CHAPTER  6 ELECTRICAL  AND  ELECTRONICS  PRINTS When you have read and understood this chapter, you should be able to answer the following learning objectives. Describe shipboard electrical and electronics prints. Describe aircraft electrical and electronics prints. Explain basic logic diagrams on blueprints. This chapter is divided into two parts: electrical prints and electronics prints. Each part deals with the use of prints on ships and aircraft. ELECTRICAL PRINTS A large number of Navy ratings may use Navy electrical prints to install, maintain, and repair equip- ment.   In   the   most   common   examples,   Navy electrician’s  mates  (EMs)  and  interior  communica- tions   electricians   (ICs)   use   them   for   shipboard electrical   equipment   and   systems,   construction electricians (CEs) use them for power, lighting, and communications equipment and systems ashore, and aviation  electrician’s  mates  (AEs)  use  them  for aircraft electrical equipment and systems. These prints will  make  use  of  the  various  electrical  diagrams defined in the following paragraphs. A  PICTORIAL  WIRING  DIAGRAM  is  made  up of pictorial sketches of the various parts of an item of equipment and the electrical connections between the parts. An ISOMETRIC WIRING DIAGRAM shows the outline of a ship or aircraft or other structure, and the location of equipment such as panels, connection boxes, and cable runs. A  SINGLE-LINE  DIAGRAM  uses  lines  and graphic  symbols  to  simplify  complex  circuits  or systems. A   SCHEMATIC   DIAGRAM   uses   graphic symbols to show how a circuit functions electrically. An  ELEMENTARY  WIRING  DIAGRAM  shows how each individual conductor is connected within the various  connection  boxes  of  an  electrical  circuit  or system. It is sometimes used interchangeably with SCHEMATIC DIAGRAM, especially a simplified schematic  diagram. In a BLOCK DIAGRAM, the major components of equipment or a system are represented by squares, rectangles, or other geometric figures, and the normal order of progression of a signal or current flow is represented by lines. Before you can read any blueprint, you must be familiar with the standard symbols for the type of print concerned. To read electrical blueprints, you should know  various  types  of  standard  symbols  and  the methods of marking electrical connectors, cables, and equipments.  The  first  part  of  this  chapter  discusses these subjects as they are used on ships and aircraft. SHIPBOARD ELECTRICAL PRINTS To interpret shipboard electrical prints, you need to  recognize  the  graphic  symbols  for  electrical diagrams and the electrical wiring equipment symbols for ships as shown in Graphic Symbols for Electrical and Electronic Diagrams, ANSI Y32.2, and Electrical Wiring Equipment Symbols for Ships’ Plans, Part 2, MIL-STD-15-2. Appendix 2 contains the common symbols from these standards. In addition, you must also   be   familiar   with   the   shipboard   system   of numbering electrical units and marking electrical cables as described in the following paragraphs. Numbering Electrical Units All similar units in the ship comprise a group, and each group is assigned a separate series of consecutive numbers  beginning  with  1.  Numbering  begins  with units in the lowest, foremost starboard compartment and continues with the next compartment to port if it contains familiar units; otherwise it continues to the next aft compartment on the same level. Proceeding  from  starboard  to  port  and  from forward to aft, the numbering procedure continues until all similar units on the same level have been numbered. It then continues on the next upper level and so on until all similar units on all levels have been numbered.  Within  each  compartment,  the  numbering 6-1