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Glossary
[A]
Acid Rain:
Rain that has become acidic due to the
emission of sulfur dioxide and nitrogen
oxides.
Active
Power:
See Real Power.
Air
Leakage Rating:
The air leakage rating is a measure of how
much air leaks through the crack between the
window sash and frame. The rating reflects
the leakage from a window exposed to a
25-mile-per-hour wind, and is measured in
cubic feet per minute per linear foot of
sash crack.
Alternating
Current (AC):
Electric current which changes direction
with a regular frequency. Domestic mains in
the UK have a frequency of 50 Hertz.
Alternator:
An electric generator designed to produce
alternating current. Usually consists of
rotating parts which created the changing
magnetic field to produce the alternating
current.
Ambient
Temperature:
The surrounding temperature of an area.
American
Wire Gauge:
A standard measure which represents the size
of wire. The larger the number, the smaller
the wire. Abbreviated AWG.
Ampacity:
The current, in amperes, that a conductor
can carry continuously under the conditions
of use without exceeding its temperature
rating.
Ampere:
A type of electric current produced by one
volt applied across a resistance of one ohm.
It is also equal to the flow of one coulomb
per second. Named after French physicist
Andre M. Ampère 1836.
Analog:
A measuring or display methodology which
uses continuously varying physical
parameters. In contrast, digital represents
information in discrete binary form using
only zeros and ones.
Annual
Fuel Utilization Efficiency (AFUE):
An indication of how well a furnace converts
energy into usable heat. The rating is
expressed as a percentage of the annual
output of heat to the annual energy input to
the furnace.
Appliance:
Utilization equipment, generally other than
industrial, normally built in standardized
sizes or types, that is installed or
connected as a unit to perform one or more
functions such as clothes washing, air
conditioning, food mixing, deep frying, etc.
[B]
Battery:
A group of two or more cells connected
together to provide electrical current.
Sometimes also used to describe a single
cell which converts chemical energy to
electrical current.
Blower
Doors:
Energy contractors use blower doors to see
how much air leaks through windows, doors,
and other places in your house. The blower
door is a large board that blocks the front
door of your house. A powerful fan installed
in the door draws the air out of your house
and causes a strong draft inside where ever
the air is leaking in. This can help the
contractor locate the air leaks, and gives a
good overall indication of how "leaky" your
house is.
Branch
Circuit:
The circuit conductors between the final
overcurrent device protecting the circuit
and the outlet(s).
Branch Circuit, Appliance:
A branch circuit that supplies energy to one
or more outlets to which appliances are to
be connected, and that has no permanently
connected lightning fixtures that are not a
part of an appliance.
Brownout:
A reduction in voltage and/or power when
demand for electricity exceeds generating
capacity. The term brownout is misleading
because customers generally do not notice
the reduction, except when it affects
sensitive electronic equipment.
BTU
(British Thermal Unit):
A BTU is the standard unit for measuring the
quantity of heat energy such as the heat
content of fuel. It is the amount of heat
energy necessary to raise the temperature of
one pound of water one degree Fahrenheit
(3412 BTU's=1 kWh).
Building:
A structure that stands alone or that is cut
off from adjoining structures by fire walls
with all openings therein protected by
approves fire doors.
[C]
Cabinet:
An enclosure designed either for surface
mounting or flush mounting and is provided
with a frame, mat, or trim in which a
swinging door or doors are or can be hung.
Capacitor:
A device that stores electrical charge
usually by means conducting plates or foil
separated by a thin insulating layer of
dielectric material. The effectiveness of
the device, or its capacitance, is measured
in Farads.
Cell:
a single device which converts chemical
energy into electrical current. Sometimes
also referred to as a battery.
Circuit
Breaker:
A device designed to open and close a
circuit by non-automatic means and to open
the circuit automatically on a
pre-determined overcurrent without damage to
itself when properly applied within its
rating.
Circuit
Extensions:
To extend or add-on to an existing circuit
to provide an additional power source.
Code
Corrections:
Procedure designed to eliminate wiring
conditions that do not meet National
Electrical Code requirements and safety
conditions.
Cold-Weather
Ballast:
Compact fluorescent light bulbs require a
ballast to regulate the voltage of the
electricity that is applied to the gas
inside the lamp. Below-freezing weather can
adversely affect the electronic components
in these ballasts, causing most compact
fluorescent bulbs to appear dim in cold
weather. Cold-weather ballasts compensate
for this problem and keep the bulb glowing
brightly, even in weather as cold as -10°F
(-23°C).
