriate correction factor in Note 1. Due to engine heat, the ambient temperature in engine spaces is usually higher than in other spaces of the boat. Wiring in and passing through engine spaces must be able to operate at these higher ambient temperatures. The ampacity values are based on an ambient temperature of 86°F / 30°C which is considered reasonable for use on boats except in engine spaces. The correction factors in Note 1 converts the ampacities to acceptable values in an ambient temperature of 122°F / 50°C. This higher temperature has been selected as satisfactory for engine spaces. Note 1 is supplied to eliminate the need for calculating the corrections. The values are already corrected. 18–4/0 AWG Wire and Cable Specifications AWG SAE Ampacity Engine Space AWG mm 2 CM area CM area Outside Inside 18 0.8 1,600 1,537 20 17 16 1 2,600 2,336 25 21 14 2 4,100 3,702 35 30 12 3 6,500 5,833 45 38 10 5 10,500 9,343 60 51 8 8 16,800 14,810 80 68 6 13 26,600 24,538 120 102 4 21 42,000 37,360 160 136 2 34 66,500 62,450 210 178 1 42 83,690 77,790 245 208 1/0 53 105,600 98,980 285 242 2/0 68 133,100 125,100 330 280 3/0 85 167,800 158,600 385 327 4/0 107 211,600 205,500 445 378
Ampacity Inside of Engine Space (Note 1)
Ampacity Outside of Engine Space
Conductor Size AWG
18 16 14 12 10
20 25 35 45 60 80
17 21 30 38 51 68
8 6 4 3 2 1
120 160 180 210 245 285 330 385
102 136 153 178 208 242 280 327
1/0 2/0 3/0 4/0
445 378 *De-rating for engine space is 0.85 for 221°F / 105°C rated wire.
Powered by FlippingBook