Electrical Multiple Choice, CM 2112 ELECTRICITY VOCAB, CM 2112 ELECTRICAL T/F, Electrical Images CM 2112

Non-Metallic Sheathed Wires

2-3 conductor wire used for instrumentation.

Unistrut

A brand name of construction strut channel.

Flexible Metallic Conduit (FMC)

A flexible raceway of circular cross section for pulling electric cables through.

Galvanized Rigid Conduit (GRC)

A galvanized steel tubing, with a tubing wall that is thick enough to allow it to be threaded

Motor Controls

A group of devices that govern the performance of an electric motor in a predefined manner (e.g., starting/stopping the motor, regulating rotation speed).

Liquidtight Flexible Metallic Conduit (LFMC)

A metallic flexible conduit covered by a waterproof plastic coating.

Electrical Wire

A single electrical conductor

Rigid Metal Conduit (RMC)

A thick walled threaded tubing, usually made of coated steel, stainless steel, or aluminum

Electrical Nonmetallic Tubing (ENT)

A thin-walled corrugated tubing that is moistureresistant and flame retardant.

Electrical Metallic Tubing (EMT)

A thin-walled metal raceway having a circular cross section; used to pull in or withdraw electrical cables or wires after the tubing is installed in place; uses connectors and couplings other than the threaded type

Aluminum Conduits

A type of rigid conduit generally used in commercial and industrial applications where a higher resistance to corrosion is needed

Twinaxial Cable

A variant of coaxial cables, which features two inner conductors instead of one and is used for very-short-range high-speed signals.

High Voltage Circuit Breakers

According to the IEC, circuit breakers for controlling highpower transmission lines are rated for 72.5 KV and higher

Metallic Sheathed Cable

Also known as armored or BX cables, they are often used to supply mains electricity or for large appliances. They feature more than one conductor, each of which is insulated individually.

Triplex Wires

An electrical cable composed of two insulated aluminum wires wrapped with a third bare wire which is used as a common neutral.

Circuit breakers

Automatically operating safety switches which operate by measuring heat or current flowing through the circuit.

Electrical Enclosures

Boxes or cabinets which are used to contain electrical components like knobs, switches, controls and the like, to protect them from the environments, as well as safeguard property and life.

Air circuit breaker

Circuit breaker that can be used for low-voltage and some medium-voltage circuits too. Being classified into two types - plain air and air blast.

Magnetic Circuit Breaker

Circuit breaker that relies on electromagnetic energy created by electricity to trip a switch and disconnect power supply.

Thermal circuit breaker

Circuit breaker that uses heat as a measure of current flowing through a circuit and disconnect once it reaches beyond a certain temperature.

Oil-Based Circuit Breaker

Circuit breaker where both the contacts are submerged in insulating mineral oil.

Medium Voltage (MV) Circuit Breakers

Circuit breakers rated between 1 and 72 KV.

Hybrid Circuit Breaker

Circuit breakers that combine both magnetic and thermal circuit breakers, they combine the advantages of both.

Low Voltage Circuit Breakers

Circuit breakers used when the maximum voltage is about 1000Vac, and include miniature circuit breakers (MCB).

Cable Color Code

Color coding of cable insulation is done to determine active, neutral and earth conductors.

Coupling

Conduit fitting used to securely link together lengths of conduit and attaching site fabricated bends.

Unions

Conduit fitting with two separate heads and a locking mechanism which can connect two pieces of conduit together, even if they can't be physically turned.

Bends

Conduit fittings commonly called 'factory bends' or 'elbows'.

Nipples

Conduit fittings that do not exceed 24 inches in length, these are threaded on both ends and can be installed quickly and easily. Used for short runs or between nearby enclosures.

Locknuts

Conduit fittings threaded on the inside, with teeth on one surface or both, which grip the surface. Installed on both sides of an opening to ensure that both the conduit and bushing are held firmly in place.

Bushings

Conduit fittings used to create a smooth entry point to conduits without any sharp edges, protecting the conductors from damage during wire pulls. Installed on the inside of the box opening and threaded into the conduit end, separating the conductors from the edges of both the opening and the conduit end.

Drains

Conduit fittings used to prevent drips and water-logging in the conduit runs, especially in areas where the temperature varies significantly, or the conduit runs from a warm area to a cooler one, and moisture in the air starts condensing.

Weather head

Connection point on building that is used to electrically connect the building to the utility.

Electrical connectors

Connectors used to join electrical circuits (wires and cables) to form a continuous path for electrical current to flow.

Unshielded Twisted Pair Cable

Consist of two wires that are twisted together.

NEMA Standards 250-2003

Define hazardous location codes based on both the cause and the nature of the hazardous environment.

Panel Feed Wires

Electric wires used to power the main junction box and the circuit breaker panels. Should be rated for 25% more than the actual load.

Raceway

Enclosed conduit that forms a physical pathway for electrical wiring.

Hubs

Fitting used to connect conduits to bus boxes or enclosures that don't have a factory threaded entry.

Conduit Fittings

Fittings used for connecting runs of conduit together, and for connecting conduit ends to boxes, enclosures or electrical devices.

