Before selecting electrical cable, There are much more but here are just some criteria s to keep in mind :
Cable conductors
Cable AWG
Temperature
Shield type
Material type
No of pairs
Electrical wire size using table 310.16 NEC2008 on page 70-148. Simply calculate amperage (current) flow through the circuit and then apply the table.
SIZE AWG OR KCMIL
COPPER
COPPER
COPPER
ALUMINUM
ALUMINUM
ALUMINUM
SIZE AWG OR KCMIL
_
TYPE TW,UF
TYPES RHW ,THHW,THW, THWN,XHHW USE,ZW
RHW-2,THHN THHW,THW-2 (90°C)
TYPES TW,UF (60°C)
TYPES RHW THHW,THW THWN,XHHW USE
TYPES TBS,SA SIS,THHW
SIZE AWG OR KCMIL
18 16 14 12 10 8
_ _ 20 25 30 40
_ _ 20 25 35 50
14 18 25 30 40 55
_ _ _ 20 25 30
_ _ _ 20 30 40
_ _ _ 25 35 45
_ _ _ 12 10 8
6 4 3 2 1
55 70 85 95 110
65 85 100 115 130
75 95 110 130 150
40 55 65 75 85
50 65 75 90 100
60 75 85 100 115
6 4 3 2 1
1/0 2/0 3/0 4/0
125 145 165 195
150 175 200 230
170 195 225 260
100 115 130 150
120 135 155 180
135 150 175 205
1/0 2/0 3/0 4/0
250 300 350 400 500
215 240 260 280 320
255 285 310 335 380
290 320 350 380 430
170 190 210 225 260
205 230 250 270 310
230 225 280 305 350
250 300 350 400 500
600 700 750 800 900
335 385 400 410 435
420 460 475 490 520
475 520 535 555 585
285 310 320 330 335
340 375 385 395 425
385 420 435 450 480
600 700 750 800 900
1000 1250 1500 1750 2000
435 495 520 545 560
545 590 625 650 665
615 665 705 735 750
375 405 435 455 470
445 485 520 545 560
500 545 585 615 630
1000 1250 1500 1750 2000
Apply table to calculate electrical wire size Assume the current calculated result is 14A, cable type is copper THHN, insulated conductors rated at 90° C, and so based on the table, cable size is 18 AWG. For practical safety application, recommended power cable should be bigger than 12 AWG.
