The Golden State: Where & How to Live, Secure, Visit, Enjoy and Thrive in California
Practical Electricity And House Wiring
Wiring Houses After They Are Built
Old Work.—In this chapter we will assume that the house which we wired in Chapters 12 to 16 while it was being built, has been completed before we start wiring. The wiring of buildings after they are completed is known as "old work."
Our electrical problems will not be different from those encountered while wiring the house as it was being built, for we will have the same wires leading to the same outlets as before. However, we cannot run our wires in the shortest distances without tearing up most of the house; instead we must run our wires or cables up and down within walls and through the ceilings in round-about fashion, so as to reduce the amount of opening of walls, ceilings, and floors to a minimum. In other words, our new problems instead of being electrical are mostly problems of carpentry.
In wiring with the knob-and-tube method in "old work," the Code does not require that wires be supported at intervals as in "new” work." It does, however, require that each wire be encased in a separate piece of loom which must be continuous from one outlet to the next. Since the cost of two wires plus two lengths of loom is usually considerably in excess of the cost of an equivalent length of cable, and since it takes much more time to fish two separate lengths of wire and loom through the walls than one piece of cable, the knob-and-tube system is not very frequently used in "old work."
To install rigid conduit in a building after it has been completed, requires entirely too much carpentry, opening up of walls and floors, to be practical. Its use, therefore, is never required.
Armored cable or non-metallic sheathed cable provide the ideal method in wiring old buildings. Cable requires very little space, is readily fished through small openings, and requires less work than any other system. It does not have to be supported at intervals as in "new work."
In some localities armored cable is prohibited even in "old work," and ordinances require the use of flexible conduit. This, as explained in a previous chapter, is very similar to the armor of armored cable, except larger. Where required, it is installed in exactly the same fashion as armored cable, which will be covered in this chapter, except that the wires are pulled in after the flexible conduit has been installed.
Draw a plan as you did in Chapter 12, locating your outlets; serious consideration should be given to the precise location so that a minimum of openings need to be cut into the walls to bring cable from one outlet to another. Frequently moving an outlet a few inches will save much labor.
