Application and Constructure:
1: THHN: It indicates a single or stranded conductor having flame-retardant and heat-resistant thermoplastic insulation with a jacket of extruded nylon or equivalent material. The wire is rated 90oC dry only.
2: THWN: It indicates a single or stranded conductor having flame-retardant, moisture and heat resistant thermoplastic insulation with a jacket of extruded nylon or equivalent material. The wire is rated 75oC wet or dry
3: Conductor: Annealed solid or stranded copper wires
4: Insulation: Polyvinyl Chloride (PVC) Rated 105oC
5: Jacket: Nylon jacket is provided to protect PVC insulation against abrasions and scratches while pulling through conduits. It is also resistant to oil , gasoline and chemicals.
Specification:
Size  | NO. of Strands  | PVC Insulation Thickness  | Nylon Sheath Thickness  | Approx OD.  | Ampacity  | ||
AWG  | MCM  | mm  | mm  | mm  | THHN  | THWN  | |
14  | solid  | 0.38  | 0.1  | 2.6  | 15  | 15  | |
12  | solid  | 0.38  | 0.1  | 3.02  | 20  | 20  | |
10  | solid  | 0.51  | 0.1  | 3.81  | 30  | 30  | |
14  | 19  | 0.38  | 0.1  | 2.78  | 15  | 15  | |
12  | 19  | 0.38  | 0.1  | 3.27  | 20  | 20  | |
10  | 19  | 0.51  | 0.1  | 4.11  | 30  | 30  | |
8  | 19  | 0.76  | 0.13  | 5.43  | 50  | 65  | |
6  | 19  | 0.76  | 0.13  | 6.36  | 65  | 75  | |
4  | 19  | 1.02  | 0.15  | 8.11  | 85  | 95  | |
3  | 19  | 1.02  | 0.15  | 8.82  | 100  | 110  | |
2  | 19  | 1.02  | 0.15  | 9.63  | 115  | 130  | |
1  | 19  | 1.27  | 0.18  | 11.09  | 130  | 150  | |
1/0  | 19  | 1.27  | 0.18  | 12.08  | 150  | 170  | |
2/0  | 19  | 1.27  | 0.18  | 13.34  | 175  | 195  | |
3/0  | 19  | 1.27  | 0.18  | 14.64  | 200  | 225  | |
4/0  | 19  | 1.27  | 0.18  | 16.04  | 230  | 280  | |
250  | 37  | 1.52  | 0.2  | 17.79  | 255  | 290  | |
300  | 37  | 1.52  | 0.2  | 19.09  | 286  | 320  | |
350  | 37  | 1.52  | 0.2  | 20.39  | 310  | 350  | |
400  | 37  | 1.52  | 0.2  | 21.49  | 335  | 380  | |
500  | 37  | 1.52  | 0.2  | 23.59  | 380  | 430  | |