We often see 6 3 romex wire , 10 2 romex wire,12 2 250 ft romex,6 3 nm b,romex 10 3,12 2 with ground romex,nm b 8 3,4 3 nm b wire these letters in wires and cables, so what do they mean? Actually, these are some models of American standard nm b wires.
The meaning of nm is non-metallic, and B means building wire
NM-B wire is an American standard flat cable specifically designed for use in mobile rooms as a socket and switch. This cable not only complies with AWG specifications, but also requires UL719 certification for nm b wire to ensure its safety and reliability. The use of NM-B wires, especially in residential buildings, can effectively meet the needs of electrical wiring and ensure the normal use and safety of household appliances. In addition, NM-B wires also have fire-resistant materials that can provide certain protection in emergency situations such as fires, increasing residential safety
We often see models of NB wires with romex inside, which is a trademark of South Wire in the United States. The letters 10 or 12 in front of each specification indicate the product's specifications, such as 10awg or 12awg, while ground represents a bare copper wire inside the NB wire as the grounding wire
The core wire of the nm b wire is a nylon sheathed wire THHN wire or THWN 2 wire, with PVC insulation and a transparent nylon coated insulation outer layer The core wires are arranged in parallel or twisted into a circle In general, a 2-core grounded nm b wire is a flat wire, such as a 12 2 nm cable, 8 2 romex wire, nm b10 2 with ground romex. A 3-core grounded nm b cable is a round wire, such as a 6 3 nm b wire, 10 3 nm b, 6 3 w ground romex
The sheath material is a special heat-resistant thermoplastic sheath made of highly flame-retardant PVC material, which is wear-resistant, high temperature resistant, low temperature resistant, and resistant to rolling. It is particularly suitable for use as a building wire. Working voltage: 600 V, operating temperature range: 90 ° C in a dry environment. The nmb wire complies with UL (MTW) machine tool wire CSA and other US and Canadian standards, enabling nmb to be used simultaneously in the North American market.
