It is the task of a CE to ensure the proper operation of all power tools within his or her realm of responsibility. The program itself will be formulated by higher authority. The best way to perform this task is to develop a good inspection and maintenance program. Periodically, you should check all power tools for loose connections, pitted contacts, improper mounting of switches, and so forth.
The inspection and maintenance of power tools go hand in hand, and, in most cases, a problem discovered during inspection is corrected on the spot and requires no further work until the next inspection.
Test equipment and experienced Construction Electricians are not always needed to locate problems. Anyone who sees a ground wire dangling beneath a lightning arrester might suspect a problem. Little skill is required to consider an electrical service problem as a possible reason for the lack of power in a building.
Arcing, loud noises, and charred or burned electrical equipment sometimes indicate electrical faults; however, hidden, noiseless circuit problems are much more common and usually much harder to locate.
The right test equipment and the Construction Electrician who knows how to use it are a valuable combination for solving electrical circuit problems.
No attempt will be made in this chapter to explain the internal workings of test equipment, such as meter movement or circuitry. Information on these subjects is covered in Navy Electricity and Electronics Training Series (NEETS) modules, published by the Naval Education and Training Program Management Support Activity. Test equipment is discussed in Modules 3 and 16. Your education services officer (ESO) should stock the NEETS modules. If not, he or she can order them for you. Other information on the use of test and circuit measuring equipment is included in modules throughout the NEETS series. This section introduces to you the types of test equipment used by the Construction Electrician in the field.
Naval Facilities Command (NAVFAC) requires that tests of electrical equipment be performed under the supervision of qualified electrical personnel. If in-house personnel are not available for these tests, the services of a qualified electrical testing contractor may be used. If you do not know how to do certain tests that must be performed, go to your seniors (crew leader and/or project chief). Be certain that you can perform the test safely before starting the test procedure.
A meter used to measure the flow of electric current is a current meter. Current meters that measure current in amperes are called ammeters. The ammeter is connected in series with the circuit source and load. Panel-mounted ammeters, such as those used in power plants, are permanently wired into the circuit. Figure 7-17 shows two typical panel-mounted ammeters.
Portable ammeters are temporarily connected into a wiring system at whatever point in the system a current reading is desired; for example, feeder current is measured by opening the feeder and wiring the meter in series with the feeder source and load. Circuits branching off the feeder may be opened and an ammeter inserted into the branch.
Using a clamp-on ammeter (fig. 7-18) is an exception to the rule previously stated requiring ammeters to be series-connected. The clamp-on ammeter consists in part of clamp-on transformer jaws that can be opened and placed around a conductor. The
Figure 7-17. - Typical panel ammeters.Continue Reading