What is Article 300 in the NEC?
Article 300 contains the general requirements for all wiring methods included in the NEC. However, this Article does not apply to signal and communications systems as covered in Chapters 7 and 8. This Article is primarily concerned about how you install, route, splice, protect, and secure conductors and raceways.
What is the minimum amount of cable assembly including the sheath that must extend into a non metallic box when using nonmetallic sheathed cable?
1/4 inch
Nonmetallic-sheathed cable installations require that the cable assembly (sheath included) extend into the box a minimum of 1/4 inch through the cable knockout opening. This requirement refers only to nonmetallic boxes; installing the cable’s sheath 1/4 inch into metal boxes is allowed, but not required.
What is NEC Class 1/2 and 3 wiring?
Class 1 wiring is actually required to exceed standards for power and lighting wiring. It must sit in metal or non-metallic raceway or be metal-sheathed wiring as compared to jacketed cable such as type NM. Class 3 wiring is functionally similar to Class 2 wiring, but with higher voltage and power limitations.
What is class1 wire?
A class 1 circuit is the portion of the wiring system between the load side of the overcurrent protection device (OCPD) or the power-limited supply and the connected load. Class 1 circuits can be 600 volts or less, but 120 volts are more common and are usually preferred by OSHA inspectors for safety reasons.
What does the NEC state about unused openings in nonmetallic boxes?
Unused openings in boxes shall be effectively closed. When openings in non-metallic boxes are broken out and not used, the entire box must be replaced. NEC 110-12 and 370-18 Unused openings in boxes shall be effectively closed.
What is the minimum length of free wire needed in an electrical box?
At least 150 mm (6 in.) of free conductor, measured from the point in the box where it emerges from its raceway or cable sheath, shall be left at each outlet, junction, and switch point for splices or the connection of luminaires or devices.
What is the purpose of Article 344?
Rigid Metal Conduit (RMC). A threadable raceway of circular cross section designed for the physical protection and routing of conductors and cables and for use as an equipment grounding conductor when installed with its integral or associated coupling and appropriate fittings.