Call Us To Get Absolutely The Best Service! (703) 690-0449

Electrical Glossary

What happens when you are researching for the best time to maintain or repair your electrical system, and you come across words that you are unfamiliar with and are not explained thoroughly?

Here is your chance to take a look at a glossary of terms that will help you in your electrical repairs and maintenance research.

Amp – The measurement of the electrical current flowing in a circuit at any given moment.

AC – 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.

ACB – Air Circuit Breaker

Access Point – A wireless networked device usually connected to a wireless LAN used to access the wired LAN.

Active Material (Battery) – Material which reacts chemically to produce electrical energy when the cell discharges. The material returns to its original state during the charging process.

Active Power – A term used for power when it is necessary to distinguish among Apparent Power, Complex Power and its components, and Active and Reactive Power.

Adapter – A cord or block style device with different ends that allows different devices to connect.

Air Blast Breakers – A variety of high voltage circuit breakers that use a blast of compressed air to blow-out the arc when the contacts open. Normally, such breakers only were built for transmission class circuit breakers.

AIS – Air Insulated Switchgear

Al – The chemical symbol for aluminum.

Alternating Current – An electric current that reverses direction at regular intervals, having a magnitude that varies continuously in a sinusoidal manner.

American Wire Gage (AWG) – A standard system used in the United States for designating the size of an electrical conductor based on a geometric progression between two conductor sizes.

Ampacity – The current in amperes that a conductor can carry continuously under given conditions of use without exceeding its temperature rating.

Amperage – 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.

Anchor – A device that supports and holds in place conductors when they are terminated at a pole or structure. The anchor is buried and attached to the pole by way of guy wire to counteract the mechanical forces of these conductors.

Arc – A discharge of electricity through air or a gas.

Arc Flash – An arcing fault is the flow of current through the air between phase conductors or phase and neutral or ground. An arcing fault can release tremendous amounts of concentrated radiant energy at the point of the arcing in a small fraction of a second result.

Battery backup – A device providing a short duration of emergency power to be connected to the electrical equipment in case of a power outage.

Boost Charge – A charge applied to a battery which is already near a state of full charge, usually of short duration.

Brownout – Refers to a reduction of voltage on the system. This dims the lights as a means of conserving energy.

Buck – The act of lowering the voltage.

Bundle – Multiple cables used to form one phase of an overhead circuit.

Cable – 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.

Carbon monoxide alarm – This devise detects the presence of carbon monoxide in the air, and monitors the CO concentration in the surrounding environment over time.

CE – Conformite Europeene. A European standard of safety. The CE marking on end products indicates compliance with all applicable directives. 

Conductor – The internal material of a cord that conducts electricity. Copper is the most common material used for electrical wiring. Silver is the best conductor, but is expensive. Because it does not corrode, gold is used for high-quality surface-to-surface contacts.

Connector – A female cord mounted wiring device with the conducting elements recessed behind the mating surface. This type of device is normally wired to be live when nothing is plugged in to it. Therefore, connectors are wired to the source of power.

CSA – Canadian Standards Association, a Canadian product safety and certification organization. Their registered mark shows that a product has been independently tested and certified to meet recognized standards for safety or performance. 

Current – 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”.

Dielectric – Any insulating medium, which intervenes between two conductors and permits electrostatic attraction and repulsion to take place across it.

Dielectric Test – A test that is used to verify an insulation system. A voltage is applied of a specific magnitude for a specific period of time.

DC – 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 electronic devices require DC, and therefore must convert the current into DC before using it.

Direct Current – Electric current in which electrons flow in one direction only. Opposite of alternating current.

Discharge Current – The surge current that is dissipated through a surge arrester.

Distribution System – A term used to describe that part of an electric power system that distributes the electricity to consumers from a bulk power location such as a substation. It includes all lines and equipment beyond the substation fence.

Efficiency (Lighting) – A ratio of light emitted from a luminaire to the light produced by the bare lamp.

Electrical Relay – A device designed to produce sudden predetermined changes in one or more electrical circuits after the appearance of certain conditions in the controlling circuit.

Electricity – The flow of electrons through a conducting medium.

Electromotive Force – Potential causing electricity to flow in a closed circuit.

