Knowledge Center


Common Electrical Construction Terms


Alternating Current. Electric current that rises from zero to a maximum in one direction, falls to zero and then rises to a maximum in the opposite direction, and then repeats another cycle.

Access Flooring

A flooring system with modular panels that are raised above the floor slab, typically on 3” to 12” supports. Electrical conduit and data cabling are routed below the flooring panels and connected to floor monuments.


Amps/Amperes/Ampacity/Rated Amperage -measurement of the flow rate of electricity. If you think in terms of water through a hose, amperage would be a measure of water volume flowing through the hose.


A device in fluorescent lamps that regulates the amps of electrical current and voltage flowing through the fluorescent lamp. Ballasts can be magnetic or electronic. 

Branch Circuit

A single circuit carrying electrical current to office furniture and equipment. Consists of wires connected between the building’s electrical service panel (circuit breakers) and the electrical outlets.


A cable is a set of wires, usually encased in an outer protective jacket. A “cord” would be a cable by this definition so far, but a cable is part of a permanent installation; a cord is more flexible and often has a plug end for a portable appliance or lamp.

Cable Harness

A string of cables and/or wires which transmit informational signals or operating currents (energy). The cables are bound together by clamps, cable ties, cable lacing, sleeves, electrical tape, conduit, a weave of extruded string, or a combination thereof.

Cable Tray

A bridge that allows safe transport of wires across open spans and gives protection against the overheating and fire buildup problems. This is a cable management system that is available in a variety of sizes and styles.


A complete path for electrical current flowing from the building power source to the equipment being powered and back to the power source. The “hot” conductor of a circuit carries 120-volt power to the equipment; the “neutral” conductor carries it back to the source. The “ground” conductor provides a safe escape route for power in the event of short circuits or other problems. Circuits are rated according to the number of amps they can accommodate. The total number of amps required by all the equipment in a furniture installation will dictate the number of circuits required.

Circuit Breaker

An automatic device for stopping the flow of current in an electric circuit. To restore service, the circuit breaker must be reset (closed) after correcting the cause of the overload or failure.


Metal or non-metallic tubing — available in either rigid or flexible varieties — used to route and protect electrical wires and communication cables.


The rate of flow of electrical energy through a conductor or wire, comparable to the amount of water flowing in a pipe. Electric current is measured in amperes or “amps”


Direct Current. Current which moves in a single direction in a steady flow. Normal household electricity is alternating current (AC) which repeatedly reverses its direction. However, many electronics devices require DC, and therefore must convert the current into DC before using it.


A method of project delivery in which the construction team is engaged by the owner to collaborate with the architect or engineer during the design phase. It is intended to reduce the cost and time for construction, improve constructability and add value.


A method of project delivery in which one entity - the design-build team - works under a single contract with the project owner to provide design and construction services. One entity, one contract, one unified flow of work from initial concept through completion.


All circuit conductors between the service equipment, the source of a separately derived system, or other power supply source and the final branch-circuit overcurrent device.

Floor Duct

An under-floor system of wireways which brings electrical wires and data cabling to floor monuments. This system provides many of the benefits of access flooring but often costs less.

Floor Monument/Floor Access

An electrical outlet located on or under the floor’s surface. Flush “under floor” access consists of a flush access door that may be lifted to access the electrical and/or data cable junction boxes.


A circuit interrupting device consisting of a strip of wire that melts and breaks an electric circuit if the current exceeds a safe level. To restore service, the fuse must be replaced using a similar fuse with the same size and rating after correcting the cause of failure.


A device that converts mechanical energy to electrical energy for use in an external circuit. The source of mechanical energy may vary widely from a hand crank to an internal combustion engine. Generators provide nearly all the power for electric power grids.

GFCI (Ground Fault Circuit Interrupters)

A device intended for the protection of personnel that functions to de-energize a circuit or portion thereof within an established period of time when a current to ground exceeds some predetermined value that is less than that required to operate the overcurrent protective device of the supply circuit.

Ground or Earth

The reference point in an electrical circuit from which voltages are measured, a common return path for electric current, or a direct physical connection to the Earth.

Ground Fault

An unintentional, electrically conductive connection between an ungrounded conductor of an electrical circuit and the normally non–current-carrying conductors, metallic enclosures, metallic raceways, metallic equipment, or earth.

Ground Fault Current Path

An electrically conductive path from the point of a ground fault on a wiring system through normally non–current-carrying conductors, equipment, or the earth to the electrical supply source.


Measurement of frequency, equaling one cycle per second, U.S. devices are typically 60 Hertz and international devices are typically 60 hertz.

IBEW (International Brotherhood of Electrical Workers)

The IBEW represents approximately 750,000 active members and retirees who work in a wide variety of fields, including utilities, construction, telecommunications, broadcasting, manufacturing, railroads and government.  The IBEW has members in both the United States and Canada and stands out among the American unions in the AFL-CIO because it is among the largest and has members in many skilled occupations.


The material that encases a conductor preventing leakage of current from a conductor.


An apparatus that converts direct current into alternating current.

