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Wire insulation chart

Trade Name Letter Max. Temp. Application Provisions
FLOURINATED ETHYLENE PROPYLENEFEP OR FEPB90¡C 194¡F 200¡C 392¡FDRY AND DAMP LOCATIONS DRY LOCATIONS - SPECIAL APPLICATIONS (2)
MINERAL INSULATION (METAL SHEATHED)MI90¡C 194¡F 250¡C 482¡FDRY AND WET LOCATIONS SPECIAL APPLICATIONS (2)
MOISTURE, HEAT AND OIL RESISTANT THERMOPLASTICMTW **60¡C 140¡F 90¡C 194¡FMACHINE TOOL WIRING IN WET LOCATIONS, NFPA#79-ART. 670 MACHINE TOOL WIRING IN DRY LOCATIONS, NFPA#79-ART. 670
PAPER 85¡C 185¡FFOR UNDERGROUND SERVICE CONDUCTORS, OR BY SPECIAL PERMISSION
PERFLUOROALKOXYPFA90¡C 194¡F 200¡C 392¡FDRY AND DAMP LOCATIONS DRY LOCATIONS - SPECIAL APPLICATIONS (2)
PERFLUOROALKOXYPFAH250¡C 482¡FDRY LOCATIONS ONLY. ONLY FOR LEADS WITHIN APPARATUS OR WITHIN RACEWAYS CONNECTED TO APPARATUS, (NICKEL OR NICKEL COATED COPPER ONLY).
THERMOSET THERMOSETRH RHH75¡C 167¡F 90¡C 194¡FDRY AND DAMP LOCATIONS DRY AND DAMP LOCATIONS
MOISTURE-RESISTANT THERMOSET MOISTURE-RESISTANT THERMOSETRHW(5) RHW-275¡C 167¡F 90¡C 194¡FDRY AND WET LOCATIONS - OVER 2,000 VOLT INSULATION SHALL BE OZONE-RESISTANT DRY AND WET LOCATIONS
SILICONESA90¡C 194¡F 125¡C 257¡FDRY AND DAMP LOCATIONS FOR SPECIAL APPLICATIONS (2)
THERMOSETSIS90¡C 194¡FSWITCHBOARD WIRING ONLY
THERMOPLASTIC AND ASBESTOSTA90¡C 194¡FSWITCHBOARD WIRING ONLY
THERMOPLASTIC AND FIBROUS OUTER BRAIDTBS90¡C 194¡FSWITCHBOARD WIRING ONLY
EXTENDED POLYTETRAFLUOROETHYLENETFE250¡C 482¡FDRY LOCATIONS ONLY. ONLY FOR LEADS WITHIN APPARATUS OR WITHIN RACEWAYS CONNECTED TO APPARATUS, (OR AS OPEN WIRING) (NICKEL OR NICKEL COATED COPPER ONLY).
HEAT-RESISTANT THERMOPLASTICTHHN90¡C 194¡FDRY AND DAMP LOCATIONS
MOISTURE AND HEAT-RESISTANT THERMOPLASTICTHHW75¡C 167¡F 90¡C 194¡FWET LOCATION DRY LOCATION
MOISTURE AND HEAT-RESISTANT THERMOPLASTICTHW (5)75¡C 167¡F 90¡C 194¡FDRY & WET LOCATIONS SPECIAL APPL. WITHIN ELECTRIC DISCHARGE LIGHTING EQUIPMENT LIMITED TO 1000 OPEN-CIRCUIT VOLTS OR LESS, (SIZE 14-8 ONLY AS PERMITTED IN SECTION 410-31).
MOISTURE AND HEAT-RESISTANT THERMOPLASTICTHWN (5)75¡C 167¡FDRY AND WET LOCATIONS
MOISTURE RESISTANT THERMOPLASTICTW60¡C 140¡FDRY AND WET LOCATIONS
UNDERGROUND FEEDER AND BRANCH-CIRCUIT CABLE-SINGLE CONDUCTOR, (FOR TYPE "UF" CABLE EMPLOYING MORE THAN 1 CONDUCTOR. (SEE NEC ART. 339)UF60¡C 140¡F 75¡C 167¡F (8)SEE ARTICLE 339 N.E.C.
UNDERGROUND SERVICE ENTRANCE CABLE SINGLE CONDUCTOR, (FOR TYPE "USE" CABLE EMPLOYING MORE THAN 1 CONDUCTOR. SEE N.E.C. ART. 338)USE (5)75¡C 167¡FSEE ARTICLE 338 N.E.C.
THERMOSETXHH90¡C 194¡FDRY AND DAMP LOCATIONS
MOISTURE-RESISTANT THERMOSETXHHW (5)90¡C 194¡F 75¡C 167¡FDRY AND DAMP LOCATIONS WET LOCATIONS
MOISTURE-RESISTANT THERMOSETXHHW-290¡C 194¡FDRY AND WET LOCATIONS
MODIFIED ETHYLENE TETRAFLUOROETHYLENEZ90¡C 194¡F 150¡C 302¡FDRY AND DAMP LOCATIONS DRY LOCATIONS SPECIAL APPLICATIONS (2)
MODIFIED ETHYLENE TETRAFLUOROETHYLENEZW (5)75¡C 167¡F 90¡C 194¡F 150¡C 302¡FWET LOCATIONS DRY AND DAMP LOCATIONS DRY LOCATIONS - SPECIAL APPLICATIONS (2)

  1. Some insulations do not require an outer covering.
  2. Where design conditions require maximum conductor operating temperatures above 90oC (194oF).
  3. For signaling circuits permitting 300-volt insulation.
  4. For size Nos. 14-12, RHH insulation shall be 45 mils thickness.
  5. Listed wire types designeated with the suffix "-2," such as RHW-2, shall be permitted to be used at a continuous 90oC (194oF) operating temperature, wet or dry.
  6. Some rubbver insulations do not require an outer covering.
  7. Includes integral jacket.
  8. For ampacity limiation, see Section 339-5 NEC.
  9. Insulation thickness shall be permitted to be 80 mils for listed Type USE conductors that have been subjected to special investigations. The non-metallic covering over individual rubber-covered conductors of aluminum-sheathed cable and of lead-sheathed or multiconductor cable shall not be required to be flame retardant. For Type MC cable, see Section 334-20. For nonmetallic-sheathed cable, see Section 336-30. For Type UF cable, see Section 339-1.

Reprinted with permission from NFPA 70-1999, the National Electrical Code®, Copyright 1998, National Fire Protection Association, Quincy, MA 02269. This reprinted material is not the referenced subject which is represented only by the Standard in its entirety.
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Insulation
 
 
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