Conductor:
Bare
- A conductor having no covering or
electrical insulation whatsoever.
Covered - A conductor encased within
material of composition and thickness that
is NOT recognized by this Code as
electrical insulation.
Insulated - A conductor encased
within material of composition and thickness
that is recognized by this Code as
electrical insulation.
Continuous
Load:
A load where the maximum current is expected
to continue for 3 hours or more.
Controller:
A device or group of devices that serves to
govern, in some predetermined manner, the
electric power delivered to the apparatus to
which it is connected.
Current:
The flow of electricity commonly measured in
amperes.
[D]
Decibel:
A logarithmic measure of the ratio of two
quantities. Abbreviated dB. For electrical
power, 1 dB = 10 x log10 P1/P2.
For electric voltage or current, 1 dB = 20 x
log10 E1/E2.
Device:
A unit of an electrical system that is
intended to carry but not utilize electric
energy.
Diode:
An electronic semiconductor device that
predominantly allows current to flow in only
one direction.
Direct
Current (DC):
Circuit in which the flow of electrons is in
one direction only, from anode to cathode.
Distribution
Equipment:
A device designed to provide electricity to
multiple connections.
Dwelling:
One or more rooms for the use of one or more
persons as a housekeeping unit with space
for eating, living, and sleeping, and
permanent provisions for cooking and
sanitation.
[E]
Electric Resistance Heating:
A type of heating system that generates heat
by passing current through a conductor,
causing it to heat up. These systems usually
use baseboard heaters, often with individual
controls. They are inefficient and are best
used as a backup to more efficient options,
such as solar heating or a heat pump.
Electronic
Ballasts:
An electronic device that regulates the
voltage of fluorescent lamps. Compared to
older magnetic ballasts, electronic ballasts
use less electricity and are not prone to
the flickering and humming effects sometimes
associated with magnetic ballasts.
Energy
Saving Devices:
Devices utilized within a dwelling designed
to more efficiently make use of energy
sources while providing heating, cooling,
and light.
Enclosure:
The case or housing of an apparatus, fence,
or walls that prevent persons from
accidentally contacting energizing parts, or
to protect the equipment from physical
damage.
Energizing:
Electrically connected to a source of
potential difference.
Energy:
The capacity for, or the ability to do,
mechanical work. Electrical energy is
measured in kilowatt-hours for billing
purposes.
Energy
Efficiency Ratio (EER):
The ratio of the cooling capacity of the air
conditioner, in
Btu per hour, to the total electrical
input in watts under test conditions
specified by the
Air-Conditioning and Refrigeration
Institute.
Energy
Saving Devices:
Devices utilized within a dwelling designed
to more efficiently make use of energy
sources while providing heating, cooling,
and light.
Equipment:
A general term including materials,
fittings, devices, appliances, fixtures,
apparatus, and the like used as a part of,
or in connection with, an electrical
installation.
[F]
Fault:
A short circuit in an electrical system.
Fitting:
An accessory such as a locknut, bushing, or
other part of a wiring system that is
intended primarily to perform a mechanical
rather than an electrical function.
Fluorescent
Lamps:
Fluorescent lamps produce light by passing
electricity through a gas, causing it to
glow. The gas produces ultraviolet light; a
phosphor coating on the inside of the lamp
absorbs the ultraviolet light and produces
visible light. Fluorescent lamps produce
much less heat than
incandescent
lamps and are more energy efficient.
Linear fluorescent lamps are used in long
narrow fixtures designed for such lamps.
Compact fluorescent light bulbs have been
designed to replace incandescent light bulbs
in table lamps, floodlights, and other
fixtures.
Frequency:
In alternating current, the rate at which
the current changes direction. One complete
cycle is a unit of 1 Hertz, named after the
Physicist who researched AC
(Alternating Current). The standard
frequency in the US is 60 Hz.
[G]
Garage:
A building or portion of a building which
one or more self-propelled vehicles carrying
volatile flammable liquid for fuel or power
are kept for use, sale, storage, rental,
repair, exhibition, or demonstration
purposes.
Generator:
A rotating machine which converts mechanical
energy into electrical energy. In the
automotive industry traditional terminology
uses generator to refer to only those
machines designed to produce dc current
through brushes and a commutator (as opposed
to alternator).
Global
Warming:
Global warming is the gradual increase in
global temperatures caused by the emission
of gases that trap the sun's heat in the
Earth's atmosphere. Gases that contribute to
global warming include carbon dioxide,
methane, nitrous oxides, (CFC's)
chlorofluorocarbons, and halocarbons (the
replacements for CFC's). The carbon dioxide
emissions are primarily caused by the use of
fossil fuels for energy.
