The normal lighting system of a ship, also known as the main lighting system, is distributed in various living and working places inside and outside the ship, providing sufficient illumination for each compartment and workplace.

The characteristic of this system is that the lighting busbar on the main distribution board directly supplies power to each lighting distribution box, and then the lighting distribution box supplies power to the lighting fixtures in adjacent cabins or areas;

The lighting voltage is generally AC or DC 110 V or 220 V;

Different cabins and locations have different lighting requirements; All lighting fixtures are equipped with control switches.   

Normal lighting is the main lighting of the entire ship, powered by the ship's main generator, and should illuminate all areas where the ship lives and works.

Normal lighting includes:

(1) The main lighting of the cabin, such as most of the overhead lights;   

(2) Local or auxiliary lighting, such as bed lamps, wall lamps, wash lamps, etc;

(3) Strong lighting for loading and unloading cargo;

(4) More than half of the indoor and outdoor walkways are illuminated;

(5) Each compartment must be equipped with sockets, etc.       

Non essential equipment such as electric fans, refrigerators, and cabin electric heaters with a rated power of 0.25 kW or less may also be included in the normal lighting system.