Shipboard Electrical Prints

All similar units in the ship comprise a group, and

WIRING (CONNECTION) DIAGRAMA

each group is assigned a separate series of consecutive

diagram that shows the individual connections within a

numbers beginning with 1. Numbering begins in the

unit and the physical arrangement of the components.

lowest foremost starboard compartment, and the next

SCHEMATIC DIAGRAMA diagram that uses

compartment selected is to port of the first if it contains

graphic symbols to show how a circuit functions

similar units; otherwise, the next aft on the same level.

electrically.

Proceeding from starboard to port and from forward

ELEMENTARY WIRING DIAGRAM(1) A

to aft, the numbering procedure continues until all

shipboard wiring diagram that shows how each

similar units on the same level have been numbered;

conductor is connected within the various connection

then it continues on the next upper level, and so on, until

boxes of an electrical circuit or system. (2) A schematic

all similar units on all levels have been numbered.

diagram; the term elementary wiring diagram is

Within each compartment, the numbering of similar

sometimes used interchangeably with schematic

units proceeds from starboard to port, forward to aft, and

diagram, especially a simplified schematic diagram.

from a lower to a higher level. Within a given

compartment, then, the numbering of similar units

BLOCK DIAGRAMA diagram in which the major

follows the same rule; that is, lower takes precedence

components of a piece of equipment or system are

over aft, and starboard takes precedence over port.

represented by squares, rectangles, or other geometric

Electrical distribution panels, control panels, and so

figures, and the normal order of progression of a signal

on, are given identification numbers made up of three

or current flow is represented by lines.

numbers separated by hyphens. The first number

SINGLE-LINE DIAGRAMA diagram that uses

indicates the vertical level, at which the unit is normally

single lines and graphic symbols to simplify a complex

accessible, by deck or platform number. Decks of Navy

circuit or system.

ships are numbered using the main deck as the starting

point. The numeral 1 is used for the main deck. Each

To be able to read and verify the accuracy of any

successive deck above the main deck is numbered 01,

type of blueprint, you must be familiar with the standard

02, 03, and so on, and each successive deck below the

symbols used for the type of print concerned. Reading

main deck is numbered 2, 3, 4, and so on.

electrical blueprints requires a knowledge of various

The second number indicates the longitudinal

types of standard symbols and, in addition, a knowledge

location of the unit by frame number. The third number

of the methods of marking electrical conductors, cables,

indicates the transverse location by the assignment of

and equipments.

consecutive odd numbers for centerline and starboard

locations and consecutive even numbers for port

SHIPBOARD ELECTRICAL PRINTS

locations. The numeral 1 indicates the lowest centerline

(or centermost) starboard component. Consecutive odd

Various types of electrical drawings and diagrams

nun numbers are assigned components as they would be

are used in the installation and maintenance of shipboard

observed first as being above and then outboard of the

electrical circuits, systems, and components.

preceding component. Consecutive even numbers

similarly indicate components on the port side. For

To interpret shipboard electrical prints, you must be

example, a distribution panel with the identification

able to recognize the graphic symbols for electrical

number 1-142-2 will be located on the main deck at

diagrams and the electrical wiring equipment symbols

frame 142 and will be the first distribution panel on the

for ships as shown in ANSI/IEEE STD 315A-1986 and

port side of the centerline at this frame on the main deck.

MIL-STD-15-2. Common symbols from these

Main switchboards or switchgear groups supplied

standards are shown in table 3-1. In addition, you must

directly from ship's service generators are designated

also be familiar with the shipboard system of numbering

1S, 2S, 3S, and soon, as necessary to designate all ship's

electrical units and marking electrical cables as

service switchboards. Switchboards supplied directly

described in the following paragraphs.

by emergency generators are designated 1E, 2E, 3E, and

so on, as necessary to designate all emergency

NUMBERING ELECTRICAL UNITS

switchboards. Switchboards for special frequency

(other than the frequency of the ship's service system)

have ac generators designated 1SF, 2SF, and so on, as

Electrical units and other shipboard machinery and

necessary to designate all special frequency

equipment are numbered as described in the following

switchboards.

paragraphs.

3-10