Grid:
In an electrical system, a term used to
refer to the electrical utility distribution
network.
Ground
(Wire):
A conducting connection, whether intentional
or accidental, between an electrical circuit
or equipment and the earth, or to some
conducting body that serves in place of the
earth.
Grounded:
Connected to earth or to some conducting
body that serves in place of the earth.
[H]
Heater:
A heat source (gas or electric) used to
adjust the temperature inside a dwelling
from a cold to a warm condition.
Heavy
Duty:
A lightning impulse classifying current
category for distribution class arresters
defined by ANSI/IEEE C62.11. A heavy duty
rated arrester has a 10,000 amperage impulse
value crest (refer to
normal duty).
Hertz
(Hz):
The unit of frequency (not just electricity,
but also, for example, sound waves.
High-Tech
Troubleshooting:
A procedure performed by a trained
technician for the purpose of locating and
identifying electrical problems within an
electrical system.
Hoistway:
Any shaftway, hatchway, well hole, or other
vertical opening or space in which an
elevator or dumbwaiter is designed to
operate.
Horsepower:
A unit of power equal to 746 watts.
[I]
Impedance:
The total effects of a circuit that oppose
the flow of an AC current consisting of
inductance, capacitance, and resistance. It
can be quantified in the units of ohms.
Impulse:
A current surge.
Incandescent
Light Bulbs:
Incandescent light bulbs produce light by
passing electricity through a thin filament,
which becomes hot and glows brightly.
Incandescent light bulbs are less
energy-efficient than
fluorescent lamps,
because much of the electrical energy is
converted to heat instead of light. The heat
produced by these bulbs not only wastes
energy, but can also make a building's air
conditioning system work harder and consume
more energy.
Infrared
Cameras:
Energy contractors use infrared cameras to
look at the heat leaking into or out of your
house. The infrared camera "sees" the heat
and can show "hot spots" where a lot of heat
is being lost. This helps to identify the
places where your home's energy efficiency
can be improved.
Insulation:
A material having a high resistance to the
flow of electric current; insulation over
underground conductor is made of either EPR
or XLPE material.
Insulator:
Any material which does not allow electrons
to flow through it.
Interrupter:
An element designed to interrupt specific
currents under specified conditions.
Inverter:
An electrical device which is designed to
convert direct current into alternating
current. This was originally done with
rotating machines which produced true sine
wave ac output. More recently this
conversion has been performed more
economically and efficiently using solid
state electronics. However, except for the
most expensive models, these devices usually
do not produce perfect sine wave output.
This sometimes can result in electromagnetic
interference with other sensitive electronic
devices.
Ion:
An Ion is a positively or negatively charged
atom or molecule.
[J]
Joule:
A unit of work or energy equal to one watt
for one second. One kilowatt hour equals
3,600,000 Joules. Named after James P.
Joule, an English physicist 1889.
Joule’s
Law:
Defines the relationship between current in
a wire and the thermal energy produced. In
1841an English physicist James P. Joule
experimentally showed that W = I2
x R x t where I is the current in the wire
in amperes, R is the resistance of the wire
in Ohms, t is the length of time that the
current flows in seconds, and W is the
energy produced in Joules.
[K]
Kilovolt:
A Unit of electrical potential equal to
1,000 volts. Abbreviated kV or KV.
Kilowatt
(kW):
Real power delivered to a load (W x 1,000
VA).
Kilowatt-hour:
A unit of energy or work equal to one
kilowatt for one hour. Abbreviated as kwh or
KWH. This is the normal quantity used for
metering and billing electricity customers.
The price for a kwh varies from
approximately 4 cents to 15 cents. At a 100%
conversion efficiency, one kwh is equivalent
to about 4 fluid ounces of gasoline, 3/16
pound LP, 3 cubic feet natural gas, or 1/4
pound coal.
[L]
Limit Switch:
A switch that is operated by some part or
motion of a power-driven machine or
equipment to alter the electric circuit
associated with the machine or equipment.
Liquid-Filled
Transformer:
A transformer in which the core and coil are
immersed in a liquid which acts as both a
cooling and insulating medium.
Live
Parts:
Electric conductors, buses, terminals, or
components that are uninsulated or exposed
and an electric shock hazard exists.
Load:
The load of a transformer is the power, in
kVA or volt-amperes, supplied by the
transformer.
