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Section 2 Installation
Copyright Goodheart-Willcox Co., Inc.
Armored Cable
Armored cable (AC) is a manufactured
assembly of insulated conductors in a fl exible
interlocked metallic armor, Figure 4-5. AC is
frequently called BX, a trade name for armored
cable produced at the Sprague Electric division
of General Electric.
The conductors in AC may be copper,
aluminum, or copper clad aluminum. The
outer covering is called armor and is made of
steel or aluminum. As always, see the manu-
facturer’s instructions before installing. One of
the conductors in the cable is an uninsulated
conductor that is in continuous contact with the
armor. This wire is called a bonding strip.
The use of AC is generally limited to dry
locations where it is not subject to physical
damage. Thus, it may be used in masonry block,
tile walls, attics, and wall spaces, as well as
along studs, rafters, and joists. Also, care must
be taken to maintain a bend radius of the AC
that is fi ve times its diameter.
Armored cable is expressly forbidden for
use in:
• Commercial garages.
• Hoistways, elevators, or cranes.
• Theaters or motion picture studios.
AC is quite fl exible and can be pulled
through bored holes with ease. The holes
should be slightly larger than the cable to avoid
strain during installation. AC can be measured
and cut before it is pulled through the holes in
the framing members. Measure the distance
along the route the cable will run and transfer
this measurement to the cable. Allow 6″ to 8″
extra at each end for making connections. Cut
the length of cable needed using a hacksaw, or
reciprocating saw, Figure 4-6.
Stripping armored cable
There are several methods for cutting through
the metal armor and stripping the cable end.
Regardless of the method used, always be careful
to not damage the wires inside the armor.
• Hacksaw. The most common tool for cutting
the armor is the hacksaw. The hacksaw blade
is placed on the armor so that it makes a diag-
onal cut across one of the high ridges. See
Figure 4-7. Once the armor is cuta through, it
can be twisted off the inside wires.
armored cable (AC): An assembly of insulated
wires contained within a fl exible metallic armor for
protection.
BX: Another name for armored cable (AC). BX is a
trade name attributed to the Sprague Electric division
of General Electric.
Anti-short
bushing
White wire covered
with paper
Bonding
strip
Black
wire
Paper
Armor
Figure 4-5. These are the components that make up armored cable.
armor: The metallic spiral tubing that protects the con-
ductors in armored cable.
bonding strip: A piece of wire manufactured into AC
that runs the length of the armor and is in constant
contact with it. It provides the continuous ground
necessary in a bonded system.