References: Energy Information Administration, Pennsylvania Public Utility Commission, Tampa Electric, Northeast Utilities

Click on the alphabet letter to go directly to the section you want.

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

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Amps
AMPS are the amount of electricity or current flowing through a wire, similar to the flow of water through a pipe. A typical residential service capacity is 60 amps.

Arcing (Overheating)
ARCING is the flow of electricity through the air from one conductor to another. Arcing can produce visible flashes and flames along with a crackling sound. Arcing is generally caused by overloaded electrical equipment.

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Brownout
A BROWNOUT is a reduction in voltage and/or power when demand for electricity exceeds generating capacity.

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Cable
A CABLE is a wire or bundle of wires which is a fully insulated conductor of electricity. A cable can be installed overhead or underground.

Capability
CAPABILITY is the maximum electrical load which a generating station or electrical equipment can carry under specific conditions for a given period of time, without exceeding approved limits of temperature and stress.

Capacitor
A CAPACITOR is an electrical device that helps improve the efficiency of the flow of electricity by reducing energy losses. Capacitors are installed in substations and on utility poles.

Capacity
CAPACITY is the maximum load of electricity that equipment can carry.

Circuit
A CIRCUIT is a path through which electricity travels.

Circuit Breaker
CIRCUIT BREAKERS automatically stop the flow of electricity when it senses too much current or an abnormal condition. Circuit breakers are located in substations and on transmission and distribution lines throughout Duquesne Light's system. Once a circuit breaker opens, it must be reset before the flow of power can be restored.

Conductor
A CONDUCTOR is a material or object through which an electric current can flow. The most common conductor is an electrical wire.

Conduit
A CONDUIT is a tube, duct or pipe used for protecting wires.

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Daily Peak
The DAILY PEAK is the greatest amount of electricity demanded during a one-hour period in a day.

Demand
DEMAND refers to the total amount of electricity – measured in kilowatts – used at any given time.

Distribution System
The DISTRIBUTION SYSTEM is comprised of the wires, poles, transformers, substations and other equipment used to deliver electricity to customers. The Distribution System delivers power at voltage levels that can be used in homes and businesses.

Distribution Line
A DISTRIBUTION LINE is a power line that delivers electricity directly to customers. Distribution lines carry power at less than 69,000 volts.

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Electric Distribution Company
The ELECTRIC DISTRIBUTION COMPANY is the regulated utility that owns and operates the power lines and equipment necessary to deliver purchased electricity to customers.

Electric Generation Supplier
An ELECTRIC GENERATION SUPPLIER is a company, generator, broker, marketer, aggregator or other entity licensed by the Public Utility Commission to sell power to customers. The electricity is transported to customers by the regulated Electric Distribution Company.

Electricity
ELECTRICITY is electric current used as a source of power.

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Fault
A FAULT is a failure or interruption in an electrical circuit.

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Grid
The GRID is the network of transmission facilities over which electricity travels.

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Insulator
An INSULATOR is a material or object through which electricity cannot easily pass. Some common insulators are porcelain, glass, rubber and wood.

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Kilowatt
A KILOWATT is a measure of electrical power equal to 1,000 watts. A watt is the rate at which electricity is generated or consumed. Ten 100-watt bulbs use one kilowatt of electricity.

Kilowatt-hour
A KILOWATT-HOUR is a basic unit of electricity equal to one kilowatt or 1,000 watts of power used for one hour.

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Lightning Arrestor
A LIGHTNING ARRESTOR is used to protect poles, wires, cables, transformers, and other electrical equipment from lightning surges by carrying the charge to the ground.

Line Crew
A LINE CREW is a team – usually two individuals – of trained workers who service and repair electric lines and equipment.

Load
LOAD is the amount of power delivered to customers. Load is created by the power demands of customers.

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Megawatt
A MEGAWATT is one million watts or 1,000 kilowatts.

Mobile Substation
A MOBILE SUBSTATION is a movable substation, used when a substation is unavailable or additional power is needed.

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Network
A NETWORK is a system of transmission and distribution lines cross-connected to provide multiple power feeds to an area. A network is usually installed in urban areas. Networks make it possible to restore power quickly to customers by switching them to another circuit.

