Tag Archives: Safeties In Main Switch Board

Construction of a Main Switch Board (MSB) used in Ships

A main switch board is an integrated assembly of switching controls, regulator equipment, measuring instruments, indicators and protective devices, and is a necessary apparatus for efficient centralized control of the electrical systems and power operated equipment in ships.

This main switch board distributes electrical power to the electrical loads in various locations in the ship. Should a fault occur at a place, an appropriate protective device in the switchboard will operate to disconnect the faulted circuit. One or more generators are operated and controlled, depending on the size of load, from this main switch board, and supply the power to the feeder circuits through the respective feeder panels.


A dead front type switch board have no live parts on the front of the panel. Each frame work is rigidly constructed of steel angles for vibration resistance and to which a door type panel or panels of 2.3 mm thick sheet steel are hinged at one side with the other side latched for securing it or them in place.

Where inspection or servicing of the internal parts is required, turn each knob latch 90 degrees anticlockwise to unfasten, then the panel is opened and held open by means of a metal bar. Internal devices (instrument transformers, relays, etc.) are so mounted that they are resistant to vibration and impact, yet easily replaceable from the front or back of the switch board.

Insulating material used is mostly laminated-phenolic and special attention is paid to the configuration for temperature and moisture stability,trouble-free operation and safety.