Chapter 20. -SHIPBOARD ELECTRICAL SYSTEMS 



work on electrical equipment should be per- 

 formed only by duly authorized and assigned 

 persons. 



When any electrical equipment is to be 

 overhauled or repaired, the main supply switches 

 or cutout switches in each circuit from which 

 power could possibly be fed should be secured 

 in the open position and tagged. The tag should 

 read: "This circuit was ordered open for re- 

 pairs and shall not be closed except by direct 

 order of ." The name given is usu- 

 ally the name of the person directly in charge 

 of the repairs. After the work has been com- 

 pleted, the tag or tags should be removed by 

 the same person. 



The covers of fuse boxes and junction boxes 

 should be kept securely closed except when work 

 is being done. Safety devices such as interlocks, 

 overload relays, and fuses should never be 

 altered or disconnected except for replace- 

 ments. Safety or protective devices must never 

 be changed or modified in any way without spe- 

 cific authorization. 



Fuses should be removed and replaced only 

 after the circuit has been deenergized. When a 

 fuse blows, it should be replaced only with a 

 fuse of the correct current and voltage ratings. 

 When possible, circuit should be carefully 

 checked before the replacement is made, since 

 the burned-out fuse is often the result of a 

 circuit fault. 



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