The Golden State: Where & How to Live, Secure, Visit, Enjoy and Thrive in California
Practical Electricity And House Wiring
Wiring With Armored Cable
We will now wire the same house we have already wired with non-metallic sheathed cable, but we will use armored cable.
Definition of Armored Cable.—Armored cable, as we learned in Chapter 10, consists of one or more rubber covered wires, covered with a layer of steel which is applied in a spiral form, so as to be flexible. Between the armor and the wires is a layer of heavy kraft paper, as in the case of non-metallic sheathed cable. Each wire in the cable is of a different color; when there are two wires, one is black, the other white; when there are three, the third is red.
Armored cable wiring is like conduit wiring, in that the flexible steel armor corresponds to the steel conduit itself. However, instead of having to pull in the wires, the wires are inside the armor and are installed automatically as the cable is installed.
Splices Not Permitted.—In armored cable wiring, no splices are permitted between outlets. All connections must be inside outlet boxes. If two short pieces of cable are to be used, install an outlet box where they meet, solder white to white, black to black, tape and close the box with a blank cover, just as when using non-metallic sheathed cable.
Supporting Cable.—Where cable runs crosswise across studs or joists, run it through holes bored through the center of the joist or stud. If it runs parallel with joist or stud, anchor it at least every 41/2 feet, as required by the Code; it must also be anchored within 12 inches of every outlet box. For this purpose ordinary pipe straps may be used though the use of "BX staples" illustrated in Fig. 148 is less expensive and faster. Where bends are necessary, do not make them too sharply lest the armor be split open; the Code provides all bends shall be made so that if completed into a complete circle, the diameter of the circle would be not less than ten times the diameter of the cable. In accessible attics or roof spaces, if the cable is run across the face of studs, rafters, or floor joists (instead of through bored holes), a guard strip at least as high as the cable must be run along the cable; a strip of 1 X 2" lumber will serve the purpose.