(Lagging Load) inductive type load.
(Leading Load) capacitive load.
Loadbreak:
The ability of a switching device to
disconnect a load current without damage.
Load
Center:
Source for all power to the home. All
circuits originate from the "Load Center" or
"Service Panel." Circuit breakers are
located within this panel.
Load
Curve:
A curve showing instantaneous demand (kVA or
MVA) versus time. Curves are usually plotted
for one day or one week. Integrating the
load curve will provide the amount of energy
consumed.
Load
Factor:
Represents how efficiently the electrical
system capacity is being used. The higher
the load factor the higher the efficiency.
Load
Switching:
Transferring the load from one source to
another.
Low
Voltage:
A wiring system that provides power to some
electronic devices operating on a voltage
level much lower than the standard 110
volts. Such devices might be doorbells and
thermostats.
[M]
Metal Enclosed:
Surrounded by a metal case of housing,
usually grounded.
Metalclad:
Devices in which the conducting parts are
entirely enclosed in a metal casing.
Motors:
Electronic device used to move, switch, or
adjust one or more of the systems within a
dwelling.
[N]
National Electrical Code (NEC):
A code/guideline used for the safeguarding
of people and property from hazards related
to the use of electricity. Compliance with
this code along with proper maintenance will
result in an installation essentially free
from hazard. Abbreviated NEC. The NEC was
first developed in 1897 as a result of the
efforts of various insurance, electrical,
architectural, and allied interests. It is
sponsored and regularly updated by the
National Fire Protection Association.
Neutral:
The junction point of the legs in a Wye
circuit.
Neutral
Grounding Resistor:
A grounding device, the principal element of
which is resistance, which is used to
connect the neutral point of the transformer
to earth.
Normal
Duty:
A lightning impulse classifying current
category for distribution class arresters
defined by ANSI/IEEE C62.11. A normal duty
rated arrester has 5000 amperage impulse
value crest (refer to
heavy duty).
[O]
Ohm:
The unit of measure for resistance.
Outlet:
A point on the wiring system at which
current is taken to supply utilization
equipment.
Overload:
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.
Overvoltage:
A voltage above the normal rated voltage or
the maximum operating voltage of a device or
circuit. A direct test overvoltage is a
voltage above the peak of the line
alternating voltage.
[P]
Peak Demand:
The maximum integrated demand during a time
period.
Phase:
Classification of an AC circuit usually
single-phase, two wire or three wire;
two-phase, three wire or four wire; or
three-phase, three wire or four wire.
Power:
The rate at which work is performed or that
energy is transferred. Electric power is
commonly measured in watts or kilowatts. A
power of 746 watts is equivalent to 1
horsepower.
Power
Outage:
An interruption of power.
Power
Outlet:
An enclosed assembly that may include
receptacles, circuit breakers, fuseholders,
fused switches, buses, and watt-hour meter
mounting means; intended to supply and
control power to mobile homes, recreational
vehicles, park trailers, or boats; or to
serve as a means for distributing power
required to operate mobile or temporarily
installed equipment.
Primary
Voltage Rating:
Designates the input circuit voltage for
which the primary winding is designed.
Puncture:
Term used when a disruptive discharge occurs
through a solid dielectric. A disruptive
discharge in a solid dielectric produces a
permanent loss of dielectric strength; in a
liquid of gaseous dielectric, the loss may
be only temporary.
[Q]
Qualified Person:
One familiar with the construction and
operation of the equipment and the hazards
involved.
[R]
Rainproof:
Constructed, protected, or treated so as to
prevent rain from interfering with the
successful operation of the apparatus under
specified test conditions.
Rating:
The rating of an arrester - either duty
cycle or MCOV rating.
Reactive
Power:
The mathematical product of voltage and
current consumed by reactive loads. Examples
of reactive loads include capacitors and
inductors. These types of loads when
connected to an ac voltage source will draw
current, but since the current is 90o
out of phase with the applied voltage they
actually consume no real power in the ideal
sense.
Reactor:
A device for introducing inductive reactance
into a circuit for motor starting, operating
transformers in parallel, and controlling
current.
Real
Power:
The rate at which work is performed or that
energy is transferred. Electric power is
commonly measured in watts or kilowatts. The
term real power is often used in place of
the term power alone to differentiate from
reactive power. Also called active power.
Receptacles:
Power sources located throughout a building
to provide electricity where needed.
Resistor:
Any device of material that limits the flow
of current when voltage is applied.
