How to Use Armored Cable for Wiring
Armored cable is an option for interior electrical wiring when wiring outlet boxes to each other. Armored cable contains two or three wire combinations in a rubber or thermoplastic cover. The covered wire combinations are inside the flexible steel of the armored cable. Using armored cable for wiring is a process that is easy to follow, but requires physical effort and knowledge of electrical wiring. This may not be a project for most do-it-yourself people, but those with electrical experience will find using armored cable for wiring to be an enjoyable challenge.
Thread armored cable through central holes in the structural members of the building. The holes should be at least 1/8 inch larger than the circumference of the armored cable so the cable is easy to thread through the holes. Do not mount the armored cable flush with notches in the studs and joists within a wall since a nail or screw from the installation of drywall or cabinets may pierce the cable and lead to a short circuit.
Use straps or staples at 4.5-foot intervals along the length of the armored cable when threading the cable between studs and joists. Use straps or staples to support the armored cable within one foot of each outlet box. This prevents excess pressure on the connections and splices between the end of the armored cable and the outlet box.
Connect or splice the armored cable only to the conductors within the outlet box. A length of armored cable must run from one outlet box to another outlet box with a connection at each box. Always do a practice run of armored cable from one outlet box to another before cutting the cable to its necessary length.
Use an armored-cable cutter or hacksaw to cut the cable. Leave an extra 8 inches at each end of the armored cable to ensure that enough wire is available to connect to the outlet box. Angle the hacksaw at 60 degrees when cutting armored cable. Near the end of cutting, stop and bend the armored cable back and forth until it snaps.
Strip the armor away from the wire leads at the end of the cable where it will connect to the outlet box. Strip away the fiber paper from the conductors at the end of the armored cable.
Mount an antishort bushing between the armor of the cable and the wire of the outlet box. This prevents damage to wires from the sharp edges of the armor.
Set the armored cable into the armored cable connector and tighten the screw that holds the cable in place. Thread the connector through the knockout opening in the outlet box and attach it to the box with a locknut from within the box. If the outlet box has internal armored cable clamps with mounting brackets, then loosen the screw for the clamp holder and thread the cable through the knockout opening.
Run the leads through the internal cable clamp, set the armored cable in place and tighten the clamp-holder screw. The clamp should fit into the ridges of the armored cable.
Things You Will Need
- Armored cable
- Armored cable straps or staples
- Armored cable cutter or hacksaw
- Antishort bushing
- Armored cable connectors