Appendix A. Definitions

Accessible.

Admitting close approach; not guarded by locked doors, elevation, or other effective means.

Ampacity.

Current carrying capacity expressed in amperes.

Approved.

Acceptable to the authority having jurisdiction.

Approved for Purpose.

Approved for a specific purpose, environment, or application by a nationally recognized testing laboratory, inspection agency, or other organization concerned with product evaluation.

Attachment Plug (Cap).

A device which, when installed on a flexible cord and inserted into a receptacle, establishes an electrical connection of the conductors in the flexible cord for those in the receptacle.

Black Box.

Any unit or subassembly installed in equipment that is packaged for ease of removal for ready maintenance.

Bonded.

Securely and mechanically connected by screws, copper braid, or other means.

Captive Screw.

Screw type fastener retained in some manner so that when unscrewed it can not be easily separated from the part it secures.

Circuit Breaker.

A thermal and / or magnetic device providing overcurrent and short-circuit protection.

Circuit Protector (Interrupter).

A thermal and / or magnetic device providing overcurrent protection only.

Commercial Equipment.

Off-the-shelf equipment that is purchased without modification.

Component.

The smallest field replaceable part that serves to form, compose, or make up a unit. Components are assigned part numbers and are identified in materials and spare parts lists.

Conductor.

A substance or body capable of transmitting electricity, e.g., wires.

Conductor, Bare.

Not covered by electrical insulation.

Conductor, Insulated.

Conductor encased within material recognized as insulation by the National Electrical Code ã , Article 310.

Control Circuit.

The circuit that carries the electrical signals which direct the performance of the components that control the power circuit.

Daisy-Chain Connections.

Connections made so that the removal of one component connection causes the interruption of the circuit to another component.

DC Common.

A reference for DC output voltages.

Dead Front.

Without live parts exposed to the person on the operating side of the equipment.

Device. A component which is intended to carry but not use electrical energy.

Disconnecting Means.

A device which disconnects the conductors of a circuit from their supply.

Double Insulation.

Insulation comprised of basic and secondary insulation.

Electrical Control Enclosure.

A compartment (box) designed for supporting and enclosing electrical components and devices which have hazardous potentials or hazardous energy levels.

Emergency Off (EMO).

A name applied to an equipment control switch or circuit switch which, when operated, will stop the operation of the associated equipment and will shut off all hazardous potentials and energy levels outside of the associated main power control enclosure.

Emergency Power Off (EPO).

A name applied to a facilities control switch or circuit which, when operated, will shut off power to all if the equipment in the room / area that it controls.

Emergency Return.

A name applied to an equipment control switch or circuit which, when operated, will stop the operation of associated equipment and will return the machine elements

to the start "home" position.

Emergency Stop (EMS).

A name applied to an equipment control switch or circuit which, when operated, will stop the operation of associated equipment and will bring all moving parts to a stop.

Fail-Safe.

An electrical system so designed that a failure of any component in the system will prevent unsafe operation of the system.

Ferroresonant Regulator.

A magnetic device usually consisting of a primary winding, secondary windings, and an auxiliary winding connected to a capacitor. The device is used to maintain a constant voltage output during line variations.

Fixed Equipment.

Equipment which is fastened or otherwise secured at a specific location.

Ground.

The conducting mass of the earth having zero potential.

Ground Conductor.

A circuit conductor that is intentionally grounded.

Grounding Conductor (EARTH).

A conductor used to connect conductive metal parts and grounded circuit conductors to ground.

Guard (Shield).

A part or attachment to protect personnel from accidentally contacting a potentially hazardous area.

Hazardous Energy Level.

A stored energy level of 20 J or more, or an available continuous power level of 240 VA or more at a potential of 2 V or more.

Hazardous Potential.

A voltage exceeding 42.4 V peak, 30 VRMS, 60 VDC or, in wet areas, 10 VAC or DC.

Inadvertent Contact.

Where it is necessary to reach over, under, around, or in close proximity to any hazards.

Interrupt Current.

The maximum current at rated voltages that a device is intended to interrupt.

Isolation Transformer.

A transformer in which the primary winding(s) are isolated from the other windings such that a insulation breakdown either is unlikely or will not cause a hazardous condition.

