service power by means of a transfer switch near
the load.
If both the normal and alternate sources of the
ship’s service power fail because of a generator,
switchboard, or feeder casualty, the vital
auxiliaries can be shifted to an emergency feeder
that receives power from the emergency
switchboard.
If the ship’s service and emergency circuits fail,
temporary circuits can be rigged with the casualty
power distribution system and used to supply
power to vital auxiliaries if any of the ship’s
service or emergency generators can be operated.
The casualty power system includes suitable
lengths of portable cable stowed on racks
throughout the ship. Permanently installed
casualty power bulkhead terminals form an
important part of the casualty power system (fig.
3-21). They are used for connecting the portable
cables on opposite sides of bulkheads, so that
power may be transmitted through compartments
without loss of watertight integrity; also included
are permanently installed riser terminals between
decks.The vital equipment selected to receive
casualty power will have a terminal box mounted
on or near the equipment or panel concerned and
connected in parallel with the normal feeder for
the equipment.
Sources of supply for the casualty power
system are provided at each ship’s service and
emergency generator switchboard. A casualty
power riser terminal is installed on the back of the
switchboard or switchgear group and connected to
the buses through a 225- or 250-ampere AQB
circuit breaker. This circuit breaker is connected
between the generator circuit breaker and the
generator disconnect links. By opening the
disconnect links, you will isolate the generator
from the switchboard. Then, it can be used
exclusively for casualty power purposes.
RIGGING CASUALTY POWER
To eliminate the necessity of handling live
cables and to reduce the hazards to personnel and
equipment, definite procedures must be followed
and safety precautions must be observed in
rigging casualty power.
Figure 3-21.-Rear of switchboard showing casualty power terminal.
3-14
