Conduit Fill

Maximum Number of THHN/THWN Conductors in Conduit or Tubing per 1993 NEC

TFFN - Fixture Wires

Size (AWG) .5 inch .75 inch 1 inch 1.25 inch 1.5 inch 2 inch 2.5 inch 3 inch 3.5 inch 4 inch 5 inch 6 inch
18 19 34 55 97 132 216 0 0 0 0 0 0
16 15 26 43 76 104 169 0 0 0 0 0 0

THHN - THWN

Size (AWG) .5 inch .75 inch 1 inch 1.25 inch 1.5 inch 2 inch 2.5 inch 3 inch 3.5 inch 4 inch 5 inch 6 inch
14 13 24 39 69 94 154 0 0 0 0 0 0
12 10 18 29 51 70 114 164 0 0 0 0 0
10 6 11 18 32 44 73 104 160 0 0 0 0
8 3 5 9 16 22 36 51 79 106 136 0 0
6 1 4 6 11 15 26 37 57 76 98 154 0
4 1 2 4 7 9 16 22 35 47 60 94 137
3 1 1 3 6 8 13 19 29 39 51 80 116
2 1 1 3 5 7 11 16 25 33 43 67 97
1 0 1 1 3 5 8 12 18 25 32 50 72
1/0 0 1 1 3 4 7 10 15 21 27 42 61
2/0 0 1 1 2 3 6 8 13 17 22 35 51
3/0 0 1 1 1 3 5 7 11 14 18 29 42
4/0 0 1 1 1 2 4 6 9 12 15 24 35
250 0 0 1 1 1 3 4 7 10 12 20 28
300 0 0 1 1 1 3 4 6 8 11 17 24
350 0 0 1 1 1 2 3 5 7 9 15 21
400 0 0 0 1 1 1 3 5 6 8 13 19
500 0 0 0 1 1 1 2 4 5 7 11 16
600 0 0 0 1 1 1 1 3 4 5 9 13
750 0 0 0 0 1 1 1 2 3 4 7 11

*Unless otherwise specifically permitted elsewhere in this Code, the overcurrent protection for conductor types marked with an asterisk(*) shall not exceed 15 amperes for No. 14, 20 amperes for No. 12, and 30 amperes for No. 10 copper; or 15 amperes for 15 amperes for no. 12 and 25 ampers for No. 10 aluminum and copper-clad aluminum after any correction factors for ambient temperature and number of conductors have been applied. Table 310-16 NEC. 

This information presented within this section has been carefully prepared and is believed to be accurate. Alan Wire Company makes no warranties, expressed or implied, and disclaim any responsibility or liability for loss or damage as a result of the use of this information.

Combination of Conductors

For groups of combinations of conductors the conduit or tubing shall be such size that the sum of the cross sectional areas of the individual conductors will not be more than the percentage of the interior cross sectional area of the conduit or tubing shown in the following table:

Number of Conductors 1 2 3 4 Over 4
All conductor types except lead-covered (new or rewiring) 53 31 40 40 40
Lead-covered Conductors 55 30 40 38 3

*Unless otherwise specifically permitted elsewhere in this Code, the overcurrent protection for conductor types marked with an asterisk(*) shall not exceed 15 amperes for No. 14, 20 amperes for No. 12, and 30 amperes for No. 10 copper; or 15 amperes for 15 amperes for no. 12 and 25 ampers for No. 10 aluminum and copper-clad aluminum after any correction factors for ambient temperature and number of conductors have been applied. Table 310-16 NEC. 

This information presented within this section has been carefully prepared and is believed to be accurate. Alan Wire Company makes no warranties, expressed or implied, and disclaim any responsibility or liability for loss or damage as a result of the use of this information.