Article 100 NEC Definitions (Letter S)

Safe Zone
The low probability of damage, typically resulting in only slight swelling of the capacitor case, as identified by the case rupture curve of the capacitor. (460) (CMP—11)

Safety Circuit
The part of a control system that contains one or more devices performing a safety-related function. [79:3.3.95] (CMP—12)
Informational Note: See NFPA 79—2021, Electrical Standard for Industrial Machinery. The terms «safety-related control system» and «safety interlock circuit» are often used in other standards to refer to the safety circuit. The safety circuit can include hardwired, communication, and software-related components.

Sealable Equipment
Equipment enclosed in a case or cabinet with a means of sealing or locking so that live parts cannot be accessed without opening the enclosure. (CMP—1)
Informational Note: The equipment may or may not be operable without opening the enclosure.

Sealed (as applied to hazardous locations)
Constructed so that the equipment is sealed effectively against the entry of an external atmosphere and is not opened during normal operation or maintenance. (CMP—14)
Informational Note: See ANSI/UL 121201, Nonincendive Electrical Equipment for Use in Class I and II, Division 2, and Class III, Divisions 1 and 2 Hazardous (Classified) Locations for further details.

Sealed, Hermetically (Hermetically Sealed)
Sealed against the entrance of an external atmosphere by the fusion of metal to metal, ceramic to metal, or glass to metal. (CMP—14)
Informational Note: See ANSI/UL 121201, Nonincendive Electrical Equipment for Use in Class I and II, Division 2, and Class III, Divisions 1 and 2 Hazardous (Classified) Locations for further details.

Section Sign
A sign or outline lighting system that is shipped as subassemblies, requiring field-installed wiring to complete the overall sign. The subassemblies are either physically joined to form a single sign unit or are installed as separate remote parts of a sign. (600) (CMP—18)

Selected Receptacles
A minimal number of receptacles selected by the healthcare facility’s governing body to provide essential patient care and services during a loss of normal power. [99:3.3.164] (517) (CMP—15)

Self-Contained Therapeutic Tubs or Hydrotherapeutic Tanks
A factory-fabricated unit consisting of a therapeutic tub or hydrotherapeutic tank with all water-circulating, heating, and control equipment integral to the unit. This includes pumps, air blowers, heaters, light controls, sanitizer generators, etc. (680) (CMP—17)

Separable Power Supply Cable Assembly
A flexible cord or cable, including ungrounded, grounded, and equipment grounding conductors, provided with a cord connector, attachment plug, and all other fittings, grommets, or devices installed for delivering energy from the electrical supply to the truck or transport refrigerated unit (TRU) flanged surface inlet. (626) (CMP—12)

Separately Derived System
An electrical power supply output, other than a service, with no direct connection(s) to conductors of any other electrical source other than those established by grounding and bonding connections. (CMP—5)

Service
The conductors and equipment connecting the serving utility to the premises’ wiring system. (CMP—10)

Service Conductors
The conductors from the service point to the service disconnecting means. (CMP—10)

Service Conductors, Overhead
Overhead conductors between the service point and the first point of connection to the service-entrance conductors at the building or other structure. (CMP—10)

Service Conductors, Underground
Underground conductors between the service point and the first point of connection to the service-entrance conductors in a terminal box, meter, or other enclosure, inside or outside the building wall. (CMP—10)
Informational Note: If there’s no terminal box, meter, or other enclosure, the point of connection is considered to be the entrance point of the service conductors into the building.

Service Drop
The overhead conductors between the serving utility and the service point. (CMP—10)

Service-Entrance Conductor Assembly
Multiple single-insulated conductors twisted together without an overall covering, other than an optional binder that only keeps the conductors together. (CMP—6)

Service-Entrance Conductors
The service conductors between the terminals of the service equipment and the service drop, overhead service conductors, service lateral, or underground service conductors. (CMP—10)
Informational Note: If service equipment is located outside the building walls, there may be no service-entrance conductors, or they may be entirely outside the building.

