Main Switch Board (MSB)


Main Switch Board (MSB)

MSB Cabinet is made of Steel (Sheet)

Cabinet is divided into many sections/compartments

Electrical Power from the Generators is collected in the MSB through Generator Switch Board/Panel

From the MSB, Electrical Power is distributed to various Utilisation Devices through Group Feeder Panels / Group Starter Panel

440 V Devices are supplied from 440 V Bus Bars (440 V Feeder Panels / Group Starter Panel)

440 V is step down to 220 V using a Step Down Transformer

220 V Devices are supplied from 220 V Bus Bars (220 V Feeder Panel/Section)

Shore Supply (during Dry Dock) is connected to MSB

MSB Supply the power to Emergency Switch Board (When Main Generators are running)

Front door & back doors are hinged to facilitate operation, inspection &cleaning

Operating handles and push buttons of the devices are mounted on the front doors/panels

MSB is arranged symmetrically

Generator Switch Board /Panels in the Middle

Feeder Panels/Group Starter Panels distributed equally on either side of the GSB

Devices / Instruments / Components fitted in MSB

Switch Gears/Circuit Breakers

440 V Main Bus Bars ( 3 no’s)

220 V Bus Bars ( 3 no’s)


Monitoring & Controlling Systems / Devices

Measuring & Indicating Instruments



Frequency meters

Watt meters

Synchronising Unit (Synchronoscope)

Power Factor meter

Insulation Resistance meter

Step Down Transformers

Safety provided in MSB

1.Circuit Breakers (With Arc chute)

2.Short Circuit Trip

3.Overload Trip

4.Low Frequency Trip

5.Under Voltage Trip

6.Phase Imbalance Trip

7.Reverse Power Trip

8.Preferential Trip

9.Over Speed Trip


11.Earth Fault Indicators

12.Panel Doors are Earthed

13.Ebonite Rod

14.Rubber Mat in front and back of MSB

15.Dead Front Type

16.0.6 metre gap between MSB & bulkhead

17.No Water or Steam or Oil pipeline to pass in the vicinity

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