Introduction in marine electrical system

The distribution system is an extension of the generator.

All electrical loads are connected in parallel with the generator terminals through connection points (nodes) at the switchboards and distribution panels. Through proper design, large cables (feeders) provide power to bus bars inside the switchboards and each distribution panel. The use of a single feeder cable will eliminate dozens of individual parallel cables that would have otherwise been needed for the connection between the generator and each load.

The distribution system is also designed to protect the overall electrical environment from electrical component casualties. Circuit breakers and fuses are installed in switchboards and distribution panels to separate abnormally operating electrical apparatus from the rest of the system. Each circuit protective device, from the generator to the load, is set at decreasingly smaller ampacity increments. When all overcurrent and short circuit protective devices are properly selected and correctly adjusted, selective tripping can be provided.

Selective tripping allows an abnormal circuit to be separated from the electrical distribution system very close to the fault.

The switchboard receives power directly from the generators. In turn, feeders extend from the switchboard circuit breakers to the power distribution panels, lighting distribution panels, or large motor circuits. Branch circuits leave the distribution panel circuit breakers and provide power to individual loads.