Service Equipment
Equipment containing circuit breakers or switches and fuses that constitute the main control and disconnect of the serving utility. (CMP—10)

Service Equipment, Mobile Home
The equipment containing disconnecting means, overcurrent protective devices, and receptacles or other means for connecting a mobile home feeder assembly. (550) (CMP—7)

Service Lateral
The underground conductors between the utility electric supply system and the service point. (CMP—10)

Service Point
The point of connection between the serving utility’s facilities and the premises’ wiring. (CMP—10)
Informational Note: The service point marks the demarcation where the utility’s responsibility ends, and the premises’ wiring begins. The location of the service point is typically determined by the serving utility based on service conditions.

Servicing
The process of following manufacturer’s instructions or industry standards to analyze, adjust, or perform actions on equipment to preserve or restore its operational performance. (CMP—1)
Informational Note: Servicing includes maintenance and repair activities.

Shore Power
The electrical equipment required to power a floating vessel, including receptacles and cords. (555) (CMP—7)

Shoreline
The farthest extent of standing water under the applicable conditions, determining the electrical datum plane for a specified body of water. (682) (CMP—17)

Short Circuit
An abnormal connection (including an arc) of relatively low impedance, whether accidental or intentional, between two or more points of different potential. (CMP—10)

Short-Circuit Current Rating
The prospective symmetrical fault current at a nominal voltage to which an apparatus or system can be connected without sustaining damage exceeding defined acceptance criteria. (CMP—10)

Show Window
Any window, including above-door windows, used or designed for displaying goods or advertising material, whether fully or partly enclosed, or open at the rear. (CMP—2)

Sign, Photovoltaic (PV) Powered (PV Powered Sign)
A complete sign powered by solar energy, consisting of all components and subassemblies for installation as an off-grid, on-grid interactive, or non-grid interactive system. (600) (CMP—18)

Sign Body
A part of a sign that provides weather protection but is not an electrical enclosure. (600) (CMP—18)

Signaling Circuit
An electrical circuit that energizes signaling equipment. (CMP—3)

Simple Apparatus
An electrical component or combination of components with well-defined parameters that does not generate more than 1.5 volts, 100 mA, and 25 mW, or a passive component that does not dissipate more than 1.3 watts and is compatible with the intrinsic safety of the circuit. (CMP—14)
Informational Note 1: Examples include passive components (switches, connectors, resistance devices, LEDs), simple circuit components (capacitors, inductors), and energy sources (thermocouples, photocells).
Informational Note 2: For further information, refer to ANSI/UL 913 and ANSI/UL 60079-11.

Single-Pole Separable Connector
A device installed at the ends of portable, flexible, single-conductor cable to establish connections or disconnections between two cables or between a cable and a panel-mounted separable connector. (CMP—18)

Site-Isolating Device
A pole-mounted disconnecting means installed at the distribution point for isolation, system maintenance, emergency disconnection, or optional standby systems. (547) (CMP—7)

Skeleton Tubing
Neon tubing that serves as the sign or outline lighting itself, not attached to an enclosure or sign body. (600) (CMP—18)

Slip
A berthing space between piers, wharves, or docks; the water areas associated with boat occupation. [303:3.3.21] (555) (CMP—7)
Informational Note: See the definition of «Berth» for additional information.

olid-State Phase-Control Dimmer

A solid-state dimmer where the steady-state current waveform does not follow the shape of the applied voltage, resulting in a nonlinear waveform. (CMP—15)

Solid-State Sine Wave Dimmer

A solid-state dimmer where the steady-state current waveform matches the shape of the applied voltage, producing a linear waveform. (CMP—15)

Spa or Hot Tub

A hydromassage pool or tub used for recreational or therapeutic purposes, usually equipped with a filter, heater, and motor-driven blower. It can be installed indoors or outdoors. Typically, it is not designed to be drained after each use. (680) (CMP—17)