Large Equipment.

Multiphase equipment and equipment operating at 120 V with 2 kVA or more main protection.

May.

A recommendation of this document.

Movable Equipment.

Equipment which is:

-under 18 kg (40 lb.) in mass, and not fixed.

-equipped with wheels, casters, or other means to facilitate movement by the operator as required to perform its intended use.

Multioutlet Assembly.

A type of raceway that is designed to hold conductors and receptacles. It must be securely fastened in place.

Multiphase Circuit.

A circuit containing two or more ungrounded conductors.

Multiphase Component.

A component with two or more windings.

Must.

A requirement of this document.

Neutral Conductor.

A circuit conductor used to carry the unbalanced current from the other circuit conductors.

Operator Access Area.

An area to which the operator is given deliberate access or which under normal operating conditions can be accessed without the use of a tool.

Overcurrent.

Any current in excess of the rated current of the equipment.

Portable Equipment.

Equipment which is:

- moved while in operation.

- easily moved from one place to another while plugged into its power source.

Raceways.

A tube or channel used for routing wires, cables, or busbars.

Rated Current.

The input current as specified by the manufacturer.

Rated Voltage.

The input voltage as specified by the manufacturer.

Readily Accessible.

Capable of being easily reached for operation, renewal, or inspections without having to climb over or move obstacles.

Receptacle.

A contact device installed for the connection of a single attachment plug.

Service Area.

All areas of the machine or system to which trained personnel must gain access for service, maintenance, or inspection.

Shall.

A requirement of this document.

Should.

A recommendation of this document, other methods of compliance are acceptable providing they meet the intent of the recommendation.

Signal.

A detectable, physical quantity or impulse by which messages or information ca be transmitted.

Single-Phase Circuit.

A circuit containing one grounded conductor and one ungrounded conductor.

Single-Phase Component.

A component containing only one winding.

Note: A 208 V single-phase (one winding) motor is installed in a multiphase circuit (two ungrounded conductors).

Small Equipment.

Single-phase equipment operating at 120 V or less with up to 2 kVA main protection.

Stationary Equipment.

Denotes either a fixed machine or a machine whose mass exceeds 18 kg (40 lb.) or a machine which can not easily be moved from one place to another.

Strain Relief.

A means to hold a cord or cable securely so that strain is not placed on the electrical terminations.

Subassembly.

An assembly of electrical or electronic components mounted on a panel or chassis which forms a functional unit by it self.

Supply Disconnect (MAIN).

A means of removing all voltages from the machine circuits.

System.

Two or more units that are electrically or mechanically interconnected.

Temporary Power Tap.

A portable assembly consisting of a connector, a length of flexible cord and an enclosure with one or more receptacles. It shall not incorporate any means for permanent mounting.

Thermal Protection.

A protective device which, when properly applied, protects a motor against overheating.

Trip Free.

A design such that a circuit protection device would open a circuit even if the handle mechanism were held closed.

Undervoltage.

Any reduction, interruption or failure of voltage that may cause equipment to stop or cycle incorrectly.

Unit.

A unit is a portion of a system to which an identification type number is applied. It is supported by a frame or frames and is self-enclosed or designed to be attached to another device. Normally a machine is considered to be a unit.

Utilization Equipment.

Equipment which uses electrical energy for mechanical, chemical, heating, lighting, etc.

Ventilated.

Provided with a means to circulate air.

Voltage, AC.

Unless specifically defined as peak, AC voltages are expressed in RMS (Root Mean Square). To convert peak to RMS, multiply by 0.707.

Voltage, Nominal.

A voltage assigned to a circuit or system that serves as a convenient designation of its voltage class, e.g., 24 V AC or DC, 120 / 208 VAC, and 277 / 480 V AC.

Wet Area.

Any area where liquids are visible on the floor.

Wireway.

Sheet metal trough with hinged or removable cover for housing and protecting electric wires and cables.

Wiring Duct.

Plastic trough with removable cover for housing and protecting electric wires and cables.

Within Sight.

Visible and not more than 50 feet distant.

Working Voltage.

Denotes the voltage to which the part under consideration is subjected when the machine is operating at its rated voltage under the conditions of normal use.
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