- Southwire® SIMpull® XHHW-2 aluminum conductors are primarily used in conduit or recognized raceways for service and feeder wiring as specified in the NEC. XHHW-2 conductors may be used in wet or dry locations at temperatures not to exceed 90 deg C. Voltage rating for XHHW-2 conductors is 600 V. Suitable for use in health care facilities per section 517.160 of the NEC where a dielectric constant of 3.5 or less may be specified. This product is designed to be installed without the application of pulling lubricant.