Spa or Hot Tub, Packaged Equipment Assembly

A factory-made unit that includes water-circulating, heating, and control equipment mounted on a common base, designed to operate a spa or hot tub. (680) (CMP—17)

Spa or Hot Tub, Self-Contained

A factory-made unit that contains all necessary water-circulating, heating, and control equipment integrated into the spa or hot tub vessel. (680) (CMP—17)

Spa or Hot Tub, Storable

A spa or hot tub designed for installation above ground and intended to be stored when not in use. It is easily relocatable. (680) (CMP—17)

Space

A portion of a healthcare facility designated for a specific function, as determined by the facility’s governing body. (517) (CMP—15)

Special Permission

The written consent granted by the authority having jurisdiction for specific activities or installations. (CMP—1)

Special Protection «s»

A type of protection used for equipment that cannot be fully assessed by standard types of protection due to operational or functional limitations but can still demonstrate sufficient equipment protection. (CMP—14)
Informational Note: See ANSI/UL 60079-33 for further details.

Special-Purpose Multi-Circuit Cable System

A portable branch-circuit distribution system composed of trunk cables and optional breakout assemblies or multi-circuit outlet enclosures. (520) (CMP—15)

Spider (Cable Splicing Block)

A device with insulated busbars used for splicing or distributing power to portable cables and cords. (530) (CMP—15)

Spin Down

A condition where the energy in a flywheel energy storage system (FESS) is dissipated, and the flywheel rotor gradually slows to a stop. (706) (CMP—13)
Informational Note: A complete stop occurs gradually due to friction forces.

Splash Pad

A recreational fountain with a water depth of no more than 25 mm (1 inch), not intended for hygienic rinsing before entering pools or spas. (680) (CMP—17)

Spray Area

An area in which flammable or combustible vapors, mists, residues, or dusts are present due to spray processes, including spray booths, spray rooms, and exhaust systems. (CMP—14)
Informational Notes:

  1. Unenclosed spray areas are those located outside buildings or in localized operations within larger rooms.
  2. See definitions for spray booths and finishing workstations for additional clarification.

Spray Area, Outdoor

An outdoor spray area that is either open or partially covered but still allows for proper heat dissipation and firefighting access. (CMP—14)

Spray Area, Unenclosed

A spray area not confined by a spray booth or room. (CMP—14)

Spray Booth

A ventilated enclosure used for spray applications that confines the material being sprayed and directs it to an exhaust system. (CMP—14)

Spray Room

A fully enclosed, power-ventilated room used for open spraying of flammable or combustible materials, with a specific fire resistance rating. (CMP—14)

Stage Effect (Special Effect)

Electrical or electromechanical equipment used to simulate visual or audible effects, such as wind machines or lightning simulators. (CMP—15)

Stage Equipment

All equipment integral to stage production, including lighting, audio, special effects, rigging, and more. (520) (CMP—15)

Stage Lighting Hoist

A motorized device used to lift and lower luminaires for stage lighting, with wiring for connection to branch circuits. (520) (CMP—15)

Stage Property

An item used for visual purposes in movie or TV productions, excluding painted scenery and costumes. (530) (CMP—15)

Stage Set

A temporary arrangement of scenery and properties for a specific scene in a production. (CMP—15)

Stage Switchboard, Fixed

A permanent switchboard or panelboard with dimmers or relays used to supply power to stage equipment. (CMP—15)

Stage Switchboard, Portable

A portable unit containing dimmers or relays with associated protective devices, used for stage equipment. (520) (CMP—15)

Stand Lamp

A portable stand with a general-purpose luminaire used for stage or studio lighting. (520) (CMP—15)

Stand-Alone System

A system not connected to an electric power production and distribution network. (CMP—4)

Stationary (as applied to equipment)

Equipment that remains in a fixed location during normal use. (680) (CMP—17)

Storage, Dry Stack

A facility for storing small boats in defined slots, arranged horizontally and vertically. (555) (CMP—7)

