Editing American wire gauge

'''American wire gauge''' ('''AWG''') tells the diameter of an electrical conductor.  The conductor's current capacity depends upon the resistance per unit length and the temperature rating of the insulation.  Wire type THHN is rated at 90&nbsp;°C, and it has an added nylon jacket.

Electric welders use a lot of current for short periods.  The National Electrical Code (NEC) provides for welders by allowing wire size of only half the capacity that would otherwise be required.  For example, a 50 amp circuit breaker, a 50 amp outlet, but only 10 AWG wire.

A similar exception is made for protective ground wires, which can have only half the capacity of the current carrying conductors.

==Tables of AWG wire sizes simplified from [https://en.wikipedia.org/wiki/American_wire_gauge#Tables_of_AWG_wire_sizes Wikipedia]==
Parts of the following following table apply only to solid wire.  The diameter of stranded wire is larger than indicated.

{| class="wikitable" style="textalign:center;"
! rowspan=4 | AWG
! rowspan=3 colspan=2 | Diameter <br/> (of solid wire)
! rowspan=3 colspan=2 | Turns of wire, <br />without insulation <br/> (of solid wire)
! rowspan=3 colspan=2 | Area
! colspan=8 | Copper wire
|-
! rowspan=2 colspan=2 | Resistance/length
! colspan=3 | Ampacity
|-
! 60&nbsp;°C
! 75&nbsp;°C
! 90&nbsp;°C
|-
! (in)
! (mm)
! (per&nbsp;in)
! (per&nbsp;cm)
! (kcmil)
! (mm<sup>2</sup>)
! (mΩ/m
! (mΩ/ft
! colspan=3 | (A)
|-
| 0000 (4/0) || 0.4600
                       || 11.684
|                                   2.17 || 0.856 || 212 || 107   || 0.1608 || 0.04901|| 195 || 230 || 260 
|-
|  000 (3/0) || 0.4096 || 10.405 || 2.44 || 0.961 || 168 || 85.0  || 0.2028 || 0.06180|| 165 || 200 || 225 
|-
|   00 (2/0) || 0.3648 ||  9.266 || 2.74 || 1.08 || 133  || 67.4  || 0.2557 || 0.07793|| 145 || 175 || 195 
|-
|    0 (1/0) || 0.3249 ||  8.251 || 3.08 || 1.21 || 106  || 53.5  || 0.3224 || 0.09827|| 125 || 150 || 170 
|-
|    1       || 0.2893 ||  7.348 || 3.46 || 1.36 || 83.7 || 42.4  || 0.4066 || 0.1239 || 110 || 130 || 145 
|-
|    2       || 0.2576 ||  6.544 || 3.88 || 1.53 || 66.4 || 33.6  || 0.5127 || 0.1563 ||  95 || 115 || 130
|-
|    3       || 0.2294 ||  5.827 || 4.36 || 1.72 || 52.6 || 26.7  || 0.6465 || 0.1970 ||  85 || 100 || 115 
|-
|    4       || 0.2043 ||  5.189 || 4.89 || 1.93 || 41.7 || 21.2  || 0.8152 || 0.2485 ||  70 ||  85 ||  95
|-
|    5       || 0.1819 ||  4.621 || 5.50 || 2.16 || 33.1 || 16.8  || 1.028  || 0.3133 ||colspan=3|        
|-
|    6       || 0.1620 ||  4.115 || 6.17 || 2.43 || 26.3 || 13.3  || 1.296  || 0.3951 ||  55 ||  65 ||  75 
|-
|    7       || 0.1443 ||  3.665 || 6.93 || 2.73 || 20.8 || 10.5  || 1.634  || 0.4982 ||colspan=3|         
|-
|    8       || 0.1285 ||  3.264 || 7.78 || 3.06 || 16.5 || 8.37  || 2.061  || 0.6282 ||  40 ||  50 ||  55 
|-
|    9       || 0.1144 ||  2.906 || 8.74 || 3.44 || 13.1 || 6.63  || 2.599  || 0.7921 ||colspan=3|        
|-
|   10       || 0.1019 ||  2.588 || 9.81 || 3.86 || 10.4 || 5.26  || 3.277  || 0.9989 ||  30 ||  35 ||  40  
|-
|   11       || 0.0907 ||  2.305 || 11.0 || 4.34 || 8.23 || 4.17  || 4.132  || 1.260  ||colspan=3|         
|-
|   12       || 0.0808 ||  2.053 || 12.4 || 4.87 || 6.53 || 3.31  || 5.211  || 1.588  ||  20 ||  25 ||  30  
|-
|   13       || 0.0720 ||  1.828 || 13.9 || 5.47 || 5.18 || 2.62  || 6.571  || 2.003  ||colspan=3|        
|-
|   14       || 0.0641 ||  1.628 || 15.6 || 6.14 || 4.11 || 2.08  || 8.286  || 2.525  ||  15 ||  20 ||  25 
|-
|   15       || 0.0571 ||  1.450 || 17.5 || 6.90 || 3.26 || 1.65  || 10.45  || 3.184  ||colspan=3|          
|-
|   16       || 0.0508 ||  1.291 || 19.7 || 7.75 || 2.58 || 1.31  || 13.17  || 4.016  || 22*free air || 13*enclosed ||  18  
|-
|   17       || 0.0453 ||  1.150 || 22.1 || 8.70 || 2.05 || 1.04  || 16.61  || 5.064  ||colspan=3|          
|-
|   18       || 0.0403 ||  1.024 || 24.8 || 9.77 || 1.62 || 0.823 || 20.95  || 6.385  || 10 ||   14 ||  16  
|-
|   19       || 0.0359 ||  0.912 || 27.9 || 11.0 || 1.29 || 0.653 || 26.42  || 8.051  ||  — ||  — || —     
|-
|   20       || 0.0320 ||  0.812 || 31.3 || 12.3 || 1.02 || 0.518 || 33.31  || 10.15  || 7.5 ||  11 || —    
|-
|   21       || 0.0285 ||  0.723 || 35.1 || 13.8 || 0.810 || 0.410 || 42.00 || 12.80  ||  — ||  — || —      
|-
|   22       || 0.0253 ||  0.644 || 39.5 || 15.5 || 0.642 || 0.326 || 52.96 || 16.14  ||  7 ||  5 || —      
|-
|   23       || 0.0226 ||  0.573 || 44.3 || 17.4 || 0.509 || 0.258 || 66.79 || 20.36  ||  —   ||  — || —   
|-
|   24       || 0.0201 ||  0.511 || 49.7 || 19.6 || 0.404 || 0.205 || 84.22 || 25.67  ||  3.5 ||  2.1 || — 
|-
|   25       || 0.0179 ||  0.455 || 55.9 || 22.0 || 0.320 || 0.162 || 106.2 || 32.37  ||  —   ||  — || —   
|-
|   26       || 0.0159 ||  0.405 || 62.7 || 24.7 || 0.254 || 0.129 || 133.9 || 40.81  ||  2.2 ||  1.3 || — 
|-
|   27       || 0.0142 ||  0.361 || 70.4 || 27.7 || 0.202 || 0.102 || 168.9 || 51.47  ||  —   ||  — || —   
|-
|   28       || 0.0126 ||  0.321 || 79.1 || 31.1 || 0.160 || 0.0810 || 212.9 || 64.90 ||  1.4 ||  0.85 || — 
|-
|   29       || 0.0113 ||  0.286 || 88.8 || 35.0 || 0.127 || 0.0642 || 268.5 || 81.84 ||  —   ||  — || —   
|-
|   30       || 0.0100 ||  0.255 || 99.7 || 39.3 || 0.101 || 0.0509 || 338.6 || 103.2 ||  0.86 || 0.52 || —  
|-
|   31       || 0.00893 || 0.227 || 112  || 44.1 || 0.0797 || 0.0404 || 426.9 || 130.1 ||  —  ||  — || —    
|-
|   32       || 0.00795 || 0.202 || 126  || 49.5 || 0.0632 || 0.0320 || 538.3 || 164.1 || 0.53 ||  0.3 || — 
|-
|   33       || 0.00708 || 0.180 || 141  || 55.6 || 0.0501 || 0.0254 || 678.8 || 206.9 ||  —  ||  — || —   
|-
|   34       || 0.00630 || 0.160 || 159  || 62.4 || 0.0398 || 0.0201 || 856.0 || 260.9 || 0.3 || 0.180 || — 
|-
|   35       || 0.00561 || 0.143 || 178  || 70.1 || 0.0315 || 0.0160 || 1079  || 329.0 ||  —  ||  — || —   
|-
|   36       || 0.00500 || 0.127
|                                   200
|                                           78.7 || 0.0250 || 0.0127 || 1361  || 414.8 ||  — ||  — || —     
|-
|   37       || 0.00445 || 0.113 || 225  || 88.4 || 0.0198 || 0.0100 || 1716  || 523.1 ||  — ||  — || —     
|-
|   38       || 0.00397 || 0.101 || 252  || 99.3 || 0.0157 || 0.00797 || 2164 || 659.6 ||  — ||  — || —     
|-
|   39       || 0.00353 || 0.0897 || 283 || 111  || 0.0125 || 0.00632 || 2729 || 831.8 ||  — ||  — || —     
|-
|   40       || 0.00314 || 0.0799 || 318 || 125  || 0.00989 || 0.00501 || 3441 || 1049 ||  — ||  — || —    
|}

