Chapter 3

Outdoor Overhead Conductors over 1000 Volts Scope. This article covers the use and installation for outdoor overhead conductors over 1000 volts, nominal. ARTICLE 399 — OUTDOOR OVERHEAD CONDUCTORS OVER 1000 VOLTS 399.2 Definition. Outdoor Overhead Conductors. Single conductors, insulated, covered, or bare, installed outdoors on support structures in free air. 399.10 Uses Permitted. Outdoor overhead conductors over 1000… read more »

Open Wiring on Insulators Part I. General Scope. This article covers the use, installation, and construction specifications of open wiring on insulators. Definition. Open Wiring on Insulators. An exposed wiring method using cleats, knobs, tubes, and flexible tubing for the protection and support of single insulated conductors run in or on buildings. Part II. Installation 398.10 Uses… read more »

Messenger-Supported Wiring Part I. General Scope. This article covers the use, installation, and construction specifications for messenger-supported wiring. Definitions. N Insulated Conductor. For the purposes of this article, an insu‐ lated conductor includes the following: Conductor types described in 310.104, and Overhead service conductors encased in a polymeric material that has been evaluated for the applied nominal… read more »

Concealed Knob-and-Tube Wiring Part I. General Scope. This article covers the use, installation, and construction specifications of concealed knob-and-tube wiring. Definition. Concealed Knob-and-Tube Wiring. A wiring method using knobs, tubes, and flexible nonmetallic tubing for the protec‐ tion and support of single insulated conductors. Part II. Installation 394.10 Uses Permitted. Concealed knob-and-tube wiring shall be permitted to be… read more »

Low-Voltage Suspended Ceiling Power Distribution Systems Part I. General Scope. This article covers the installation of low-voltage suspended ceiling power distribution systems. Definitions. Busbar. A noninsulated conductor electrically connected to the source of supply and physically supported on an insulator providing a power rail for connection to utilization equipment, such as sensors, actuators, A/V devices, low-voltage luminaire… read more »

Cable TraysPart I. General Scope. This article covers cable tray systems, including ladder, ventilated trough, ventilated channel, solid bottom, and other similar structures.Informational Note: For further information on cable trays, see ANSI/NEMA–VE 1-2009, Metal Cable Tray Systems; NECA/NEMA 105-2015, Standard for Installing Metal Cable Tray Systems; and NEMA–FG 1-1993, Nonmetallic Cable Tray Systems. Definition. Cable Tray System. A unit or… read more »

Underfloor Raceways Scope. This article covers the use and installation requirements for underfloor raceways. Definition.Underfloor Raceway. A raceway and associated components designed and intended for installation beneath or flush with the surface of a floor for the installation of cables and electrical conductors. Use. Permitted. The installation of underfloor raceways shall be permitted beneath the surface of concrete… read more »

Surface Metal Raceways Table 384.22 Channel Size and Inside Cross-Sectional Area methods at intervals not to exceed 3 m (10 ft) and within 900 mm (3 ft) of channel raceway terminations and ends. 384.56 Splices and Taps. Splices and taps shall be permitted in raceways that are accessible after installation by having a removable cover. The… read more »

Surface Metal Raceways Table 384.22 Channel Size and Inside Cross-Sectional Area methods at intervals not to exceed 3 m (10 ft) and within 900 mm (3 ft) of channel raceway terminations and ends. 384.56 Splices and Taps. Splices and taps shall be permitted in raceways that are accessible after installation by having a removable cover. The… read more »

Strut-Type Channel Raceway Part I. General Scope. This article covers the use, installation, and construction specifications of strut-type channel raceway. Definition. Strut-Type Channel Raceway. A metal raceway that is intended to be mounted to the surface of or suspended from a structure, with associated accessories for the installation of electrical conductors and cables. 384.6 Listing Requirements. Strut-type channel raceways and accessories shall… read more »