Table 3-2.-Electrica1 Power and Lighting Cable Markings

Table 3-2.-Electrica1 Power and Lighting Cable Markings

(4-168-1)-4P-A(1) (fig. 3-8) identifies a 450-volt power

cable supplied from a power distribution panel on the

fourth deck at frame 168 starboard. The letter A indicates

Cable Marking

Remarks

that this is the first cable from the panel, and the (1)

6SG-4P-6S

450-volt generator power cable

indicates that it is the first section of a power main with

for ship service switchboard #6

more than one section.

supplied from ship service

The power cables between generators and

generator #6.

switchboards are labeled according to the generator

designation. When only one generator supplies a

6S4P-7S

450-volt bus-tie power cable

between ship service switchboard

switchboard, the generator will have the same number

#6 and #7.

as the switchboard plus the letter G. Thus, 1SG denotes

one ship's service generator that supplies the number 1

450-volt switchboard

3SA-4P-3SB

ship's service switchboard. When more than one ship's

inter-connecting power cable

service generator supplies a switchboard, the first

between sections A and B of the

switchboard.

generator determined according to the general rule for

numbering machinery will have the letter A immediately

6S-4P-31

450-volt BUS FEEDER power

following the designation; the second generator that

cable from #6 switchboard

supplies the same switchboard will have the letter B.

supplying load center

This procedure is continued for all generators that

switchboard #1 in zone 3.

supply the switchboards. Thus, 1SG and 1SGB denote

450-volt power FEEDER cable

31-4P-(3-125-2)

two ship's service generators that supply ship's service

from load center switchboard #1

switchboard 1S.

in zone 3 supplying power

Representative cable markings for power and

distribution panel 3-125-2.

lighting circuits are listed and explained in table 3-2.

450-volt MAIN power cable

(3-125-2)-4P-C

supplied from power distribution

PHASE AND POLARITY MARKINGS

panel 3-125-2, the third cable

from the panel.

Phase and polarity in ac and dc electrical systems

(3-125-2)-1P-C1

120-volt SUBMAIN power cable

are designated by a wiring color code as shown in table

supplied from power panel

3-2. Neutral polarity, where it exists, is identified by the

3-125-2, the first cable fed

white conductor.

through a transformer by the

MAIN listed above.

ISOMETRIC WIRING DIAGRAM

(3-125-2)-1P-CIB

120-volt BRANCH power cable

supplied from power panel

An isometric wiring diagram is supplied for each

3-125-2, the second cable fed by

shipboard electrical system. If the system is not too

the submain listed above.

large, the isometric wiring diagram will be covered by

(3-125-2)-1P-C1B2

120-volt SUBBRANCH power

one blueprint. For large systems, several prints may be

cable supplied from power panel

required to show the complete system. An isometric

3-125-2, the second cable fed by

wiring diagram shows the ship's decks arranged in tiers.

the branch listed above.

Bulkheads and compartments are shown, the centerline

1E-1EL-A

120-volt MAIN emergency,

is marked, and the frame numbers are shown (usually

lighting cable supplied from #1

every five frames). The outer edge of each deck is drawn

emergency switchboard-the first

to show the general outline of the shape of the ship. All

cable from the switchboard.

athwartship lines are shown at an angle of 30 degrees to

2-38-1)-1L-A1

120-voh SUBMAIN ship service

the centerline. Cables running from one deck to another

lighting cable supplied from

are drawn as lines at right angles to the centerline. A

lighting panel 2-38-1.

cable, regardless of the number of conductors, is

represented on an isometric diagram by a single line.

(2-38-1)-1L-A1C3

120-volt SUBBRANCH ship

service lighting cable supplied

The various electrical fixtures are identified by a symbol

from lighting panel 2-38-1the

number and their general location is shown. Thus, the

third cable supplied by BRANCH

isometric wiring diagram shows a rough picture of the

cable (2-38-1)-1L-A1C.

entire circuit layout.

3-14