areas must be patched once the wiring is installed. The second way is to remove a small portion of the finished area (only enough to give access to voids in walls, ceilings, etc.) and then fish the wires in. The removed portions of the finished area are then replaced after the wiring is complete.
Where outlet boxes are used, they should be designed for installation in the type of finish in the area. Means of securing the boxes to some structural member - like mounting ears or holding devices-should be given consideration.
Another method of providing outlets in a finished area is to remove the existing baseboard and run the conductors in the usual groove between the flooring and the wall and then replace the baseboard. This method requires less work (cutting and patching) than most other methods when disturbing a finished area. There is also a type of metal baseboard on the market that may be installed along the floor line and used as a raceway. Most types are provided with two compartments for wires: one for power and one for low-voltage wiring. Using this metal baseboard provides a simple means of routing wires for security/fire-alarm systems with very little cutting or patching. In most cases, wires can be fished from the baseboard up to outlets on the wall, especially if the outlets are less than 3 feet (0.9 m) above the floor. However, if this is not practical, matching surface molding can be installed to blend in very nicely with the baseboard.
When a lot of cutting and patching is required in a finished area, many installers will have a carpenter do the work. The carpenter may know some tricks that will help the alarm-system installers get the system in with the least amount of difficulty. Also, any cutting or patching will be done in a professional manner.
Before doing any actual cutting on an existing building to install security/fire-alarm components, the installer should carefully examine the building structure to ascertain that the wires may be routed to the contacts and other outlets in a relatively easy way. It is possible that a proposed outlet location, for example, could be moved only a foot or two to take advantage of an existing chase. Perhaps a smoke detector or similar component was originally located in a ceiling with insulation, which would make the fishing of cables very difficult. If the detector could be located on a ceiling containing no insulation, the job would be greatly simplified.
When cutting holes in ceilings for outlets, you should spread a drop cloth or paper underneath to catch all dust and dirt. Sometimes an old umbrella can be opened and hung upside down under the spot in the ceiling where the hole is being made to catch the debris and keep it off the rugs and furniture.
Holes for wires and components can be cut through plaster with a chisel, through wood with a keyhole saw after first drilling two or four pilot holes, and in brick or other masonry with a masonry chisel or rotary hammer. To locate the exact spot to cut these openings, first cut a small hole in the center of the spot where the larger one will be made. This hole may then be used to locate the area between studs or--in the case of very old buildings--the cracks between the plaster laths. It is then possible to shift the mark for the outlet openings so that all obstacles can be avoided and the outlet box or component can be properly anchored.
There are a number of ways to pull and fish wires into walls and openings in finished buildings and, with a little ingenuity and careful thought, workers should be able to solve almost any problem of this kind that they may encounter.
When you are pulling wires into spaces between the joists in walls, a flashlight placed in the outlet box hole is often a great help when feeding the wires in or catching them as they are pushed near the opening. Under no circumstances should a candle or other open flame be used for this purpose. If one must see farther up or down the inside of a partition, a flashlight and a mirror used in combination, as shown in figure 8-5, is a great help. Many installers like to make their own mirror by gluing a small 2- by 3-inch (5- by 8-cm) compact mirror on a handle, resembling a wooden tongue depressor. Any type of small flashlight may be used.
Figure 8-5. - A flashlight and mirror used in combination are useful for viewing conditions inside of partitions.Continue Reading