Stored-Energy Power Supply System (SEPSS)

A complete EPSS powered by a stored-energy electrical source. (CMP—13)

Stranding, Compact

A method where conductor strands are pressed together to reduce gaps, resulting in a smaller diameter compared to concentric stranded conductors. (CMP—6)

Stranding, Compressed

A conductor stranding method in which the outer strands are pressed together, making the diameter smaller than a concentric stranded conductor but larger than a compact stranded conductor. (CMP—6)

Stranding, Concentric

A conductor consisting of a central strand surrounded by helically laid layers of strands. (CMP—6)

Strip Light

A luminaire consisting of multiple lamps arranged in a row. (520) (CMP—15)

Structure

An entity that is built or constructed, excluding equipment. (CMP—1)

Structure, Relocatable

A factory-built structure designed for transport and use without a permanent foundation. (545) (CMP—7)

Subassembly

A component or segment of a sign or lighting system that, when assembled, forms a complete unit. (600) (CMP—18)

Substation

An assemblage of equipment used for the distribution, switching, or modification of electric energy. (CMP—9)

Supervisory Control and Data Acquisition (SCADA)

An electronic system used for monitoring and controlling critical operations power systems. (CMP—13)

Support Areas

Areas, other than fixed offices, that support production but are not used for image capture, such as storage, workspaces, and portable facilities. (530) (CMP—15)

Surge Arrester

A device designed to limit surge voltages by diverting surge currents and preventing follow-up currents, ensuring repeatable protection. (CMP—10)

Surge-Protective Device (SPD)

A Surge-Protective Device (SPD) is designed to limit transient voltages by diverting or limiting surge current. It prevents the continued flow of follow current while being capable of repeating these functions. SPDs are categorized as follows:

  • Type 1: Permanently connected SPDs intended for installation between the secondary of the service transformer and the line side of the service disconnect overcurrent device.
  • Type 2: Permanently connected SPDs intended for installation on the load side of the service disconnect overcurrent device, including those located at the branch panel.
  • Type 3: Point of utilization SPDs.
  • Type 4: Component SPDs, including discrete components and assemblies.

Informational Note: Refer to UL 1449, Standard for Surge Protective Devices, for more details.


Suspended Ceiling Grid

A Suspended Ceiling Grid is a system that serves as a support structure for a finished ceiling surface and other utilization equipment. This system is referenced in Section 393.


Switch, General-Use

A General-Use Switch is intended for use in general distribution and branch circuits. It is rated in amperes and capable of interrupting its rated current at its rated voltage.


Switch, General-Use Snap

A General-Use Snap Switch is a type of general-use switch that can be installed in device boxes or on box covers, or used in conjunction with wiring systems recognized by this Code.


Switch, Isolating

An Isolating Switch is used to isolate an electrical circuit from its power source. This switch has no interrupting rating and is meant to operate only after the circuit has been opened by another means.


Switch, Motor-Circuit

A Motor-Circuit Switch is rated in horsepower and capable of interrupting the maximum operating overload current of a motor with the same horsepower rating at the rated voltage.


Switchboard

A Switchboard is a large panel, frame, or assembly containing switches, overcurrent protective devices, buses, and usually instruments. These assemblies are accessible from the front, rear, or sides and are not intended to be installed in cabinets.


Switchgear

Switchgear is an assembly completely enclosed with sheet metal (except for ventilating openings and inspection windows) that contains primary power circuit switching, interrupting devices, or both. It may also include control and auxiliary devices. Access is provided via doors or removable covers.

Informational Note: Switchgear rated below 1000V may be referred to as «low-voltage power circuit breaker switchgear,» and switchgear rated over 1000V may be identified as «metal-enclosed» or «metal-clad» switchgear. Switchgear can be non-arc-resistant or arc-resistant.


Switching Device

A Switching Device is used for closing, opening, or both, one or more electrical circuits. It is applied to equipment rated over 1000V AC or 1500V DC.