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Off-Peak
OFF-PEAK is the time period during which demand for electricity is relatively low. Off-peak periods typically occur at night and on weekends.

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Pad-Mount Transformer
A PAD-MOUNTED TRANSFORMER is a large metal cabinet located on the ground in a neighborhood or business area that is served by underground electrical lines. As electricity passes through the transformer, the power is converted to voltages that can be used in homes or businesses.

Peak Demand
PEAK DEMAND is the maximum amount of electricity necessary to supply customers. Peak periods fluctuate by season. Peak demand generally occurs in the morning during the winter and in the afternoon during the summer.

Planned Electric Outage
A PLANNED ELECTRIC OUTAGE is a scheduled interruption of service to allow a repair crew to perform work that cannot be done while the lines are energized.

Pole-mounted Transformer
A POLE-MOUNTED TRANSFORMER is a transformer mounted on a utility pole that decreases the voltage of electricity so that it can be used in homes and businesses.

Primary Distribution Lines (Primaries)
PRIMARIES are distribution lines that carry the highest levels of distribution voltage. They are usually located at the highest position on utility poles.

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Reclosure
A RECLOSURE is a switch which functions like a circuit breaker to stop the flow of electricity in a wire or device to protect primary circuits from faults. A reclosure will automatically restore the circuit if the fault is temporary. Temporary faults are often caused by tree branches touching lines or small animals that come in contact with energized electrical equipment.

Relay
A RELAY is a device that operates a switch by remote control. A relay triggers interruption of a circuit when a fault is detected.

Reliability
RELIABILITY is the assurance of a continuous supply of electricity for customers at the proper voltage and frequency.

Rolling Blackout
ROLLING BLACKOUTS are controlled, temporary interruptions of electrical service initiated by a utility to meet heavy peak demands when there is an extreme deficiency in the supply of power.

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Sectionalizer
A SECTIONALIZER operates when a line is "dead" due to the operation of a reclosure or breaker along the line. Sectionalizers serve to isolate a section of line while allowing the remainder of the circuit to remain energized.

Service Drop
A SERVICE DROP is the lines running from a utility pole to a customer's house. Usually, a service drop is made up of two 120-volt lines and a neutral line, from which the customer can obtain either 120 or 240 volts of power. When these lines are insulated and twisted together, they are referred to as a triplex cable.

Short Circuit
A SHORT CIRCUIT is an interruption in the flow of electricity.

Single Phase Line
A SINGLE PHASE LINE carries electrical load capable of serving the needs of residential customers, small businesses and streetlights.

Substation
A SUBSTATION is a facility, generally a small building with a fenced-in yard containing switches, transformers and other equipment used to adjust voltages and monitor circuits.

System Peak
The SYSTEM PEAK is the maximum load on an electrical system during a given period of time.

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Three Phase Line
A THREE-PHASE LINE is a conductor capable of carrying heavy loads of electricity, usually to businesses.

Transformer
A TRANSFORMER is a device used to change the voltage levels of electricity to facilitate the transfer of electricity from generating stations to customers. A step-up transformer increases the voltage while a step-down transformer decreases it.

Transmission
TRANSMISSION is the transport of electricity at high voltages across long distances. The transmission system carries power from generating stations to various substations where it is transferred to a distribution system.

Transmission Lines
TRANSMISSION LINES are heavy wires that carry large amounts of electricity over long distances from generating stations to substations. Transmission lines are held high above the ground on tall structures called transmission towers.

Trip-Out
A TRIP-OUT is a disconnection of an electric circuit. When a line "trips-out," the circuit breaker has opened and the line is no longer able to carry electricity.

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Underground
UNDERGROUND refers to electrical facilities installed below ground level.

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Vault Transformer
A VAULT TRANSFORMER is similar to a pad-mounted transformer except that it is installed underground or inside a building.

Volt
A VOLT is a unit of electrical pressure measuring the force or push of electricity.

Voltage
VOLTAGE is what pushes current through wires.

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Watt
A WATT is the measure of work that electricity can do. Watts are commonly used to rate appliances.

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