Thhn/ Thwn-2/ Mtw Copper Building Wire and Cable

CONSTRUCTION :
THHN or THWN-2* or MTW copper conductors are annealed (soft) copper, insulated with a tough heat and moisture resistant polyvinyl chloride (PVC), over which a nylon (polyamide) or UL-listed equal jacket is applied Available in black, white, red, blue, green, yellow, brown, orange, and gray; Some colors standard, some subject to economic order quantity. 
Conductor sizes 2 AWG and larger listed and marked sunlight-resistant in black only

SPECIFICATION of MTW or THHN or THWN-2 type cable
Conductors shall be UL-listed Type MTW or THHN or THWN-2* gasoline and oil resistant II, suitable for operations at 600 volts as specified in the National Electrical Code. Sizes 14 through 1 AWG shall be rated VW-1, larger sizes shall be listed for CT use. Sizes 2 AWG and larger listed and marked sunlight-resistant in black only. Conductors shall be annealed copper, insulated with high-heat and moisture resistant PVC, jacketed with abrasion, moisture, gasoline, and oil resistant nylon or listed equivalent.

Application of thhn /thwn/tffn/mtw cable:
THHN or THWN-2* conductors are primarily used in conduit and cable trays for services, feeders, and branch circuits in commercial or industrial applications as specified in the National Electrical Code 2;

1) When used as Type THHN, conductor is suitable for use in dry locations at temperatures not to exceed 90° C;
2) When used as Type THWN-2*, conductor is suitable for use in wet or dry locations at temperatures not to exceed 90° C or not to exceed 75° C when exposed to oil or coolant;
3) When used as Type MTW, conductor is suitable for use in wet locations or when exposed to oil or coolant at temperatures not to exceed 60° C or dry locations at temperatures not to exceed 90° C (with ampacity limited to that for 75° C conductor temperature per NFPA 79)
Conductor temperatures not to exceed 105° C in dry locations when rated AWM and used as appliance wiring material. Voltage for all applications is 600 volts

STANDARDS & REFERENCE:
THHN or THWN-2* or MTW (also AWM) meets or exceeds all applicable ASTM specifications, UL Standard 83, UL Standard 1063 (MTW), Federal Specification A-A-59544, and requirements of the National Electrical Code.
AWM Conductors shall be UL-listed Type THHN or THWN-2* or MTW or AWM, suitable for
Operation at 600 volts at conductor temperatures not to exceed 105° C.