Skip to content
DG Exit Exam
Home
Answer Key

HV exit exam questions and answers — Set 2

Set 2 of the High Voltage Safety Officer & Switchgear Operations (HV) exit exam bank — 30 of 193 questions, with the correct option marked and a one-line explanation for every one. Read it end to end, jump to a single set, or search it — then sit the same bank as a timed paper. The real DG Shipping exit exam is 30 marks with 15 to pass.

These are the bank's original groupings. Practising deals the whole bank out again every time you reshuffle, so a practice “Set 3” is a different 30 questions each time — the set numbers below are the source file's, and are only used here so the key stays navigable. Options are listed in their original order with fixed letters; when you practise, those move too.

Bank last rebuilt .

Practise these HV questions HV mock exit exam, 30 marks HV exit exam sets and syllabus

30 of 30 shown · Set 2

Nothing in this set matches that. Try a shorter word, or search the whole key.

Set 2 — 30 HV exit exam questions with answers

1. What is the function of a Synchroscope on an HV switchboard during generator paralleling?

  • A. Test insulation
  • B. Measure fuel
  • C. Indicate phase angle alignment and frequency difference between incoming generator and live busbar
  • D. Measure oil pressure
Answer: C — Indicate phase angle alignment and frequency difference between incoming generator and live busbar
Synchroscopes rotate to show when incoming generator frequency and phase match busbars for safe breaker closing.

2. What risk occurs if a generator breaker is closed out of phase (e.g. 180° out of phase) with live HV busbar?

  • A. Engine stops
  • B. Severe mechanical torque shock shearing generator shaft, massive fault current, and switchboard explosion
  • C. Slight light dim
  • D. Smooth speed up
Answer: B — Severe mechanical torque shock shearing generator shaft, massive fault current, and switchboard explosion
Out-of-phase paralleling generates massive mechanical and magnetic forces that can destroy engine mounts and switchgear.

3. What is an HV Competent Person (HVCP) under marine safety management systems?

  • A. Steward
  • B. Person trained and authorized to perform specific HV work under supervision of an HV Authorised Person
  • C. Any crew member
  • D. Deck apprentice
Answer: B — Person trained and authorized to perform specific HV work under supervision of an HV Authorised Person
Competent Persons have verified practical training to carry out specified HV switching or maintenance tasks safely.

4. What publication provides detailed rules for Electrical Installations on Ships including High Voltage (IEC 60092)?

  • A. IMDG Code
  • B. MARPOL Annex VI
  • C. IEC 60092 Standards / SOLAS Chapter II-1
  • D. STCW Table A-II/1
Answer: C — IEC 60092 Standards / SOLAS Chapter II-1
IEC 60092 series is the global engineering standard for marine electrical design, HV equipment, and safety.

5. How frequently must operational drills and practical checks for regulatory compliance and STCW code requirements be conducted for High Voltage Safety & Switchgear?

  • A. Only when requested by port State control inspectors
  • B. At least monthly or as mandated by SOLAS and shipboard safety management system (SMS)
  • C. Annually prior to vessel drydocking
  • D. Once every 5 years during special survey
Answer: B — At least monthly or as mandated by SOLAS and shipboard safety management system (SMS)
Regular drills maintain crew emergency readiness and satisfy SOLAS requirements.

6. What documented record must be maintained on board following completion of tasks related to regulatory compliance and STCW code requirements in High Voltage Safety & Switchgear?

  • A. No written record is required
  • B. Entry in the official Deck or Engine Logbook recording date, time, and operational parameters
  • C. Verbal update to port agent without logging
  • D. Unsigned note on the shipboard notice board
Answer: B — Entry in the official Deck or Engine Logbook recording date, time, and operational parameters
Official logbook entries provide mandatory legal documentation of shipboard safety tasks.

7. What safety enclosure rating (IP Rating) is required for High Voltage marine switchboard cubicles?

  • A. IP00
  • B. IP10
  • C. No rating
  • D. IP2X minimum (protection against touch) up to IP44/IP54 for splash protection
Answer: D — IP2X minimum (protection against touch) up to IP44/IP54 for splash protection
IP ratings prevent accidental tool or finger contact with live HV busbars.

8. What is the function of a High Voltage bus tie breaker?

  • A. Ties ropes
  • B. Connects or isolates two separate HV busbar sections for operational flexibility and redundancy
  • C. Connects battery charger
  • D. Regulates water
Answer: B — Connects or isolates two separate HV busbar sections for operational flexibility and redundancy
Bus tie breakers allow split-busbar operation so a fault on one side does not shut down the entire ship.

9. What device measures temperature continuously inside HV motor or generator stator windings?

  • A. Pressure gauge
  • B. Glass thermometer
  • C. Resistance Temperature Detectors (RTD - PT100) or Thermocouples
  • D. Hydrometer
Answer: C — Resistance Temperature Detectors (RTD - PT100) or Thermocouples
Embedded PT100 RTDs trigger alarm and trip signals if winding insulation temperature exceeds limits.

