A. INTERIOR COMMUNICATION CIRCUITS|
|Class A-1 Circuits, Continuously Energized|
||Collision alarm system
||Low-pressure lubricating oil and high-temperature circulating water alarm system
||Auxiliary gyrocompass system|
||General alarm system
||General announcing system
||Telephone call system
||Submarine control announcing system
|Class A-2 Circuits, Continuously Energized Underway
||Diving alarm system
||Auxiliary stern diving plane angle indicator
||Shaft revolution indicator system
||Engine governor control and tachometer system
|1MB and 2MB
||Motor order telegraph
||Engine control indicatar system
||Automatic dead reckoning tracer system
||Rudder angle indicator system
||Main ballast indicator system
||Auxiliary bow diving plane angle indicator
||Hull opening indicator system
||Bow diving plane angle indicator
||Underwater log system|
||Stern diving plane angle inicator
||General announcing system|
||Submarine control announing system|
|Class A-3 Circuits, Fire Control|
||Torpedo firing system
||17GA1 and GA1
||Torpedo data computer|
||Target designation system
||17GA3 and 17GA4
||Forward and after gyro angle setting regulators|
||Torpedo ready light system
|Class A-4 Circuits, Convenience Circuits|
||Officers' call bells
|Circuits continuously energized||Yellow|
C. TYPES OF NAVY SHIPBOARD CABLES|
|Lighting, Power, and General Utility Cables
|SHFL||Single conductor, heat and flame resistant, leaded.
|DHFA||Double conductor, heat and flame resistant, armored.
|SHFA||Single conductor, heat and flame resistant, armored.
|DCOP||Double conductor, oil resistant, portable.
|SHFS||Single conductor, heat and flame resistant, switchboard cable.
|FHFA||Four conductor, heat and flame resistant, armored.
|TCOP||Triple conductor, oil resistant, portable.
| NOTE: Numbers following the above letters indicate the approximate circular mil area of each conductor with the last three digits omitted.
|Interior Communication and Fire Control Cables
|MHFA||Multiple conductor, heat and flame resistant, armored.
|MHFF||Multiple conductor, heat and flame resistant, flexible.
| NOTE: Numbers following these letters indicate the number of conductors in the cable. Each conductor has a cross-section area of about 2800 circular mils.
|TTHFA||Twisted pair, telephone, heat and flame resistant, armored.
| NOTE: Numbers following letters indicate number of pairs of conductors.
D. HOW TO READ A CABLE TAG ON A SUBMARINE|
In general, the designating letters for cable
tags on light and power circuits are as follows:
FB-light and power battle feeders
XFE-light and power emergency feeders
The numbers used in connection with the
designating letters are indicative of voltage. In
other words, the voltage may be determined
from the name-tag designation.
Example: 115 to 120-volt circuits are numbered
from 100 to 199, and 215 to 250-volt circuits
are numbered from 200 to 299.
A circuit designation such as FB-216 indicates
that it is a 250-volt circuit because the
number is in the range from 200-299.
Voltages of less than 100 volts are indicated
in the same general way as above, 40 volts being
numbered from 40 to 49, 60 volts from 60 to 69,
and so on.
Generator, bus tie, shore connections, main
motor, and battery cables use numbers preceded
by a zero to distinguish them from the regular
feeders, mains, and branches.
Example: A circuit marked FB-0211 would
still indicate 250 volts, but it is apparent that
it is not a major, or source of supply, cable.
When referring to the marking of lighting
and power cables the following terms are used.
A feeder is a cable emanating from a switchboard
or from the source of power to the switchboard.
A main is a cable emanating from a feeder.
A submain is a cable emanating from a
A branch is a cable emanating from a submain.
A subbranch is a cable emanating from a
When referring to the lighting system only,
the following definitions apply:
A lighting feeder is a circuit emanating from
the switchboard and supplying one or more
A lighting main is a circuit feeding from a
lighting feeder, supplied through a lighting
distribution panel, a feeder junction box, or feeder
A lighting submain is a circuit feeding from
a lighting main supplied through a distribution
A lighting branch is a circuit feeding from
a submain and supplying fixtures, lights, fans,
and other small equipment.
The same general arrangement applies to
power distribution. The following are examples
of cable markings:
FB-0210: Lighting feeder, supply to lighting
switchboard from source of supply.
F8-102: Lighting feeder from lighting
switchboard to distribution boxes on port side.
