Main Switch Board (MSB) Safeties on ship


The safeties and protection of Main Switch Board (MSB) are:

  1. MSB should be dead front type. (i.e. All the live conductor should pass from behind of MSB).
  2. Reverse power trip, preferential trip, earthfault indicator, under voltage relay, overcurrent trip.
  3. The operating floor space in front and back of the MSB should be covered with anti skid, insulated rubber mats of minimum thickness of 15 mm or as approved by the class.
  4. The door opening mechanism must a have interlock with the power supply.
  5. MSB must be properly earthed.
  6. Every incoming and outgoing feed must be protected by a switch fuse, relay or circuit breaker.
  7. Insulation Resistance (IR) should not be less than 1 Mega Ohm in any case.
  8. Earth fault indication should be fitted and displayed in front panel.
  9. Charts indicating drill procedures in case of electric shocks must be displayed near MSB.
  10. Name tag / name plate indicating high voltage and danger sign should be fitted.
  11. Ebonite rod to remove the static charges.
  12. All the meters, switches, fuses, push button, indicating lamps, etc. should be in working condition and identified with individual name plate or tag.
  13. The enclosure should be drip proof.
  14. No water or oil pipes should pass above the Switch Board or MSB.
  15. he location where Switch Board or MSB is installed should have good ventilation, illumination and affected by minimum vibration.
  16. A spare rubber gloves.


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