Grounding Lugs

Heavy duty lugs that are used for wires on transformers or steel structures.

Lugs

Heavy duty rings made from high grade electrolytic copper and are available in sizes ranging from #8AWG to 4/0AWG in a wide range of mounting holes. They have tin plating that provides resistance against corrosion and the terminals are CSA and UL listed.

Explosive Proof

In places where the spark or heat from electrical equipment can cause an explosion or start a fire, the components are housed in purpose-built electrical enclosures.

IEC

International Electrotechnical Commission.

Non-Metallic Sheathed Cable

Known as non-metallic building wire or NM cables. They feature a flexible plastic jacket with two to four wires and a bare wire for grounding.

Main Feeder Wires

Main power feeder wires are the wires that connect the service weather head to the building. Should be rated for 25% more than the actual load.

Electrical Conduit

Metal, plastic or fiber pipes designed to protect electrical cables and wires

NEMA

National Electrical Manufacturers Association.

Ribbon cables

Often used in computers and peripherals, with various conducting wires that run parallel to each other on a flat plane, leading to a visual resemblance to flat ribbons.

Liquidtight Flexible Nonmetallic Conduit (LFNC-B):

Refers to several types of flame resistant non-metallic tubing. Interior surfaces may be smooth or corrugated. There may be integral reinforcement within the conduit wall.

Underground Feeder Cable

Similar to NM cables, but wires are grouped together and embedded in the flexible material. They feature three plain stranded copper wires (one wire for the current, one grounding wire and one neutral wire) that are insulated with cross-linked polyethylene, PVC bedding and a black PVC sheathing.

Twisted Pair

Similar to paired cables, but the inner insulated wires are twisted or intertwined.

Reducers

Special combination coupling that allows connection of raceways of one trade size to larger or smaller ones.

Direct-Buried Cable (DBC)

Specially-designed coaxial or bundled fiber-optic cables, which do not require any added sheathing, insulation or piping before being buried underground. They feature a heavy metal core with many layers of banded metal sheathing, heavy rubber coverings, shock-absorbing gel and waterproof wrapped thread-fortified tape.

Compression Lugs

Stud-type input power connections that are generally made of high conduction wrought copper or aluminum

Wire lettering: T H HH W N X

T (wire lettering): Thermoplastic insulation H (wire lettering): Heat resistance HH (wire lettering): High heat resistance (up to 194°F) W (wire lettering): Suitable for wet locations N (wire lettering): Nylon coating, resistant to damage by oil or gas X (wire lettering): Synthetic polymer that is flame-resistant

NEC

The National Electrical Code, which regulates the manner of installation and the types of wires and cables for various electrical applications.

Ampacity

The amount of electric current that can flow through a wire.

External casing

The external shell of a circuit breaker that encases the other parts.

Cable size

The gauge of individual wires within the cable, such as 14, 12, 10 etc. (the bigger the number, the smaller the size).

Wire Lettering

The letters THHN, THWN, THW and XHHN represent the main insulation types of individual wires.

Polyvinyl Chloride Conduits (PVC)

The lightest in weight compared to other conduit materials, and usually lower in cost than other forms of conduit.

Wattage

The load a wire can take

Terminals

The pins in a connector which provide electrical conduction to make the connections

Wire gauge

The size of the wire.

Housing

The structure or case used to contain the terminals, ensure stability of the connections, and protect the electrical contacts from short-circuiting and environmental hazards.

Coaxial Cable

The two inner shields share the same geometric axis. They feature a tubular insulating layer that protects an inner conductor which is further surrounded by a tubular conducting shield, and might also feature an outer sheath for extra insulation

Twin-Lead Cable

These are flat two-wire cables that are used for transmission between an antenna and receiver, like TV and radio.

Reducing washers

Threaded reducers, similar to hubs, except both the inner and outer surfaces are threaded. Used to connect conduits to enclosure or box openings that have a larger diameter with locknuts on both sides to fasten them in place.

Clamps

To fasten conduit runs to fixed structures, like beams, hangers or unistrut channels.

Conduit Bodies

Tubular units with openings at each end for admitting conduits, and providing access to the wires.

Electrical Cable

Two or more wires running side by side and bonded, twisted, or braided together to form a single assembly, the ends of which can be connected to two devices, enabling the transfer of electrical signals from one device to the other.

Mechanical Lugs

Typically ring-shaped power connections with two screws or with four screws usually made of high-grade electrolyte copper or aluminum.