FB-101: Lighting feeder from lighting
switchboard to distribution boxes on starboard
18-FB-102: Lighting main connected to
feeder FB-102 and supplying after engine room.
18-FB-102-IS: Submain in after engine
FB-0218: Power feeder from main generator to
FB-200: Power feeder from after auxiliary
power switchboard to panel in crew's mess room.
1-FB-200: Power main from panel in
crew's mess room to galley range control panel.
1-F8-200A: Power submain from galley
range control panel to range cooking surface.
E. AMERICAN WIRE GAGE (A.W.G.) WORKING TABLE|
(U. S. Bureau of Standards)
|Gage No. in A.W.G.||Diameter in Mils||Cross Section||Gage No. A.W.G.||Diameter in Mils||Cross Section
|Circular Mils||Square Inches||Circular Mils||Square Inches
Ampere. The rate of flow of electricity. One
volt impressed on a circuit having a- resistance of
1 ohm results in a current flow of 1
Coulomb. The unit of quantity of electricity.
A current of 1 ampere, for example, is a
current flowing at the rate of 1 coulomb per
Volt. The electrical unit of pressure that causes
the electricity to flow.
Ohm. The electrical unit of resistance. If a
pressure of 1 volt is impressed on a circuit
and 1 ampere flows, that circuit has a resistance of 1 ohm.
Watt, kilowatt, horsepower. The units of
electrical power. One horsepower equals 746
watts. For rough estimates, to find horsepower,
multiply kilowatts by 1 1/3; to find
kilowatts, multiply horsepower by 3/4.
Henry. The unit of inductance. The ability of
a circuit to produce an emf by electromagnetic
induction when the current in the circuit changes.
Farad. The electrical unit of capacitance. A
condenser has a capacitance of 1 farad when
a potential difference of 1 volt between the
plates of the condenser will store up in it a
charge of 1 coulomb. Capacitance is generally
expressed in microfarads (one millionth of a farad).
G. CONVERSION FACTORS|
|To Convert||Multiply By
|Inches to centimeters||2.54
|Horsepower to watts||746
|British thermal units to foot pounds||778
|Kilograms to pounds||2.205
|Centigrade to Fahrenheit||9/5, then add 32
|Fahrenheit to centigrade||5/9, after subtracting 32
H. COMMONLY USED ELECTRICAL SYMBOLS|
I. SAFETY PRECAUTIONS|
1. Research has shown that at least 75
percent of all accidents is the result of
carelessness. Hurrying reduces caution and invites
accidents. Remembering the following rules will
help to prevent accidents:
Always take time to be careful.
Never take chances.
Turning one's head to engage in conversation
while working may result in an accident.
The importance of concentration on the job
cannot be overemphasized. The purpose of
safety rules should be to create a tendency to
think and act in terms of safety. A new man is
inclined to expose himself, as well as any equipment
on which he may be working, to danger
because of inexperience; an experienced man is
liable to do the same because of overconfidence
and habits of work he may have formed.
STOP. LOOK. THINK.
2. Men engaged in the following work
must wear eye protectors:
a. Acid working
b. Overhead drilling, reaming, etc.
c. Electric and gas welding, cutting, etc.
d. Grinding .
3. Only authorized persons are permitted
to work on electrical equipment.
4. When an electrical circuit is to be
overhauled or worked on, the main supply switches
or cutout switches in each circuit from which
power could possibly be fed should be secured
in the open position and tagged. The tag should
read, "This circuit was ordered opened for repairs
and shall not be closed except by direct
order of .................................." After
the work has been
completed, the tag or tags should be removed
by the person completing the repairs. In the
event that more than one working party is engaged
in repair work on an electrical circuit, a
tag for each party should be placed on the supply switches.
5. All electrical leads should be considered
as live until it is positively proved that they are
not. To check a circuit, test the live side with
the test lamp; then test the dead side with the
same lamp and retest the live side. This is to
make certain that the test lamp was in good
6. As a general rule use only one hand for
switching. Keep the other hand clear. Only one
switch should be touched at a time by one per
son. Before closing a switch, make certain that:
a. The circuit is ready and all moving
parts are free.
b. Men near moving parts are notified that
the circuit is to be energized.
c. Proper fuses are installed for protection.
d. The circuit is closed.