==Number of conductors in conduit==
National Electrical Code Article 348-6 limits the total cross sectional area of conductors to a certain percentage of the  cross sectional area of a conduit.

{| class="wikitable" style="textalign:center;"
!Conductors
!Percent filled
|-
| 1 || 53
|-
| 2 || 31
|-
| 3 or more || 40
|}

For type THHN wire, this works out to:

{| class="wikitable" style="textalign:center;"
!AWG !! 1/2 !! 3/4 !! 1 !! 1 1/4 !! 1 1/2
|-
! 14 
| 13 || 24 || 39 || 69 || 94 
|-
! 12 
| 10 || 18 || 29 || 51 || 70 
|-
! 10 
| 6 || 11 || 18 || 32 || 44 
|-
! 8 
| 3 || 5 || 9 || 16 || 22 
|-
! 6 
| 1 || 4 || 6 || 11 || 15 
|-
! 4 
| 1 || 2 || 4 || 7 || 9 
|}

==Number of conductors in a box==
Article 370-6 limits the number of conductors entering a box.  A conductor that passes through a box, without any connection, counts as one conductor.  A conductor that begins and ends within a box is not counted at all.  The size of devices, such as outlets and switches, must be subtracted from the capacity of the box.

{| class="wikitable" style="textalign:center;"
!Box type !! Cubic inches !! 14 !! 12 !! 10 !! 8 !! 6
|-
! 4 x 1 1/4 Square !! | 18.0 
| 9 || 8 || 7 || 6 || 0
|-
! 4 x 1 1/2 Square !! | 21.0 
| 10 || 9 || 8 || 7 || 0
|-
! 4 x 2 1/8 Square !! | 30.3 
| 15 || 13 || 12 || 10 || 6