Extra High Voltage – An electrical system or cable designed to operate at 345kv (nominal) or higher.

Extrusion – The application of a semi-solid rubber or plastic material such as PVC onto a conductor.

Ferrite – Ferrimagnetic ceramic non-conductive compound material used to prevent high frequency electrical noise from entering or exiting the equipment.

Feeder – A three phase distribution line circuit used as a source to other three phase and single phase circuits.

FPI – Fault Passage Indicator.

Frequency Transducer – A transducer used for the measurement of the frequency of an A.C. electrical quantity.

Fuse – A device installed in the conductive path with a predetermined melting point coordinated to load current. Fuses are used to protect equipment from over current conditions and damage.

GFCI – Ground-Fault Circuit-Interrupter. An electrical wiring device that disconnects a circuit whenever it detects that the electric current is not balanced between the energized conductor and the return neutral conductor. Such an imbalance is sometimes caused by current leakage through the body of a person who is grounded and accidentally touching the energized part of the circuit.

Ground – A connection between an electrical device and the Earth or at the voltage defined as zero (in the U.S., called ground; in the UK, called earth).

Ground Fault – An undesired current path between ground and an electrical potential.

Harmonized Code – An international coding system for specifying the attributes of cord voltages, jackets, diameters, etc.

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

High Voltage System – An electric power system having a maximum roo-mean-square ac voltage above 72.5 kilovolts (kv).

Horsepower – A unit of work. When used to show power usage, one horsepower is equivalent to 746 watts.

HV – High Voltage.

ICC – International Color Code. Standard for wire jacket colors; Hot=Brown, Neutral=Blue, Ground=Green/Yellow.

IEC – International Electrotechnical Commission, an international organization that sets standards for electrical products.

Impulse – A current surge.

Impulse Test – Tests to confirm that the insulation level is sufficient to withstand overvoltages, such as those caused by lightning strikes and switching.

Induced Voltage – A voltage produced in a circuit from a nearby electric field.

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

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 referring 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.

Jacket – Outer material layer of a cord.

Jumper – An electrical connection between two points.

Kilowatt – 1000 watts of real power. Expressed at kW.

kVA – 1) Apparent Power expressed in Thousand Volt-Amps. 2) Kilovolt Ampere rating designates the output which a transformer can deliver at rated voltage and frequency without exceeding a specified temperature rise.

Lag – The condition where the current is delayed in time with respect to the voltage in an ac circuit (for example, an inductive load).

Lateral Circuit – A tap-off line to take primary distribution from the main power line to a nearby load center.

Lay Direction – 1) The direction in which the wires of a conductor are twisted. 2) The twist of conductors in a cable.

LED – Light Emitting Diode.

Limit Switch – A protective device used to open or close electrical circuits when certain limits, such as temperature or pressure, are reached.

LV – Low Voltage.

MCC – Motor Control Center.

MCCB – Molded Case Circuit Breaker.

Medium Voltage – An electrical system or cable designed to operate between 1kv and 38kv.

Midget – Referring to an inlet or outlet with a shallow depth. Commonly mounted in areas where space is limited.

NACC – North American Color Code; Hot=Black, Neutral =White, Ground=Green.

Nominal Voltage – A nominal value assigned to a circuit or system for the purpose of conveniently designating its voltage class.

Non-Load break – Refers to a group of rubber insulating products that cannot be separated under load. Also see Loadbreak.

Notching Relay – A relay which switches in response to a specific number of applied impulses.

Off Peak Power – Power supplied during designated periods of low power system demand.

OD – Outer Diameter. The outer diameter of a cord.

Open Link – A fuse used on overhead electrical distribution systems that is held in place by two springs. This device and its holder have generally been replaced by Fused Cutouts where the fuse element in an arc tube.

Outage – The state of a component or part of a power system that is not available for service because of some event associated with the component of power system. These are the longer term events (several seconds to hours) caused by external factors such as trees.

Output Load – The total effective resistance of the circuits and apparatus connected externally across the output terminals.

Overload – The specified maximum magnitude of the input quantity that can be applied for a specified period of time without causing damage.

PCC – Point of Common Coupling.

Plug – A male cord mounted wiring device with the conducting pins protruding and exposed. This type device 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.

