Feeder Cable Connections While the electric generator is being installed and serviced, a part of your crew can connect it to the load. Essentially, this connection consists of running wire or cable from the generator to the load. At the load end, the cable is connected to a distribution terminal. At the generator end, the cable is connected either to the output terminals of a main circuit breaker or a load terminal  board.  Before  the  wires  are  run  and connections are made, it will be up to you to do the following: 1. Determine the correct size of wire or cable to use. 2.   Decide whether the wire or cable will be buried, carried overhead on poles, or run in conduit. 3. Check the generator lead connections of the plant to see that they are arranged for the proper voltage  output. The  information  contained  in  the  following paragraphs will help you in these tasks. CABLE  SELECTION.—If the wrong size con- ductor is used in the load cable, various troubles may occur. If the conductor is too small to carry the current demanded by the load, it will heat up and possibly cause a fire or an open circuit. Even though the con- ductor is large enough to carry the load current safely, its length might result in a lumped resistance that produces an excessive voltage drop. An excessive voltage drop results in a reduced voltage at the load end. This voltage drop should not exceed 3 percent for power loads, 3 percent for lighting loads, or 6 percent for combined power and lighting loads. Select a feeder conductor capable of carrying 150 per cent of rated generator amperes to eliminate over- loading  and  voltage  drop  problems.  Refer  to  the National   Electrical   Code^®   tables   for   conductor ampacities.  These  tables  are  310-16,  310-17,  310-18, and 310-19. You also should refer to the notes to ampacity tables following table 310-19. CABLE  INSTALLATION.—The   load   cable may be installed overhead or underground. In an emergency installation, time is the important factor. It may be necessary to use trees. pilings, 4 by 4s, or other temporary  line  supports  to  complete  the  installation. Such measures are temporary; eventually, you will have to erect poles and string the wire or bury it underground. If the installation is near an airfield, it may  be  necessary  to  place  the  wires  underground  at  the 3-6 beginning. Wire placed underground should be direct- burial. rubber-jacketed cable: otherwise, it will not last long. Direct burying of cable for permanent installation calls for a few simple precautions to ensure uninterrupted service. They are as follows: 1.   Dig the trench deep enough so that the cable can be buried at least 18 inches (24 inches in traffic areas and under roadways) below the surface of the ground to prevent disturbance of the cable by frost or subsequent surface  digging. 2. After laying the cable and before backfilling, cover it with soil free from stones, rocks. and so forth. That will prevent the cable from being damaged in the event the surrounding soil is disturbed by flooding or frost  heaving. GENERATING  PLANT  OPERATIONS When you are in charge of a generating station, you will be responsible for scheduling around-the- clock  watches  to  ensure  a  continuous  and  adequate amount of electrical power. Depending on the number of  operating  personnel  available,  the  watches  are evenly  divided  over  the  24-hour  period.  A  common practice is to schedule 6-hour watches, or they may be stretched  to  8-hour  watches  without  working  undue hardship on the part of the crew members. Watches exceeding 8 hours, however, should be avoided unless emergency  conditions  dictate  their  use. The duties assigned to the personnel on generator watches can be grouped into three main categories: (1) operating   the   equipment,   (2)   maintaining   the equipment,  and  (3)  keeping  the  daily  operating  log. Operating and maintaining the generating equipment will be covered in the succeeding sections of this chapter, so for the present you can concentrate on the importance   of   the   third   duty   of   the   station operator—keeping a daily operating log. The number of operating hours are recorded in the generating  station  log.  The  log  serves  as  a  basis  for determining  when  a  particular  piece  of  electrical equipment  is  ready  for  inspection  and  maintenance. The  station  log  can  be  used  in  conjunction  with previous  logs  to  spot  gradual  changes  in  equipment condition that ordinarily are difficult to detect in day- to-day operation. It is particularly important that you impress upon your watch standers the necessity for taking accurate readings at periods specified by local operating  conditions.