10. What procedure is followed during Sanction to Test on High Voltage equipment?

  • A. Temporarily remove safety earths under strict control to perform insulation or hi-pot testing, then re-earth
  • B. Remove warning signs
  • C. Turn on generator full load
  • D. Cancel permit
Answer: A — Temporarily remove safety earths under strict control to perform insulation or hi-pot testing, then re-earth
Sanction to Test allows controlled temporary removal of earths for insulation diagnostics.

11. What is High Potential (Hi-Pot) dielectric testing on HV cables?

  • A. Testing battery with bulb
  • B. Applying elevated DC/AC voltage (e.g. 2x rated voltage) to verify cable dielectric withstand strength
  • C. Measuring length
  • D. Checking cable color
Answer: B — Applying elevated DC/AC voltage (e.g. 2x rated voltage) to verify cable dielectric withstand strength
Hi-Pot testing proves that cable insulation can withstand over-voltage surges without breakdown.

12. What is the function of a surge arrestor connected to HV generator terminals?

  • A. Cool generator
  • B. Reduce noise
  • C. Divert high-voltage switching surges and lightning spikes safely to ground
  • D. Increase generator power
Answer: C — Divert high-voltage switching surges and lightning spikes safely to ground
Surge arrestors clamp fast transient voltage spikes, protecting expensive stator insulation.

13. What risk occurs if an HV circuit breaker is closed into a solid phase-to-phase short circuit fault?

  • A. Massive fault current flows; instantaneous overcurrent relays must trip breaker within cycles
  • B. Heats up slowly over hours
  • C. Voltage increases smoothly
  • D. Speed increases
Answer: A — Massive fault current flows; instantaneous overcurrent relays must trip breaker within cycles
Fault currents reach tens of thousands of Amperes; fast electromagnetic tripping clears the short circuit instantly.

14. What safety floor matting must be placed in front of marine High Voltage switchboards?

  • A. Aluminum plate
  • B. Steel mesh mat
  • C. Wet cloth rag
  • D. Tested dielectric insulating rubber matting (rated for operating voltage, e.g. 15 kV - 30 kV rating)
Answer: D — Tested dielectric insulating rubber matting (rated for operating voltage, e.g. 15 kV - 30 kV rating)
Certified insulating rubber mats provide secondary shock protection for operators standing at switchboards.

15. What type of fire extinguisher is mandatory near High Voltage switchboard rooms?

  • A. Foam pipe
  • B. Water jet
  • C. Carbon Dioxide (CO2) or Clean Agent non-conducting gas extinguishers
  • D. Saltwater hose
Answer: C — Carbon Dioxide (CO2) or Clean Agent non-conducting gas extinguishers
CO2 and clean gas agents extinguish electrical fires without leaving conductive or corrosive residue.

16. Who keeps primary key to safety padlocks securing an HV isolation point under a Permit to Work?

  • A. Messman
  • B. Anyone on deck
  • C. Pilot
  • D. The High Voltage Authorised Person (HVAP) / Person in Charge of work
Answer: D — The High Voltage Authorised Person (HVAP) / Person in Charge of work
Key control ensures no unauthorized person can remove padlocks or re-energize equipment during maintenance.

17. What type of personal protective equipment (PPE) is essential when handling regulatory compliance and STCW code requirements under High Voltage Safety & Switchgear guidelines?

  • A. Standard street clothing with rubber gloves
  • B. Basic cotton coveralls without eye or foot protection
  • C. Certified task-specific PPE meeting SOLAS/IMO performance standards
  • D. High-visibility vest only
Answer: C — Certified task-specific PPE meeting SOLAS/IMO performance standards
Approved PPE protects personnel against specific physical and chemical hazards.

18. What parameter must be verified prior to authorizing enclosed space entry for regulatory compliance and STCW code requirements related to High Voltage Safety & Switchgear?

  • A. Visual inspection through access hatch without gas testing
  • B. Temperature check only
  • C. Oxygen level at 15% with ventilation turned off
  • D. Atmospheric oxygen level at 20.9% and zero toxic/flammable gas concentration
Answer: D — Atmospheric oxygen level at 20.9% and zero toxic/flammable gas concentration
Enclosed space safety requires verified atmospheric gas testing prior to entry.

19. What is the function of a zero-sequence current transformer (ZSCT) in core-balance earth fault protection?

  • A. Control temp
  • B. Measure RPM
  • C. Detect vector sum of 3-phase currents; any non-zero value indicates earth leakage current
  • D. Measure battery
Answer: C — Detect vector sum of 3-phase currents; any non-zero value indicates earth leakage current
ZSCTs enclose all three phase cables; balanced current sums to zero, whereas earth leakage produces unbalance output.

20. What is the effect of harmonics generated by large High Voltage variable frequency drives (VFD)?

  • A. Cleans contacts
  • B. Reduces cable size
  • C. Increases efficiency 50%
  • D. Voltage waveform distortion, overheating of transformers/generators, and electronic interference
Answer: D — Voltage waveform distortion, overheating of transformers/generators, and electronic interference
VFD switching generates high-frequency harmonic currents requiring active/passive harmonic filters.

