Indoor Use Only Voltage Rating = 600V Temp Rating = 90°C Solid Copper Conductors/Solid Copper Ground Type NM-B (Non-Metallic Sheathed Cable) is commonly used for residential wiring of luminaries, devices and appliances. Type NM-B ampacity limitation shall be in accordance with the 60ºC conductor temperature rating, as specified in the NEC. Type NM-B is rated 600-volt for both exposed and concealed work in normally dry locations. Type NM-B may be installed or fished in air voids and joints and in masonry block or tile walls where such walls are not exposed to, nor subject to, excessive moisture or dampness.