AC Power

Standards

• Arc-Flash Study

  The arc-flash study for a project's electrical power distribution system: the incident energy and the arc-flash boundary at every bus a worker examines, adjusts, services, or maintains while it is energized, on AC systems from 208 V through 38 kV with utility, generator, inverter-based, and paralleled sources, and on the DC side of battery, energy storage, and photovoltaic equipment where the project includes it. Covers who performs the study and when it is issued, the IEEE 1584-2018 method and the methods applied outside its range, the buses studied, the source operating cases and the maintenance-mode cases, the arcing current variation, the clearing time taken from the accepted coordination settings, the arc-flash input data the system model does not already carry (electrode configuration, enclosure dimensions, bus gap, working distance), the content of the arc-flash label, the PPE arc rating the facility's safety program consumes, the mitigation recommendations, the report, and the five-year review and the events that call for a re-study.

• Conductors and Cables

  Building wire and cable for power, lighting, branch circuit, and feeder applications rated 600V and below in commercial, institutional, and industrial buildings. Covers single conductors installed in raceways and cable tray, Type MC metal-clad cable, and Type AC armored cable; conductor materials (copper and aluminum); insulation types (THHN/THWN-2, XHHW-2, RHW-2, USE-2); ampacity selection and derating; voltage drop; color coding and conductor identification; splicing, connectors, and terminations; pulling and installation; insulation resistance testing; and field acceptance.

• Low Voltage Panelboards (Superseded)

  never for new adoptions — this standard has been merged into Panelboards, which carries its full content under the simple name.

• Low Voltage Switchboards

  Dead-front, floor-standing distribution switchboards rated 1000 V and below, listed to UL 891 and built to NEMA PB 2, in which molded-case or insulated-case circuit breakers, fusible switches, or bolted-pressure switches are group-mounted or individually mounted on a common bus, whether installed as service equipment or downstream of a transformer, switchgear, or another switchboard. Covers the ratings, the interrupting rating basis, the main and feeder devices and their trip units, the bus, the structure and enclosure, arc-flash mitigation, the service entrance, surge protection, metering and communications provisions built into the assembly, identification, factory and field testing, installation, warranty, and spares, for three-phase and single-phase AC systems in indoor and outdoor locations.

• Short-Circuit Study

  The short-circuit study for a project's electrical power distribution system, from the utility point of delivery through every point at which an interrupting rating, a close-and-latch rating, a short-time withstand rating, a bus bracing rating, or a marked short-circuit current rating is confirmed, on AC systems rated 1000 V and below through 38 kV with utility, generator, inverter-based, and paralleled sources. Covers who performs the study and when it is delivered, the calculation method and the duty networks, the fault types and the maximum and minimum cases, the system model and the data it is built from (the utility's available fault current and X/R, transformer impedances, conductor impedances and lengths, motor and generator contribution, inverter-based sources, and the survey of existing equipment on a renovation), the source operating cases, the equipment duty evaluation, the treatment of series-rated combinations, the available fault current and date that NFPA 70 110.24 requires at the service equipment, the report and the model handed to the coordination and arc-flash studies, and the events that call for a re-study.

• Wiring Devices

  The receptacles, snap switches, wall-box dimmers, wall-box occupancy and vacancy sensors, and wall plates installed in outlet boxes on branch circuits rated 250 V and below and 60 A and below, in commercial, institutional, industrial, multifamily, and residential buildings. Covers device grade, the ampere rating and NEMA WD 6 configuration of receptacles, hospital-grade, isolated-ground, controlled, USB, surge-protective, locking, and special-purpose receptacles, the ground-fault and arc-fault devices installed at the outlet, tamper-resistant and weather-resistant devices and their covers, switch types and ratings, stand-alone dimmers and sensors with no connection to a control system, device color and plate material and finish, mounting height and orientation, terminations, device identification, field testing, warranty, and spares.

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