Nonmetallic (NM-B) cable is commonly used in single family residential installations. From tables provided in this chapter, identify the ampacity of the following conductors:
a. NM-B cable with three No. 14 AWG copper conductors having THHN or THWN insulation
b. NM-B cable with three No. 12 AWG copper conductors having THHN or THWN insulation
c. NM-B cable with three No. 10 AWG copper conductors having THHN or THWN insulation

Transcribed Image Text:

Conductor Size (AWG or kcmil) Number of Ungrounded and Neutral Three Conductors Plus Grounding Conductor 14 NM-B Cable with Type THHN/THWN Copper Conductors Grounding (Bare) Conductor Size Nominal Size (mil) Approx. Net Weight per 1000 ft (lb) Ampacity 12086 2 14 360 X 162 58 15 2 2 2 2 2000 12 410 x 179 83 10 494 x 210 126 10 612 x 269 187 10 683 x 304 256 285 20 30 40 55 Four Conductors Plus Grounding Conductor 14 3 14 307 75 12 3 10 3 8 3 6 3 10 4 3 2000 12 347 109 20 10 422 167 10 565 254 650 357 55 8 892 593 PER 15 30 40 70 2 3 8 1034 856 95