HV Exit Exam • Set 1 Question 5 of 30

What medium is commonly used inside modern High Voltage marine circuit breakers for arc quenching?

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Direct Answer

Option C: Vacuum (VCB) or Sulfur Hexafluoride gas (SF6)

Vacuum Circuit Breakers (VCB) and SF6 gas breakers rapidly extinguish high-energy electrical arcs.

All Options

Water bath

Compressed oxygen

Vacuum (VCB) or Sulfur Hexafluoride gas (SF6) (Correct Answer)

Mineral oil

Detailed Explanation & Context

Vacuum Circuit Breakers (VCB) and SF6 gas breakers rapidly extinguish high-energy electrical arcs.

Relevant Framework: STCW 2010 Manila Amendments • DG Shipping E-Learning & Exit Exam Standards • High Voltage Safety Officer & Switchgear Operations (HV).

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More Questions in HV Set 1

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Q1 What voltage level is defined as High Voltage (HV) under marine SOLAS and STCW regulations? Q2 What is the primary hazard of working on High Voltage marine equipment compared to Low Voltage? Q3 What safety document MUST be issued before performing maintenance on High Voltage switchgear? Q4 What mandatory step must be taken immediately after opening an HV circuit breaker and isolator? Q5 What medium is commonly used inside modern High Voltage marine circuit breakers for arc quenching? Q6 What safety equipment must be worn when racking in or out an HV circuit breaker truck? Q7 What is the purpose of earthing switches or portable earthing leads on isolated HV equipment? Q8 What key interlock system is used to enforce strict mechanical sequence during HV switching operations? Q9 What instrument is used to measure insulation resistance of High Voltage cables and machinery? Q10 Who is authorized to issue a High Voltage Permit to Work on a ship?