Ease the switch to a position for safe quick
action and then make the final motion positive
and rapid. In opening switches carrying current,
the break should be positive and rapid. An exception
to this rule is the case of the supply
switches to the main generator and main motor
field. These are opened slowly to permit the arc
to dissipate the stored inductive energy of the
coil in order to protect the insulation of the
7. Fuses are safety devices and should be
used as such. Fuse pullers made of insulating
material should be used for their removal or replacement. Fuses larger than 10-ampere rated
capacity should be removed and replaced only
after the circuit has been completely deenergized.
When a fuse blows, it should be replaced with a
fuse of the same rated ampere capacity. Never
short out a fuse.
8. Except for operating handles, all parts
of circuit breakers normally are conductors. In
opening and closing circuit breakers, observe the
a. Use only one hand.
b. Keep the hands clear of parts other than
the operating handles.
c. Touch only one breaker handle at a
d. Where positive and negative breakers
have two handles, they should not be closed at
e. Close the breaker first and then close
f. Trip the circuit breakers before opening
g. Never disable a circuit breaker.
h. Keep the face turned away while closing circuit breakers.
i. Never stand over a circuit breaker.
9. In so far as is practicable, repair work
on energized circuits should not be undertaken.
When repair work considered by the commanding officer as essential is undertaken on an energized
circuit, it should be accomplished by an
electrician's mate under the supervision of an
electrician or an experienced engineer officer.
In all such work every care should be taken to
insulate the person performing the work from
ground and to use every known safety precaution.
The following precautions must be observed:
a. Provide ample illumination.
b. Remove loose clothing.
c. Insulate worker from ground with dry
wood, several layers of dry canvas, or a sheet
of phenolic material or sandpaper.
d. Cover working metal tools with insulating
rubber tape, not friction tape, as far as
e. Insulate live metal parts near the place
where work is to be done.
f. If practicable, use only one hand in
accomplishing the work.
g. A rubber glove should be used on the
hand not used for handling tools. If the work
permits, rubber gloves should be worn on both
h. Have men stationed by circuit breakers
or switches, and telephones manned if necessary,
so that the circuit or switchboard can be deenergized
immediately in case of emergency.
i. A man qualified in first aid for electric
shock should stand by during the entire period
10. Cleaning of energized switchboards,
panels, boxes and the like should be limited to
removing loose dirt with a painter's duster
having no metallic parts and made of soft bristles
about 4 inches long.
11. Alcohol should not be used on energized
equipment or on equipment that is close
to a source of sparks. Alcohol should be exposed
in the smallest possible quantity, and should be
used only in well-ventilated compartments.
Wherever possible, no more than a pint of alcohol
should be taken to any one job.
12. Volatile liquids such as insulating varnish,
paint, lacquer, turpentine, or kerosene produce
inflammable vapors. In working with these
liquids ample ventilation should be provided to
prevent the accumulation of fumes.
One of the most common and useful cleaning solvents
is carbon tetrachloride. This substance must never
be used in a confined space
and should not be taken to sea in a submarine,
as the fumes are toxic and submarine crews
have been poisoned by them through leakage of
13. The risk of accidental contact with live
circuits always exists. As a general rule, persons
working around live circuits should not
approach closer than 1 foot regardless of voltage
except to accomplish a particular mission. While
accomplishing this mission - STOP, LOOK,
14. In case of an electrical fire, proceed as
a. Deenergize the circuit.
b. Report the casualty to the officer of the
deck by messenger or telephone.
c. Secure ventilation.
d. Extinguish the fire.
In extinguishing an electrical fire it should
be remembered that quick action is required
only in deenergizing the circuit. A CO2 fire
extinguisher directed at the base of the flame is
always best for electrical fires. Pyrene or carbon
tetrachloride is effective in extinguishing an
electrical fire that is wholly in the open. But when
used in a closed space, it forms a gas, as a result
of heat, that causes loss of consciousness. Pyrene
or carbon tetrachloride therefore should never
be used in a confined space for fire fighting.
Fresh water used intelligently is good for
extinguishing a fire. The use of salt water is
dangerous. Foam-type fire extinguishers should
never be used in fighting electrical fires. In case
of cable fires in which the inner layers of insulation,
or insulation covered by armor, support
combustion, the only positive method of preventing
the fire from burning the length of the
cable is to cut the cable and separate the ends.
15. Intentionally taking a shock from any
voltage is dangerous and is strictly forbidden.
