(a) Each conductor must be insulated, stranded copper.

(b) Except for intermittent surges each conductor must not carry a current greater than that specified in Table 5 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 of Table 5.

(d) Each conductor in a multiconductor sheath must be at least a No. 18 AWG conductor.

(e) Each conductor installed separately must be at least a No. 16 AWG conductor.

(f) Each No. 18 AWG conductor in a multiconductor sheath may not extend out of the sheath more than 30 inches.

(g) This section does not apply to communications systems; electronic navigation equipment; electronic circuits having a current flow of less than one ampere; conductors which are totally inside an equipment housing; resistance conductors that control circuit amperage; high voltage secondary conductors and terminations that are in ignition systems; pigtails of less than seven inches of exposed length and cranking motor conductors.

Table 5—Allowable Amperage of Conductors

Conductor size (AWG)Temperature rating of conductor insulation
60 °C (140 °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)
1810101520202525
1615152025253035
1420202530354045
1225253540455055
1040405055607070
8556570708090100
68095100100120125135
4105125130135160170180
3120145150155180195210
2140170175180210225240
1165195210210245265280
0195230245245285305325
00225265285285330355370
000260310330330385410430
0000300360385385445475510
NOTES
1. See the following table:60 °C75 °C80 °C90 °C105 °C125 °C200 °C
(140 °F)(167 °F)(176 °F)(194 °F)(221 °F)(257 °F)(392 °F)
Temperature rating of conductor0.580.750.780.820.850.891.00
2. See the following table:Correction
factor
Number of current carrying conductors:
30.70
4 to 6.60
7 to 24.50
25 and above.40
[CGD 73-217, 42 FR 5944, Jan. 31, 1977; 42 FR 24739, May 16, 1977, as amended by CGD 81-092, 48 FR 55736, Dec. 15, 1983]