21. What maintenance step is required before cleaning HV switchboard busbar compartments?

  • A. Complete isolation, prove dead, apply portable earths, post warning signs, and issue HV PTW
  • B. Spray solvent live
  • C. Blow compressed air live
  • D. Wipe live with damp cloth
Answer: A — Complete isolation, prove dead, apply portable earths, post warning signs, and issue HV PTW
Busbar compartments MUST be totally de-energized, tested dead, earthed, and permitted before opening panels.

22. What is the function of an Automatic Voltage Regulator (AVR) on an HV generator?

  • A. Control generator field excitation to maintain steady terminal voltage under changing load
  • B. Measure oil pressure
  • C. Cool bearings
  • D. Control engine RPM
Answer: A — Control generator field excitation to maintain steady terminal voltage under changing load
AVRs adjust rotor field current to keep generated voltage stable despite load swings.

23. What is the purpose of an anti-condensation heater fitted inside HV electric motors and switchboards?

  • A. Heat engine room
  • B. Warm lube oil
  • C. Dry clothes
  • D. Maintain internal temperature slightly above ambient when stopped to prevent moisture condensation
Answer: D — Maintain internal temperature slightly above ambient when stopped to prevent moisture condensation
Anti-condensation space heaters energize automatically when equipment stops, keeping internal air dry.

24. What safety precaution must be observed when using a high voltage test probe to prove equipment dead?

  • A. Use low voltage light
  • B. Test probe on known live source FIRST, test target equipment, then re-test probe on known live source ('Live-Dead-Live' test)
  • C. Test on table
  • D. Assume indicator works
Answer: B — Test probe on known live source FIRST, test target equipment, then re-test probe on known live source ('Live-Dead-Live' test)
The 'Live-Dead-Live' protocol proves the voltage detector itself was working before and after the test.

25. What device trips an HV transformer if gas accumulation or oil surge occurs due to internal fault?

  • A. Speed governor
  • B. Thermocouple
  • C. Buchholz Relay
  • D. Reverse power relay
Answer: C — Buchholz Relay
Buchholz relays mounted on oil-immersed transformers detect internal arcing gas bubbles and oil surges.

26. What is the purpose of Lockout / Tagout (LOTO) padlocks on HV isolators?

  • A. Prevent theft
  • B. Hold door open
  • C. Decorate panel
  • D. Physically lock isolator handles in OPEN/OFF position with warning tags so no one can re-energize circuit
Answer: D — Physically lock isolator handles in OPEN/OFF position with warning tags so no one can re-energize circuit
LOTO padlocks prevent accidental or unauthorized re-closure of isolation switches.

27. What action must be taken immediately if a colleague contacts a High Voltage live conductor and collapses?

  • A. Throw water
  • B. Grab victim's arm bare hands
  • C. Run away
  • D. DO NOT touch victim directly; isolate HV power source immediately or use certified HV insulating rescue hook to pull victim away, then call emergency CPR
Answer: D — DO NOT touch victim directly; isolate HV power source immediately or use certified HV insulating rescue hook to pull victim away, then call emergency CPR
Touching an HV casualty before isolating power turns the rescuer into a second high-voltage casualty.

28. Who has overall responsibility for enforcing High Voltage safety management systems on board?

  • A. Ship cook
  • B. Port Agent
  • C. Shore electrician
  • D. The Chief Engineer and Ship's Master
Answer: D — The Chief Engineer and Ship's Master
The Chief Engineer leads technical HV management while the Master maintains overall safety responsibility.

29. What key responsibility belongs to seafarers performing watchkeeping duties for regulatory compliance and STCW code requirements under High Voltage Safety & Switchgear?

  • A. Continuous monitoring of operational parameters and immediate reporting of anomalies
  • B. Operating equipment beyond design pressure limits
  • C. Bypassing safety trips during routine operations
  • D. Leaving watchkeeping station unattended
Answer: A — Continuous monitoring of operational parameters and immediate reporting of anomalies
Continuous vigilance and prompt communication are core watchkeeping duties under STCW.

30. Which document contains detailed hazard data and emergency handling instructions for substances involved in regulatory compliance and STCW code requirements during High Voltage Safety & Switchgear?

  • A. Bill of Lading description
  • B. Crew List document
  • C. Safety Data Sheet (SDS) / Material Safety Data Sheet (MSDS)
  • D. Ship's Cargo Manifest summary page
Answer: C — Safety Data Sheet (SDS) / Material Safety Data Sheet (MSDS)
Safety Data Sheets provide critical hazard identification, PPE requirements, and first aid response steps.

Printing this? Use your browser's Print (Ctrl/⌘ + P) — the buttons, the search box and the site chrome drop out and the questions run on as plain text, so a set fits a few pages. Filter to one set first if you only want that set on paper.

Practise these HV questions as a timed paper All 193 HV questions and answers HV exit exam sets and syllabus All 27 STCW exit exam courses