SHIPBOARD ELECTRICAL
SYSTEMS AND CONNECTIONS
As a Fireman, you should be familiar with the
power and lighting distribution systems, and shore
power connections. You will find greater detail
on this and other shipboard electrical equipment
in chapter 320, Naval Ships’ Technical Manual.
POWER DISTRIBUTION SYSTEMS
A power distribution system carries power
from the generator switchboards to every part of
the ship. This system consists of feeders, mains,
submains, load center panels, and distribution
boxes. The most important auxiliaries are supplied
with normal, alternate, and emergency feeders
through automatic bus transfer units, each with
a separate source of power. Casualty power
systems are installed aboard ship to provide
electrical connections when both ship’s service and
emergency electrical systems are damaged.
LIGHTING DISTRIBUTION SYSTEMS
Lighting distribution systems are necessary to
light the ship and to assist personnel in controlling
damage. Two lighting systems are installed aboard
combatant ships. These are ship’s service lighting
and emergency lighting. The ship’s service lighting
normally supplies all lighting fixtures. Emergency
lighting circuits are supplied to vital machinery
spaces, the radio room, the combat information
center, and other vital spaces. The emergency
lighting system receives power from the ship’s
service generators; but if normal power is lost,
the emergency system is automatically powered
by the emergency generators. Lighting distribution
systems are similar to power distribution systems
except for the following differences:
1. They are more numerous.
2. They have lower voltages (120 volts).
3. They have smaller panels and cables.
If an emergency power system is not installed,
alternate supplies from another ships’ service
source can provide for services selected according
to the basic principles of an emergency lighting
system.
SHORE POWER CONNECTIONS
Shore power connections are installed at or
near suitable weather deck locations. At these
locations, portable cables from the shore, or from
a ship alongside, are connected. Power can be
supplied through these connections to the switch-
board when ship’s service generators are not in
operation.
ELECTRICAL SAFETY
PRECAUTIONS
There are certain safety precautions you
should observe when working with or around
electrical appliances and equipment. The following
are some of the most common electrical safety
precautions all shipboard personnel are required
to follow:
Do not attempt to
electrical equipment
electrical work to
electricians.
maintain or repair
yourself. Leave the
the EMs and IC
Check personal electrical equipment
through the EMs to see if it can be used
aboard ship.
Observe and follow all pertinent instruc-
tions and electric warning signs aboard
ship.
Observe all safety precautions regarding
portable electric lights and tools. (Use
rubber gloves and goggles.)
Remember, 120-volt electricity is
dangerous, especially aboard ship.
Do not touch or operate any device
has a danger or caution tag attached
without first contacting the EOOW.
very
that
to it
Do not go behind electrical switchboards.
Do not touch bare electric wires or
connections; assume all circuits to be
ALIVE.
Do not remove steamtight globes from
lighting fixtures.
Do not remove battle lanterns from their
locations.
Do not use manually operated hand battle
lanterns for unauthorized purposes. Each
person should have his/her own flashlight.
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