Polarized – A plug and connector formed in a way that only allows proper connection.

Power – Rate at which energy is released or consumed, expressed in watts.

Pull – A noun referring to the installation of one or more cables.

Pull Tension – The tension in pounds or kilograms required to pull a cable or wire into a duct or conduit or into an overhead location.

Pulling – The act of installing one or more cables.

Receptacle – 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.

Regulator – A device that is used to control the voltage of a circuit by raising and lowering it. Howard Industries is a manufacturer of Regulators.

Relays – Over-current – Protective relays used on power systems that detect excessive currents and send signals to protective devices, such as power circuit breakers.

ROJ – The designation to Remove Outer Jacket.

SEC – Service Entrance Cable.

Short Circuit – A load that occurs when at ungrounded conductor comes into contact with another conductor or grounded object. 

Slitting – The designation to separate insulated parallel wires.

Stringing – The act of installing overhead electrical wire or conductor.

Stripping – The designation of the removal of the insulation or jacket from a conductor/wire.

Temperature Rating – The maximum temperature at which insulation will maintain its integrity.

Terminal – 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.

Termination – The act of preparing the connection or transition of an insulating cable.

Ultra High Voltage (UFV) – Transmission systems in the ac voltage exceeds 800,000 volts.

Unit Electrical Relay – A single relay that can be used alone or in combinations with others.

UPS – Uninterruptable Power Supply.

USE – Underground Service Entrance conductor or cable.

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

Voltage Drop – The loss of voltage in a circuit when current flows.

Voltage Swells – Voltage Swells are momentary (typically a few milliseconds to a few seconds duration) over-voltage conditions which can be caused by such things as a sudden decrease in electrical load or a short circuit occurring on electrical conductors. Voltage swells.

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

Wye – A three phase, four-wire electrical configuration where each of the individual phases is connected to a common point, the “center” of the Y. This common point normally is connected to an electrical ground.

Looking for more? Have a chat with our experienced electricians and feel free to ask them all of the questions that you’ve been dying to know. They’re there to help you!

Contact Us


peace-of-mind-logo Is It Time To Repair Or Replace? Call The Guy On The Back Of The Truck! LEARN MORE
Why Choose F.H. Furr To Be Your Home Comfort Provider?
We Hire “Absolutely the Best” People
We Hire “Absolutely the Best” People

Industry certifications, drug testing, background checks, and commitment to ongoing training set our technicians apart from the rest.

We Protect Your Home As If It Were Our Own
We Protect Your Home As If It Were Our Own

Our strict protocols on precision and cleanliness ensure your home is always left better than we found it and that your property and belongings are protected.

Industry Exclusive Guarantees
Industry Exclusive Guarantees

At F.H. Furr, you benefit from guarantees you won’t find anywhere else, ensuring you get the best treatment the industry has to offer.

Flat-Rate Pricing – Know Upfront What You’re Paying
Flat-Rate Pricing –
Know Upfront What You’re Paying

We know how tough it is to budget for home services, so we take away the guesswork by guaranteeing a flat-rate price you can count on.

Community Involvement & Charities
Community Involvement & Charities

Our 30+ years of service are only possible because of our community, and we are proud to stay connected through consistent community involvement and charitable donations to local causes.

100% Customer Satisfaction: Past, Present & Future
100% Customer Satisfaction: Past, Present & Future

We aren’t satisfied until our customers are, and our commitment to your satisfaction doesn’t end after just one job. Our 100% guarantee stands for the life of our relationship with all our clients.

See Why Our Customers say we are Absolutely The Best
See Why Our Customers say we are Absolutely
The Best

Excellence, efficiency, and an enduring spirit of service are three of the core values that keep our customers coming back. Our customers’ reviews explain the F.H. Furr difference better than we ever could.

Timothy Klein was our technician who serviced and flushed our two (2) water heaters. Timothy is very knowledgeable, and he explained the procedure in detail. Timothy was extremely professional, courteous, and very neat. We highly recommend him and will ask…
Steve B. Plumbing
FH Furr has been by far the most reputable service and installed company I’ve dealt with. Customer service is great, the technicians show up on time and explain any repairs needed. They also explain costs up front and I have…
MA W. Drains & Sewer