The emergency switchboard is connected by
CASUALTY POWER DISTRIBUTION
feeders (fig. 3-3) to at least one and usually to two
different ship's service switchboards. One of these
A casualty power distribution system is installed
ship's service switchboards is the preferred (normal)
on certain types of ships to provide the means for
source of ship's service power for the emergency
making temporary electrical connections if the
switchboard, and the other is the alternate source. The
permanently installed ship's service and emergency
emergency switchboard and the distribution system
distribution systems cables are damaged. The system
are normally energized from the normal source of
is limited to those facilities that are necessary to keep
ship's service power. If this source of power should
the ship afloat and to permit the ship to get out of a
fail, bus transfer equipment automatically transfers
danger area. The system also supplies a limited
the emergency switchboard to the alternate source of
amount of power to armament and directors to protect
the ship's service power. If both the normal and
the ship when it is in a damaged condition.
alternate sources of power fail, the emergency
If the ship's service and emergency circuits fail,
generator will start automatically within 10 seconds
temporary circuits can be rigged. Also, the casualty
and the emergency switchboard will automatically
power distribution system can be used to supply power
transfer to the emergency generator.
to vital auxiliaries if any of the ship's service or
emergency generators can be operated.
The emergency power distribution system is 450
volts, 3 phase, 60 Hz with transformer banks at the
C o m p o n e n t parts of the casualty power
emergency distribution switchboards to provide
distribution system include permanent and portable
120-volt, 3-phase power for the emergency lighting
cables, bulkhead and switchboard terminals, risers,
and portable switches.
Figure 3-3.-Emergency and ship's service distribution system interconnections.