Module 2: Electrical Conductors and Insulators

Building Utilities 2

Conductors

Substances with high conductivity, which have very

mobile electrons

examples of conductors

copper, silver, gold

conductors

materials that allow flow of an electric current

Bare Conductor

a conductor

having no covering or insulation.

Covered Conductor

encased within a material of composition and thickness not recognized by

code.

Insulated Conductor

encased within a material of composition and thickness recognized by code.

insulators

Substances with low conductivity; prevent flow of electrons

Class A

(1) Cotton, silk, paper and materials of paper

(2) Molded laminated materials with cellulose filler
(3) Films/sheets of cellulose acetate
(4) Varnishes or enamel

Class B

Consists of mica, asbestos, or fiberglass; all with a

binder.

Class C

Consists entirely of mica, porcelain, glass, quartz, or

similar materials.

Class O

Consists of cotton, silk, paper, or similar materials that are not impregnated or immersed in an

insulating liquid.

wires

are electrical conductors which are 8 mm2 (No. 8 AWG) or smaller

cables

larger than wires

wires

single conductor number 14 AWG, 12

AWG, 10 AWG, and 8 AWG

AWG or American Wire Gauge

indicates the size of the wire

Solid Wire

Also known as solid-core or single-strand wire, consists

of a one piece of wire on its entire cross section.

Stranded Wire

Consists of a group of wires twisted to form metallic string.

Cord

Refers to insulated wire that is flexible.

cables

electrical conductors larger than wires. A

single Number 6 AWG to 0000 AWG

stranded cables

cables with sizes from Number 6 AWG and larger

1/0 AWG

0 AWG is equivalent to

2/0 AWG

00 AWG is equivalent to

3/0 AWG

000 AWG is equivalent to

4/0

0000 AWG is equivalent to

Bus, Busbar

A rigid electric conductor, usually a metal bar, hollow tube, or rod, which forms a connection between electric circuits.

properties of copper

Ductile,

malleable, and an excellent

conductor of heat and energy.

copper

Harder than zinc and softer than

iron. Approximately 50% of its

total output is used for

manufacturing electrical apparatuses and

conductors.

aluminum

produced by

the formation of many

metals, such as feldspar,

mica, alum, cryolite, clay,

bauxite

Circular Mil (CM)

Unit of measuring cross-section size in American Wire

Gauge (AWG).

mil

means one-thousandth of

an inch (0.001 in.).

Square Mil

The area of a square having its side equal to 1 mil.

(diameter in mils)^2

Area in CM

(mils)^2

CM

1000 mils

1 inch

1/1000 in

1 mil