[S]
Service:
The conductors and equipment for delivering
electric energy from the serving utility to
the wiring system of the premises served.
Series
Gap:
Internal gap(s) between spaced electrodes in
series with the valve elements across which
all or part of the impressed arrester
terminal voltage appears.
Series/Multiple:
A winding of two similar coils that can be
connected for series operation or multiple
(parallel) operation.
Service
Cable:
Service conductors made up in the form of a
cable.
Smoke
And Carbon Dioxide Detectors:
Wall and ceiling mounted sensors located
throughout the home used to alert occupants
of deadly gasses and smoke inside the home.
Storm
Windows:
An extra pane of glass or plastic added to a
window to reduce air infiltration and boost
the insulation value of a window. If you are
considering adding storm windows, you should
compare the costs to installing new
energy-efficient windows.
Switchboard:
A large single panel, frame, or assembly of
panels on which are mounted, on the face or
back, or both, switches, overcurrent and
other protective devices, buses, and usually
instruments. Switchboards are generally
accessible from the rear as well as from the
front and are not intended to be installed
on cabinets.
Switches:
Circuit interruption devices used to control
the flow of electricity to lights,
appliances, and outlets.
Switch
Limit:
A switch that is operated by some part or
motion of a power-driven machine or
equipment to alter the electric circuit
associated with the machine or equipment.
Symmetric:
A term used to explain the normal, rhythmic
ac flow of current (transient or dc
component = ); the steady state component of
any current or fault current calculation.
Systems
Capacity:
Represents the ability of a system to meet
its customers' needs, or meet the electrical
demand of its customers. System capacity is
provided by generators, transmission lines,
distribution networks and load management.
[T]
Tap:
A connection brought out of the winding at
some point between its extremities, usually
to permit changing the voltage or current
ratio.
Thermostat:
A low voltage electronic switching device
that monitors temperatures inside the home
and turns on and off the heating or cooling
system in the home.
Track
And Accent Lighting:
Condition specific lighting that meets
special lighting requirements, providing
variable lighting degrees of light and may
distribute light in multiple directions.
Transfer
Switch:
An electronic device that under certain
conditions will disconnect from one power
source and connect to another power source.
Transformer:
A static electrical device which by
electromagnetic induction transfers
electrical energy from one circuit to
another circuit usually with changed values
of voltage and current in the process.
Transient:
A high amplitude, short duration pulse
superimposed on the normal voltage.
Turn
Ratio:
The ratio of the number of turns in the high
voltage winding to that in the low voltage
winding.
[U]
Uninterruptible Power Supply:
A device that provides a constant regulated
voltage output in spite of interruptions of
the normal power supply. It includes
filtering circuits and is usually used to
feed computers or related equipment which
would otherwise shutdown on brief power
interruptions. Abbreviated UPS.
Universal
Taps:
A combination of six primary voltage taps
consisting of four 2-1/2% FCBN and two
2-1/2: FCAN, covering 15% voltage range.
[V]
Vapor Barrier:
Also called a vapor retarder, this is a
material that retards the movement of water
vapor through a building element (such as
walls, floors, and ceilings) and prevents
metals from corroding and insulation and
structural wood from becoming damp.
Ventilated:
Provided with a means to permit circulation
of air sufficient to remove an excess of
heat, fumes, or vapors.
Volt:
The electrical potential difference or
pressure across a one ohm resistance
carrying a current of one ampere. Named
after Italian physicist Count Alessandro
Volta 1745-1827.
Volt
Ampere:
A unit of apparent power equal to the
mathematical product of a circuit voltage
and amperes. Here, apparent power is in
contrast to real power. On ac systems the
voltage and current will not be in phase if
reactive power is being transmitted. Usually
abbreviated VA.
[W]
Watertight:
Constructed so that moisture will not enter
the enclosure under specified test
conditions.
Waterproof:
Constructed or protected so that exposure to
the weather will not interfere with
successful operation.
Watt:
A unit of power equal to the rate of work
represented by a current of one ampere under
a pressure of one volt. Named after the
Scottish engineer James Watt, 1819.
Wiring:
A distribution network of wire that conducts
electricity to receptacles, switches and
appliances throughout a building/home to
provide electricity where needed.
Whole-House
Fan:
A large fan used to ventilate your entire
house. This is usually located in the
highest ceiling in the house, and vents to
the attic or the outside. Although
whole-house fans are a good way to draw hot
air from the house, you must be careful to
cover and insulate them during the winter,
when they often continue to draw hot air
from people's houses
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