Question

With reference to the provision of a shore electrical supply to a ship:

(a) Sketch an arrangement for taking A.C. shore supply and checks to be carried out prior taking shore connection (10)

(b) Describe the method of safely connecting the arrangement sketched in (a) to the shore supply. (6)

Answer 1

Part (a)

A visual inspection should be done to identify any visible damage to the shore power cable, such as cuts, fraying, or signs of overheating.
Measure the insulation resistance of the shore cable and the ship’s shore connection box to ensure proper insulation.
Verify the working condition of fuses by performing a continuity test.
Confirm the functionality of indication lamps for clear status monitoring.
Ensure that the shore supply circuit breaker is switched off before any connections are made.
Confirm that the emergency generator is set to manual mode to avoid unintentional operation during shore supply connection.
Inspect the connecting terminals on both the shore connection box and the cable lugs to ensure they are clean, secure, and free from corrosion.

Part (b)

Turn off all non-essential equipment to minimize load requirements.
Keep standby diesel generators in manual mode to prevent automatic starting.
Announce a potential blackout to notify the crew and prepare them for any temporary power loss.
Keep a hand safety torch readily available to handle temporary darkness during the transition.
Shut off the ship's power and alternator.
Connections of shore cables are to be made only after shutting off the ship's power & alternator.
Connect the ship’s hull to the shore earth point to provide proper grounding and ensure safety from electrical faults.
Connect the shore supply cables to the circuit breaker and measure the voltage and frequency of the shore supply to confirm compatibility with the ship's electrical system.
Verify the phase sequence using the Phase Sequence indicator to avoid incorrect motor rotation or electrical malfunction.
Ensure that all lids and circuit breakers are switched off before finalizing connections.
Once all conditions are satisfied, switch on the shore supply circuit breaker.
Start one motor and confirm the correct direction of rotation to validate the phase sequence.
Begin connecting essential systems and equipment to the shore supply one at a time. Monitor the load to ensure it does not exceed the shore supply capacity.

✓ Verified Model Answer (Text Solution)