Whenever it becomes necessary to check a
circuit to see if it is alive, a test lamp, voltmeter,
or other suitable indicating device should be
16. In the case of live circuits, never implicitly
trust insulating material. Insulating material
has been known to fail on more than one
17. If open-type electrical apparatus is in
operation when the presence of explosive vapor
is detected, the apparatus should be deenergized
by means of remotely located switches. The
switches should be opened only after it has been
ascertained that all persons are clear of the
18. No person should take loose metal
parts or liquids near or above a switchboard or
other open electrical apparatus. No person
should go above open electrical apparatus
without first removing all metal from his pockets.
Stowage or insertion of foreign articles in or
near switchboards, control appliances, panels,
and so forth is forbidden.
19. Covers for all fuse boxes, junction
boxes, lever type boxes, and wiring accessories,
in general, should habitually be kept closed.
20. In general, cables that are installed
where they will be subject to mechanical injury
should be protected within such exposed zones
by suitable metal casings.
21. Portable cables should be carefully selected
and should be of the proper length and
cross-sectional area. Spliced portable cables are
extremely dangerous and should not be used.
22. The static electrical charge retained by
electrical machinery when secured is in certain
cases sufficient to cause a severe shock. This
should be considered when making connections
to an apparently dead machine. Be safe-discharge
it to the ground.
J. FIRST AID|
1. Treatment for electric shock. A person
who has been accidentally shocked by electricity
and whose breathing has stopped is not
necessarily dead. He may be only stunned or
his breathing may have stopped only momentarily.
The following instructions should be followed
a. Break the circuit immediately.
b. Separate the victim from the live conductor
by a quick motion, using a nonconductor,
such as dry rope, a dry coat, or a dry board.
The victim's clothes, if dry, may be used to pull
him from the live wire. Do not use anything wet
c. Beware of touching the heels or soles
of the victim's shoes.
d. Do not touch his body with your hands
unless they are covered with rubber gloves, dry
clothing, or other nonconducting material.
e. If it is necessary to cut a live wire, use
an ax or hatchet with a dry wooden handle, or
f. If the victim is suffering from burns, use
the treatment for burns described in this section.
g. Apply warmth to the victim's body, rub
his skin and muscles, and administer stimulants
if he can swallow.
2. Resuscitation. As soon as the victim
is clear of the conductor, begin administering
artificial respiration. The patient's mouth should
be cleared of any obstructions such as chewing
gum or tobacco, false teeth, or mucus, so that
there is no interference with the entrance and
escape of air. The patient must be kept warm
during artificial respiration and it may be necessary
to cover him with blankets and work
through them, as well as to apply heat by means
of hot water bottles, hot bricks, and so forth.
Be careful not to burn the patient.
There are several accepted methods of applying
artificial respiration, but the best and
probably the least dangerous is the prone pressure,
or Schaefer, method which follows.
3. Artificial respiration, Schaefer method.
a. Position. 1) Place the patient on his stomach,
one arm extended directly overhead,
the other arm bent at the elbow and with the
face turned outward and resting on hand or
forearm, so that the nose and mouth are free
2) Kneel, straddling the patient's thighs.
3) Place the palms of your hands on the
small of the victim's back with your fingers
resting on his ribs, the little finger just touching
his lowest rib, the thumb and fingers in a natural
position, and the tips of the fingers just
out of sight.
b. First and second movements. 1) With
your arms held straight, swing forward slowly,
so that the weight of your body is gradually
brought to bear upon the patient. The shoulder
should be directly over the heel of the hand at
the end of the forward swing. Do not bend your
elbows. This operation should take about 2
2) Now immediately swing backward, so
as to remove the pressure completely.
3) After 2 seconds, swing forward again.
Repeat, 12 to 15 times a minute, the double
movement of compression and release; a complete
cycle of respiration in 4 or 5 seconds.
Continue artificial respiration without
interruption until natural breathing is restored.
Do not become discouraged if your efforts seem
to be in vain. Resuscitation often has to be
continued a long time before signs of life are
apparent. Do not discontinue your efforts until
you are absolutely certain that the patient is
dead. Sometimes, even after several hours work,
Do not feed the patient any liquids until
he is fully conscious.
When the patient revives, he should be kept
lying down to avoid strain on the heart. Give
him a stimulant, such as a teaspoonful of aromatic
spirits of ammonia in a small glass of
water or a hot drink of coffee or tea. Continue
to keep the patient warm and at rest.
