ELECTRICAL TERMS AND DEFINITIONS

Amp (Ampere) A unit that measures strength/rate of flow of electrical

Armored Cable

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Electrical wires protected by a metal sheath

Branch Circuits

The circuits in a house running from the load center/service panel to boxes and devices

Breaker

A switch-like device that connects/disconnects power to a circuit.

Brownout

A reduction in power or voltage due to excessive demand

Buss Bar

Separate metallic strips that extend through the service panel. Breakers slide onto "hot" busses and the neutral and ground wires screw down in their respective busses.

Cable Clamps

Metal clips inside an electrical box that hold the wires in place

Circuit Breaker

A protective device that protects a circuit in case of an electrical power surge. A breaker trips when a circuit becomes overloaded or shorts out.

Conduit

A protective casing that wires run through

Duplex Receptacle

A plug outlet comprising two plug-in sockets

Fuses

A removable device that link a circuit a the fuse box. Fuse connections blow apart and break an electrical circuit if an overload or short occurs

Fixture

Any permanently connected electrical device that consumes power

GFCI or GFI
(Ground Fault Circuit Interrupter)

A specific type of circuit protection that helps to protect from electrical shocks

Ground

A conducting connection between an electrical circuit or equipment and the earth.

Ground Fault

A problem where current is misdirected from the hot (or neutral) lead to a ground wire, box or connector.

Hot, Neutral, Ground

The three most common circuit wires. The hot brings in the current flow, the neutral returns it to the source and the ground acts as a safety route for returning current. The ground and neutral are should be joined at the load center.

Horsepower

A unit of power equivalent to 746 watts.

Impedance

The total effects of inductance, capacitance and resistance in a circuit that oppose the flow of an AC current quantified in Ohms.

Kilowatt-hour

KWH. A unit of energy equal to one kilowatt for one hour.

Knockout

A removable piece of an electrical box or panel that is "knocked out" to allow a cable to enter the box.

Load Center

Source of 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. Usually plotted for one day or one week.

Load Factor

The efficiency of an electrical system.

Ohm

A unit of resistance in an electrical circuit or conductor.

Outlet

A point on the wiring system at which current is drawn to supply equipment

Peak Demand

The maximum combined demand over a time period.

Phase

The classification of an AC circuit; usually single phase (2-3 wire) and three phase (3-4 wire). Three phase circuits are typically used where higher power rating is required (i.e. large A/C units)

Short Circuit

A problem whereby current fails to reach a device caused by a hot conductor accidentally contacting a neutral or ground.

Transformer

A static electrical device which transfers electrical energy from one circuit to another using electromagnetic induction typically with a change in voltage and current.

Volt

A unit that measures the electrical "pressure" in a system.

Watt

A unit that measures the electrical power in a circuit