Editing American wire gauge

'''American wire gauge''' ('''AWG''') tells the diameter of an electrical conductor.  A 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==
Most of the following table came from [https://en.wikipedia.org/wiki/American_wire_gauge#Tables_of_AWG_wire_sizes Wikipedia].
Diameter and turns apply only to solid wire.  The total diameter of stranded wire is larger than solid, even though the conductive cross sections are the same.

{| 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;"
|+Allowable fill
!Conductors
!Percent filled
|-
| 1 || 53
|-
| 2 || 31
|-
| 3 or more || 40
|}


For type THHN wire, this works out to:

{| class="wikitable" style="textalign:center;"
|+Maximum THHN conductors entering box
!AWG !! {{frac|1|2}} 
! {{frac|3|4}} 
! 1 
! {{frac|1|1|4}} 
! {{frac|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;"
|+ Capacity of selected box sizes
!Box type !! Cubic inches !! 14 !! 12 !! 10 !! 8 !! 6
|-
! 4 x {{frac|1|1|4}}  Round !! 12.5 
| 6 || 5 || 5 || 4 || 0
|-
! 4 x {{frac|1|1|4}}  Square !! 18.0 
| 9 || 8 || 7 || 6 || 0
|-
! 4 x {{frac|1|1|2}}  Square !! | 21.0 
| 10 || 9 || 8 || 7 || 0
|-
! 4 x {{frac|2|1|8}} Square !! 30.3 
| 15 || 13 || 12 || 10 || 6
|-
! {{frac|4|11|16}} x {{frac|2|1|8}} Square !! 42.0 
| 21 || 18 || 16 || 14 || 6