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. 12-14