Cutout

A Cutout is an assembly of a fuse support with a fuseholder, fuse carrier, or disconnecting blade. The fuseholder may include a fuse link, or the fuse carrier may act as the disconnecting blade with a nonfusible member.


Disconnecting Switch (or Isolating Switch)

A Disconnecting Switch is a mechanical switching device used to isolate a circuit or equipment from a power source.


Interrupter Switch

An Interrupter Switch is a switching device capable of making, carrying, and interrupting specified currents.


Oil-Filled Cutout

An Oil-Filled Cutout is a cutout in which the fuse support and its fuse link or disconnecting blade are mounted in oil, providing arc interruption by severing the fuse link or opening the contacts under oil.


Oil Switch

An Oil Switch is a switching device with contacts that operate under oil, askarel, or other suitable liquid for arc suppression.


Regulator Bypass Switch

A Regulator Bypass Switch is designed to bypass equipment that controls voltage levels or related circuit characteristics.


System Isolation Equipment

System Isolation Equipment is a redundantly monitored, remotely operated contactor-isolating system. It provides disconnection or isolation and can be operated remotely from multiple locations via lockout switches that can be padlocked in the «off» position.


Summary Table of Terms and Definitions:

TermDefinition
Safe ZoneLow probability of capacitor damage, identified by the rupture curve.
Safety CircuitPart of a control system performing safety-related functions.
Sealable EquipmentEquipment enclosed with sealing/locking to prevent live part access.
Sealed (Hazardous Locations)Equipment sealed against external atmosphere entry.
Sealed, Hermetically (Hermetically Sealed)Sealed against external atmosphere using fusion of materials.
Section SignA sign that requires field-installed wiring to complete.
Selected ReceptaclesReceptacles providing essential care services during power loss.
Self-Contained Therapeutic TubsFactory-fabricated therapeutic tubs with integrated equipment.
Separable Power Supply CableFlexible cable assembly with connectors for energy delivery.
Separately Derived SystemElectrical power supply not directly connected to any other source.
ServiceConductors and equipment connecting utility to premises wiring.
Service ConductorsConductors from service point to service disconnecting means.
Service Conductors, OverheadOverhead conductors between service point and first connection.
Service Conductors, UndergroundUnderground conductors between service point and first connection.
Service DropOverhead conductors between utility and service point.
Service-Entrance Conductor AssemblyMultiple single-insulated conductors twisted without overall covering.
Service EquipmentEquipment for main control and disconnect from the serving utility.
Service Equipment, Mobile HomeEquipment for connecting a mobile home feeder assembly.
Service LateralUnderground conductors between utility supply and service point.
Service PointThe point of connection between the utility and premises’ wiring.
ServicingActions to maintain or restore equipment’s operational performance.
Shore PowerElectrical equipment to power a floating vessel.
ShorelineFarthest extent of standing water to determine the electrical datum plane.
Short CircuitLow impedance connection between points of different potential.
Short-Circuit Current RatingThe prospective fault current an apparatus can withstand without damage.
Show WindowWindow designed for displaying goods or advertising material.
PV Powered SignSign powered by solar energy with all required components.
Sign BodyPart of the sign providing weather protection but not electrical.
Signaling CircuitCircuit energizing signaling equipment.
Simple ApparatusComponents with well-defined parameters for low power usage.
Single-Pole Separable ConnectorDevice to connect/disconnect single-conductor cables.
Site-Isolating DevicePole-mounted disconnecting means for system maintenance or isolation.
Skeleton TubingNeon tubing used as sign or outline lighting.
SlipWater areas associated with boat occupation.
TermDefinition
Solid-State Phase-Control DimmerA solid-state dimmer with nonlinear current waveform.
Solid-State Sine Wave DimmerA solid-state dimmer with a linear current waveform.
Spa or Hot TubA hydromassage pool or tub with filter, heater, and blower.
