SynC · Topic
These are the standards in the SynC Standards library that cover Power Distribution. Each one is a complete, plain-language specification: the scope it applies to, the requirements that govern it, and a structured equipment datasheet listing the values a project has to decide — ratings, materials, setpoints, and the standards each is verified against. All of it is free to read without an account and published under CC BY-SA 4.0.
A standard usually carries several topics, so most of the entries below also appear under neighbouring subjects. The topics each one carries are listed on its own page.
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.
never for new adoptions — this standard has been split and superseded. For dry-type transformers rated 600 V and below use Low Voltage Dry Type Transformers; for transformers with a primary above 600 V (liquid-immersed pad-mounted and MV dry-type) use Medium Voltage Transformers.
never for new adoptions — this standard has been merged into Panelboards, which carries its full content under the simple name.
Dead-front, free-standing low voltage distribution switchboards rated 600V and below, built to UL 891 and NEMA PB 2, with group-mounted molded-case or insulated-case circuit breakers (fixed-mounted or individually drawout). Covers service entrance and downstream distribution boards for commercial, institutional, and industrial facilities.
A time-current coordination study for low- and medium-voltage power distribution systems rated 38 kV and below, where multiple overcurrent protective devices are installed in series and selective operation is required. Covers the analysis, settings recommendations, and deliverables that demonstrate the closest upstream protective device to a fault opens first, leaving the rest of the system energized. Includes coordination of relays, low-voltage power circuit breakers, molded-case and insulated-case breakers, fuses, and motor starter overload elements; coordination with transformer through-fault damage curves, conductor damage curves, and motor starting and inrush envelopes; and the dedicated selective-coordination requirements of NEC 700.27 and 701.27 for emergency and legally required standby systems.
Calculation of available three-phase and line-to-ground short-circuit currents at every bus, transformer secondary, switchboard, panelboard, motor control center, and significant motor connection in a low- or medium-voltage power distribution system. The study output is used to specify equipment interrupting ratings, withstand ratings, and bus bracing, and to verify that installed and proposed equipment complies with NFPA 70 Article 110.9 and 110.10.