As a general rule the victim should not be
moved until he is breathing normally and then
moved only in a lying position. Should it be
necessary to move the patient before he is
breathing normally, resuscitation should be
carried on during the time that he is being moved.
A brief return of natural respiration is not
a certain indication for stopping the resuscitation.
Not infrequently, the patient, after a
temporary recovery, stops breathing again. He must
be watched closely, and if natural breathing
stops, artificial respiration should be resumed at
In carrying on artificial respiration, it may be
necessary to change the operator. This change
must be made without losing the rhythm of respiration.
The relief operator should kneel behind
the man giving the artificial respiration, and at
the end of the movement, the operator crawls
forward while the relief takes his place. By this
procedure no confusion results at the time of
change of operator, and the established rhythm
4. Treatment of burns. Burns result
from exposure of the body to dry heat or to
strong acids and alkalis, while scalds follow
exposure to moist heat, such as hot water or
steam. These are serious accidents, attended, at
times, with marked shock, and their danger to
life depends more upon the extent of the body
surface involved, than the degree. The passage
of strong electric currents through the body also
For convenience, burns are classified as fol
First degree burns: Reddening of the skin.
Second degree burns: Reddening of the skin
with formation of blisters.
Third degree burns: Charring and destruction
of the deeper tissues.
There is usually considerable pain with
burns and, if the burned area is extensive,
Air must be excluded from the burned part.
This may be done by means of tannic acid jelly
dressings, or by a paste made with water and
baking soda, starch, or flour. If the burn was
caused by a caustic such as an acid or an alkali,
the acid should be neutralized with bicarbonate
of soda (ordinary baking soda). If the burn was
caused by an alkali, neutralize with a weak
solution of acetic acid (ordinary vinegar) before
the burned area is covered. Whenever possible,
burns should first be treated with tannic acid
jelly. If a person is extensively burned, the
quickest temporary means of excluding air is to
immerse the burned area or the entire body in
lukewarm water. Then, having everything in
readiness, carefully cut away the clothing, leaving
any that may be sticking to the burned skin.
The application of tannic acid jelly dressings
should follow and the patient put to bed. In
case the supply of tannic acid jelly is inadequate,
a satisfactory tannic acid solution can be
made by pouring one quart of boiling water over
2 1/2 ounces of tea leaves. Allow to steep for at
least 15 minutes, then strain. This solution can
be applied to the burned area by means of an
atomizer or sterile cotton applicators. Several
coats of the tannic acid solution are applied
while an assistant fans the areas to promote the
tanning process. The tannic acid unites with and
tans the tissues in the raw areas. When tanning
is complete, the burned areas are dark brown in
color, and when they have dried they are covered
with a hard, leathery crust of a dark brown
or black color. Unless infection occurs beneath
it, the crust should not be disturbed until it
begins to curl up at the edges and to peel off of
its own accord, when the loosened parts may be
cut away with sterile scissors.
The effectiveness of this method of treating
burns is seriously interfered with if oils, ointments,
or other greasy substances have
previously been applied to the burned areas. Any
oil, ointment, or grease that is present must be
gently but thoroughly removed with a sterile
swab and the area sponged with a weak solution
of sodium bicarbonate before the tannic acid
treatment is begun, even though it may cause
If tannic acid is not available, an excellent
dressing is a solution of ordinary baking soda
(2 tablespoonfuls in a pint of boiled water). A
salt-solution dressing is also good (a teaspoonful
of a common salt in a pint of boiled water). Do
not use strong antiseptics on burns. Soaking the
injured part in lukewarm water is good and is
very often useful to soak off clothing sticking
to a burned surface. If blisters have formed and
are painful, they may be opened by passing a
sterile needle through them and allowing the
fluid to escape. Do not destroy the skin raised
by a blister. The needle used may be sterilized
by burning in a flame. Do not put cotton next
to a burn; it sticks and causes trouble. In
dressing burns take a pad of sterile gauze, soak in the
solution, apply to the affected areas, and hold in
place by bandage. In removing the dressings, it
is often necessary to soak them off, and warm
water or one of the solutions mentioned above
may be used for this purpose.
The patient should be allowed to rest and
if there is much pain, phenobarbital and aspirin
tablets may be given. There may be considerable
shock accompanying the burn. A person badly
burned should be attended by a physician as
soon as possible.
Copyright (C) 2004 Maritime Park Association
All Rights Reserved
Version 1.10, 22 Oct 04