4 AWG XHHW-2 600V RD Single copper conductor, stranded and insulated with moisture, heat and flame resistant, chemically crosslinked polyethylene. Available in colors. Suitable for use in general purpose wiring applications and may be installed in raceway, conduit, direct burial and aerial installations where a cable having superior flame retardance is required. Suitable for use in 105°C dry systems. Also suitable for use in low leakage circuits requiring a dielectric constant of 3.5 or less (Hospital Grade).