RIGGING CASUALTY POWER

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