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Section 2 Installation
All persons involved in the electrical trade
should become familiar with the OSHA elec-
trical standards, which specifi cally address the
following areas:
• Hazardous locations
• Wiring methods, components and equipment
• Special systems
• Specifi c purpose equipment
• Wiring design and protection
• Electric utilization systems
• Defi nitions
• General requirements
Wiring Systems
Conductors for carrying electricity are
commonly called wiring. A wiring system
includes the wire, its insulating cover, a protec-
tive cover, and connectors that fasten it to an
electrical box. See Figure 4-4. In some systems,
the protective covering and the wire are
purchased separately and the electrician assem-
bles them on the job. In other cases, the protec-
tive covering is installed during manufacture.
Depending on the structure being wired,
several different systems may be used.
Regardless of the wiring system, it is impor-
tant to have a continuous ground throughout
every part of the system and every circuit.
Refer to Chapter 9, Grounding of this text for
grounding requirements. All of these systems
are adequate for most installations. Some cannot
be used where there are unusual hazards such
as extreme moisture, explosive gases, or corro-
sive chemicals.
The wiring system selected depends on:
• Type of dwelling (style)
• Materials and type of construction used
(such as log, concrete, post and beam, or
platform)
Figure 4-3. Engineers test electrical appliances
and equipment to ensure that the products are safe.
(Underwriters Laboratories, Inc.)
History Brief
OSHA
Congress created OSHA under the
Occupational Safety and Health Act, which
was signed by President Richard M. Nixon.
Since its inception in 1971, OSHA has helped
to cut workplace fatalities by more than 60
percent and occupational injury and illness
rates by 40 percent.
wiring: The wires installed in a building that provide
the electrical power throughout.
wiring system: In residential construction, the mate-
rials and components used to deliver electricity from
the service panel to electrical devices. The wiring
system includes the wire, its insulating cover, a protec-
tive cover, and the connectors that fasten it to an elec-
trical box.