16.-05. - Installation of Wires and Cables. Installation of wire in conduit is made with the use of pull lines or fish tapes and an approved wire-pulling lubricant. Suitable equipment should be provided to prevent cutting or abrasion of conductor insulation during the pulling of the wires. Lubricating compound must not have a harmful effect on the conductor insulating materials. All wires in a conduit are bundled and pulled at one time. Pulling lines are attached by direct connection to the conductors or by the use of a cable grip. Slack is provided at attachment of devices or splicing. In outlet boxes, for future installation of wiring devices, the ends of wires are insulated with tape or a suitable wire connector. All conductors of each circuit in a junction box containing multiple circuits must be permanently identified with suitable labels.
Nonmetallic-sheathed cable may be installed exposed on walls and ceilings in protected areas or concealed in hollow walls, under floors, or above ceilings. Provisions for outlets and switches are made by running the cable into outlet boxes. All splices are enclosed in outlet or junction boxes; this requirement applies to both exposed and concealed installation.
The moment your battalion or unit receives orders to undertake a major construction project, watch for the arrival of sets of drawings and specifications, which are usually provided well in advance of the deployment period. These drawings and specifications will also be the basis for the P&E and scheduling. Take a look at the specifications. After you advance in rate, especially if you are concerned with P&E, it will be your responsibility to study the applicable specifications thoroughly.
NAVFACENGCOM has prepared specifications that cover practically every subject on naval construction. These specifications are the standards followed by the NCFabove all other specifications that may be available.
As a Construction Electrician you will be required to read and interpret drawings and specifications, sketches, and electrical diagrams. Before you can work with drawings effectively, you must know how to interpret electrical symbols correctly. Knowing how to draw and interpret freehand sketches is also important. You will see how the different parts of a drawing relate to the overall plan the drawing represents. You will also learn to recognize the different types of drawings and their uses.
One of the most important symbols to use right at the beginning of a new job is the directional symbol. This symbol, which is usually an arrow labeled "N" for north, enables the reader of a construction drawing to orient it. A drawing is properly oriented when it is held so that the north arrow shown on the drawing is pointing toward north. Construction Electricians sometimes find themselves standing in open ground with only a drawing and an area staked off by the Engineering Aid who tells them where to start shoveling for an underground conduit run. The drawing must be properly oriented so the reader can relate the information on it to the surrounding area. Understanding common standard symbols, such as the north arrow mentioned above, is a must for some one who expects to do well inelectrical construction work.
Some of the most common symbols you will see in building construction work are listed in figure 2-5. These symbols were selected from ANSI Y32.91972. Study these symbols carefully. A good way to memorize them is to copy each symbol several times while thinking of the electrical component or device it represents. Learn to relate each symbol mentally to the component it represents whenever you see the component. For example, as you pull the wire through a conduit in a floor slab, you might try to recall the symbol mentally for "wiring concealed in floor." When you walk into the company office and see a duplex receptacle outlet, you should think about its symbol. This practice will enable you to associate symbols to actual electrical devices. This type of training will help you become a better CE.
Although figure 2-5 shows some of the most common standard symbols, these are by no means the only ones you will see in your work. Sometimes a symbol for a particular component or device may have been created by the architect or engineer who developed the drawing. For various reasons, some of the symbols on a drawing may not be standard. Many times you will figure out what a symbol means by analyzing it and thinking about what it looks like. The legend on a drawing should show any nonstandard symbols and their meanings.Continue Reading