The function of an electrical system is to safely convey the power from the source to the various consumer equipment connected to it. A ship's electrical system can be of two types:
> Neutral Insulated system
> Neutral Earthed system
Neutral Insulated system
An insulated system is one that is totally electrically insulated from earth (ship’s hull). In a neutral insulated system, the star point of the source is not connected to earth. Hence there happens to be only 3 leads (3 phase wires R,Y,B) emanating from the source.
Neutral Earthed system
In a neutral earthed system, the star point is earthed to ground. So 4 wires emanating from source (3 phase and 1 neutral).
Note: In tankers it is not advised to have an earthed neutral system.An earth fault current occurring could circulate in the ship's hull within the hazardous zone which may cause an explosion of flammable cargo.
