SynC · Topic
These are the standards in the SynC Standards library that cover Medium Voltage. 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.
Engineering analysis to calculate incident energy and the arc-flash boundary at every piece of electrical equipment where workers may interact with the equipment while it is energized or while it could be placed into an electrically safe work condition. Applies to AC systems from 208V through medium voltage, in commercial, institutional, industrial, and healthcare facilities. The study produces equipment labels, PPE specifications, and the documentation that supports an NFPA 70E-compliant electrical safety program.
never for new adoptions — this standard has been split and superseded.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.
Identification labels, nameplates, warning signs, panel directories, and color-coding for electrical distribution equipment and wiring rated 600V and below and for medium-voltage equipment served by the same project — switchgear, switchboards, panelboards, transformers, motor control centers, disconnects, automatic transfer switches, junction boxes, raceways, and conductors. Covers arc-flash warning labels driven by the arc-flash study, voltage-class and system color coding (normal, emergency, critical, standby, fire alarm, security), panelboard circuit directories, disconnecting-means identification, available fault current marking, and conductor and conduit identification.
Metal-clad medium-voltage switchgear rated above 1 kV through 38 kV using drawout vacuum or SF6 circuit breakers, built to IEEE C37.20.2 and the ANSI/IEEE C37.04 / C37.06 / C37.09 series, for utility-customer substations, large commercial campuses, healthcare and higher-education central plants, data centers, and industrial facilities. Covers 5 kV, 15 kV, 27 kV, and 38 kV voltage classes, indoor and outdoor walk-in (protected aisle) configurations, arc-resistant ratings per IEEE C37.20.7, multifunction microprocessor protective relays, and optional IEC 61850 station bus communications.
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.