IP Rating

Ingress Protection Rating, a two-digit code, and an optional letter, specifying the level of protection from foreign objects with the first digit referring to protection from solids and the second digit refer- ring to protection from liquids. The optional letter can be appended to classify only the level of protection against access to hazardous parts by persons or to provide additional information related to the protection of the device.


Outer material layer of a cord.

Junction Box

An electrical construction box that provides a space for the connection or splicing of the electrical conductors. Connections inside the junction box are usually accomplished with twist-on electrical wire nuts.


The amount of power (amps) consumed by an electrical circuit or device. Loads are usually expressed in amps, but sometimes in watts.

NECA (National Electrical Contractors Association)

The electrical contractor’s trade association in the United States that supports the businesses that bring power, light, and communication technology to buildings and communities. Through advocacy, education, research, and standards development, NECA works to advance the electrical contracting industry.


National Electrical Manufacturers Association, an organization based in the U.S. that sets many common standards used in electrical products.


Original Equipment Manufacturer.

Open Circuit

A condition where the current flow through a conductor is interrupted by a missing or damaged component.


Occupational Safety and Health Association.  An agency of the United States Department of Labor whose purpose is to prevent work-related injuries, illnesses, and occupational fatality by issuing and enforcing standards for workplace safety and health.


Operation of equipment in excess of normal, full-load rating, or of a conductor in excess of rated ampacity that, when it persists for a sufficient length of time, would cause damage or dangerous overheating. A fault, such as a short circuit or ground fault, is not an overload.

Parallel Circuit

A circuit in which there are multiple paths for electricity to flow. Each load connected in a separate path receives the full circuit voltage, and the total circuit current is equal to the sum of the individual branch currents.Rectifier — An electrical device that converts an alternating current into a direct one by allowing a current to flow through it in one direction only.


A very short patch cable or wiring adapter. Primarily used in the automotive industries where a longer cable assembly is not needed.

Plenum, Plenum-Rated

Plenum refers to an air chamber in a heating, ventilation, and air conditioning (HVAC) system or to the space between a dropped ceiling and the floor above. The plenum space is often used to route conductors and cables. Plenum-rated describes a special type of conductor or cable which is approved/rated for use in a building plenum space. These types of conductors are specially insulated, giving them low flame- and smoke-producing properties. Non-plenum rated cables may also be routed in a plenum space, if they are enclosed in conduit that provides fire-resistant properties.


A male cord mounted wiring device with the conducting pins protruding and exposed. This type de- vice should never be wired to make the exposed pins live while unplugged. Therefore, plugs are always dead until they are plugged into a power source such as a wall outlet or generator outlet.


A female flange mounted wiring device with the conducting elements recessed behind the mating surface. Often referred to as an outlet. This type of device is normally wired to be live when nothing is plugged in to it. Therefore, receptacles are wired to the source of power.

Series Circuit

A circuit in which there is only one path for electricity to flow. All of the current in the circuit must flow through all of the loads completing its path to the source of supply.

Series Parallel Circuit

An electric current containing groups of parallel connected receptive devices, the groups being arranged in the circuit in series; a series multiple circuit.

Service Lateral

The underground service conductors between the street main – including risers – and the first point of connection to the service-entrance conductors in a terminal box, meter, or other enclosure.

Short Circuit

A fault in an electric circuit or apparatus due usually to imperfect insulation, such that the current follows a by-path and inflicts damage or is wasted.


The combination of electrical disconnect switches, fuses or circuit breakers used to control, protect and isolate electrical equipment. Switchgear is used both to de-energize equipment to allow work to be done and to clear faults downstream.


A terminal is the point at which a conductor from an electrical component, device or network comes to an end and provides a point of connection to external circuits. A terminal may simply be the end of a wire or it may be fitted with a connector or fastener. The connection may be temporary, as for portable equipment, or may require a tool for assembly and removal, or may be a permanent electrical joint between two wires or devices.

Three-Phase Power

A type of electrical system or circuit that utilizes three separate sources of alternating current. The three sources are electrically related to each other by a 120° phase separation. A 3-phase circuit — the most common type in commercial properties in the United States — may consist of four or more conductors.

Title 24

The California Title 24 Building Energy Efficiency Standards are designed to ensure new and existing buildings achieve energy efficiency and preserve outdoor and indoor environmental quality. These measures (Title 24, Part 6) are listed in the California
Code of Regulations.


A semiconductor device with three connections, capable of amplification in addition to rectification.


Underwriters Laboratories, an independent non-profit product safety and certification organization.

UPS (Uninterruptible Power Supply)

An electrical device that supplies separate or supplemental power to equipment in the event of a power outage. The UPS uses a battery and electronic voltage-generating circuits to supply power during brief power interruptions, usually up to 10 minutes.


The force or “push” driving electrical energy through a conductor or wire that can be compared to the pressure of water in a pipe.


A unit of power, defined as one joule per second. Wattage is calculated as Voltage x Amperage.


A plastic molding designed to be attached directly to the wall with wires hidden inside of it. The main purpose of wire mold is to conceal wires in an attractive manor in situations where it is not possible to run the wire in any other fashion.

Additional Resources