Spa or Hot Tub, Packaged Equipment AssemblyFactory-made unit with integrated spa or hot tub equipment.
Spa or Hot Tub, Self-ContainedIntegrated spa unit with all necessary water systems.
Spa or Hot Tub, StorableAbove-ground spa designed for storage when not in use.
SpaceA designated area in a healthcare facility for a specific function.
Special PermissionWritten consent from the authority having jurisdiction.
Special Protection «s»Protection for equipment with operational limitations.
Special-Purpose Multi-Circuit Cable SystemPortable distribution system with multi-circuit outlets.
Spider (Cable Splicing Block)Device with insulated busbars for portable cable power distribution.
Spin DownCondition of energy dissipation as a flywheel slows to a stop.
Splash PadA recreational fountain with no more than 25 mm of water depth.
Spray AreaAn area where flammable materials are present due to spray processes.
Spray BoothA ventilated enclosure for spraying operations.
Spray RoomA fully enclosed room for open spraying of flammable materials.
Stage Effect (Special Effect)Equipment used to simulate visual or audible effects.
Stage EquipmentEquipment integral to stage production, including lighting and audio.
Stage Lighting HoistMotorized device for raising and lowering stage luminaires.
Stage PropertyVisual elements used in film or TV production.
Stage SetTemporary arrangement of scenery for a specific production scene.
Stage Switchboard, FixedPermanent switchboard used to supply stage equipment.
Stage Switchboard, PortablePortable switchboard for supplying stage equipment.
Stand LampPortable lamp used for general lighting on stage or in studios.
Stand-Alone SystemSystem not connected to a power production and distribution network.
Stationary (as applied to equipment)Equipment that remains fixed during normal use.
Storage, Dry StackFacility for storing boats in horizontal and vertical slots.
Stored-Energy Power Supply System (SEPSS)EPSS powered by stored energy.
Stranding, CompactStranding method that reduces gaps between strands, resulting in a smaller conductor diameter.
Stranding, CompressedStranding method that presses outer strands together.
Stranding, ConcentricA conductor with a central strand surrounded by layers of helically laid strands.
Strip LightLuminaire with multiple lamps arranged in a row.
StructureAnything built or constructed, excluding equipment.
Structure, RelocatableTransportable structure not requiring a permanent foundation.
SubassemblyComponent parts that form a complete unit when assembled.
SubstationEquipment for distribution, switching, or modifying electric energy.
Supervisory Control and Data Acquisition (SCADA)Electronic system for monitoring and controlling power systems.
Support AreasAreas supporting production activities in a facility.
Surge ArresterDevice designed to limit surge voltages and prevent follow-up currents.
TermDefinition
Surge-Protective Device (SPD)A device to limit transient voltages by diverting or limiting surge current and preventing follow current.
Suspended Ceiling GridA support system for a finished ceiling surface and other equipment.
Switch, General-UseA switch used for general distribution and branch circuits, rated in amperes.
Switch, General-Use SnapA form of general-use switch designed for installation in device boxes or wiring systems.
Switch, IsolatingA switch intended to isolate a circuit from the power source, with no interrupting rating.
Switch, Motor-CircuitA switch capable of interrupting motor overload currents of the same horsepower rating.
SwitchboardAn assembly of switches, overcurrent protection, and buses mounted on panels.
SwitchgearAn enclosed assembly containing switching, interrupting devices, and buses.
Switching DeviceA device to close, open, or both, electrical circuits over 1000V AC or 1500V DC.
CutoutAn assembly with a fuseholder or disconnecting blade, potentially including a fuse link.
Disconnecting SwitchA mechanical device for isolating circuits from power sources.
Interrupter SwitchA switching device capable of making, carrying, and interrupting currents.
Oil-Filled CutoutA cutout immersed in oil to assist with arc interruption.
Oil SwitchA switch that operates under oil or other liquid for arc suppression.
Regulator Bypass SwitchA switch used to bypass voltage-regulating equipment.
System Isolation EquipmentA system providing remote disconnection/isolation with lockout switches.
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