Straps

Used to mount the conduit to ceilings or walls using a screws or bolts.

d. Reducers

What allows you to connect raceways of one trade size to larger or smaller ones and is also handy for areas that have limited spaces? a. Nipples b. Couplings c. Bends d. Reducers

d. Nipples

What can save time and money when a conduit is needed in certain situations, but as per the NEC, it cannot exceed 24 inches? a. Reducing Washers b. Straps c. Reducers d. Nipples

b. Liquidtight Flexible Nonmetallic Conduit

What conduit is not suitable for housing conductors carrying over 600 volts? a. Polyvinyl Chloride Conduits b. Liquidtight Flexible Nonmetallic Conduit c. Electrical Nonmetallic Tubing d. Flexible Metallic Conduit

a. Flexible Metallic Conduit

What conduits absorb vibrations and allow movement, but cannot be used outdoors, buried, or embedded? a. Flexible Metallic Conduit b. Electrical Nonmetallic Tubing c. Electrical Metallic Tubing d. Liquidtight Flexible Nonmetallic Tubing

a. Aluminum Conduits

What conduits are common in commercial applications and resist corrosion very well? Select one: a. Aluminum Conduits b. Electrical Metallic Tubing c. Liquidtight Flexible Nonmetallic Conduit d. Flexible Metallic Conduit

d. Polyvinyl Chloride Conduits

What conduits are flame retardant, resistant to sunlight, and very affordable, but cannot be used in hazardous locations? a. Electrical Nonmetallic Tubing b. Electrical Metallic Tubing c. Liquidtight Flexible Nonmetallic Conduit d. Ployvinyl Chloride Conduits

b. Electrical Metallic Tubing

What conduits are the absolute most used, while not technically being conduits at all? a. Electrical Nonmetallic Tubing b. Electrical Metallic Tubing c. Flexible Metallic Conduit d. Liquidtight Flexible Nonmetallic Conduit

b. Electrical Nonmetallic Tubing

What conduits have pliable corrugated raceways made from non-metallic material that is resistant to chemicals, moisture and flames? Select one: a. Polyvinyl Chloride Conduits b. Electrical Nonmetallic Tubing c. Liquidtight Flexible Nonmetallic Conduit d. Flexible Metallic Conduit

d. Rigid Metal Conduit

What conduits have the toughest and thickest walls made from coated stainless steel and aluminum? a. Electrical Nonmetallic Tubing b. Electrical Metallic Tubing c. Liquidtight Flexible Nonmetallic Conduit d. Rigid Metal Conduit

c. Unions

What connects sections of a conduit to ensure that they are locked and installed properly, while being available in different configurations with male and female heads, or a combination of both? a. Reducing Washers b. Bends c. Unions d. Couplings

d. Bushings

What creates a smooth entry point to conduits without any sharp edges, protecting the conductors form damage during wire pulls? a. Conduit Bodies b. Reducing Washers c. Couplings d. Bushings

d. Clamps

What fastens objects together to prevent movement of separation while coming in various types for different uses? a. Reducing Washers b. Conduit Bodies c. Straps d. Clamps

c. Conduit Bodies

What has a variety of designs while being able to join two different types or sizes of conduits? a. Reducing Washers b. Bends c. Conduit Bodies d. Reducers

a. Locknuts

What is installed to ensure that both the conduit and bushing are held firmly in place? a. Locknuts b. Couplings c. Bends d. Straps

b. Triplex Wires

What is used mostly in single-phased service drop conductors, between the power pole and weather heads with two insulated aluminum wires wrapped with a third bare wire. a. Panel Feed Wires b. Triplex Wires c. Non-Metallic Sheathed Wires d. Main Feeder Wires

a. Hubs

What is used to connect conduits to bus boxes or enclosures that don't have a factory- threaded entry? a. Hubs b. Bends c. Conduit Bodies d. Straps

c. Reducing Washers

What is used to connect conduits to enclosure or box openings that have a large diameter and has threaded inner and outer surfaces? a. Reducers b. Hubs c. Reducing Washers d. Straps

a. Straps

What is used to mount the conduit to ceilings or walls using a screw or bolts? a. Straps b. Reducing Washers c. Couplings d. Nipples

d. Couplings

What links together lengths of conduits and attaches site-fabricated bends? a. Bends b. Reducers c. Conduit Bodies d. Couplings

d. Drains

What prevents drips and water-logging in conduit runs? a. Reducers b. Conduit Bodies c. Bends d. Drains

a. Bends

What saves time, equipment, and labor costs while coming in a variety of lengths and curvatures? a. Bends b. Straps c. Conduit Bodies d. Couplings

a. FlexibleMetallic Conduit

What type of conduit is also known as "Greenfield" Conduit? a. Flexible Metallic Conduit b. Electrical Nonmetallic Tubing c. Rigid Metal Conduit d. Liquidtight Flexible Nonmetallic Conduit

c. Non-Metallic Sheathed Wires

What wires are used in most homes and have 2-3 conductors, each with plastic insulation, and a bare ground wire, and are covered with another layer of a bare ground wire. a. Single Strand Wires b. Panel Feed Wires c. Non-Metallic Sheathed Wires d. Triplex Wires

d. Panel Feed Wires

What wires are used to power the main junction box and the circuit breaker panels? a. Non-Metallic Sheathed Wires b. Triplex Wires c. Single Strand Wires d. Panel Feed Wires

c. Main Feeder Wires

What wires connect the service weather head to the house and are made with stranded or solid THHN wire? a. Panel Feed Wires b. Triplex Wires c. Main Feeder Wires d. Single Strand Wires

Paired Cable

With two individually insulated conductors, this cable is normally used in DC or low-frequency AC applications.