Industrial Hazards – Electrical MCQs With Answer

Industrial Hazards – Electrical MCQs With Answer

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Introduction

Industrial Hazards – Electrical MCQs With Answer is designed for M.Pharm students studying MIP 202T – Scale Up & Technology Transfer. This set of questions focuses on electrical hazards commonly encountered in pharmaceutical manufacturing and pilot plants, highlighting practical control measures such as earthing, bonding, isolation, RCD use, PPE, lockout–tagout and safe work procedures. The quiz emphasizes application of safety principles during equipment installation, maintenance and scale-up activities, helping students recognize risks that can cause shock, burns, arc flash or ignition of solvents. Answers include concise correct choices to reinforce learning and support safe design and transfer of pharmaceutical processes.

Q1. Which of the following is the primary immediate hazard to personnel from an electrical fault in a pharmaceutical plant?

  • Exposure to toxic gases
  • Electric shock
  • Slip and fall
  • Chemical burns

Correct Answer: Electric shock

Q2. What is the main purpose of earthing (grounding) electrical equipment in a manufacturing facility?

  • To increase equipment operating voltage
  • To protect against mechanical failure
  • To provide a low-resistance path for fault current to reduce shock and fire risk
  • To prevent electromagnetic interference only

Correct Answer: To provide a low-resistance path for fault current to reduce shock and fire risk

Q3. Which device is specifically designed to detect earth leakage current and disconnect supply to protect people?

  • Circuit breaker (MCB)
  • Residual Current Device (RCD)
  • Surge protector
  • Auto-transformer

Correct Answer: Residual Current Device (RCD)

Q4. For controlling static electricity during handling of flammable solvents in scale-up, the most appropriate practice is:

  • Increasing room humidity only
  • Using insulated tools to avoid conductivity
  • Bonding and grounding conductive containers and equipment
  • Unplugging all electronic equipment

Correct Answer: Bonding and grounding conductive containers and equipment

Q5. What is the typical sensitivity (trip current) recommended for RCDs used for personnel protection?

  • 1 A
  • 300 mA
  • 30 mA
  • 10 A

Correct Answer: 30 mA

Q6. Which one of the following best describes “lockout–tagout” (LOTO) in electrical maintenance?

  • Temporarily turning off equipment without documenting
  • Isolating and physically securing energy sources and labelling them to prevent re-energization during maintenance
  • Using a lock to secure toolboxes
  • Tagging defective products for rework

Correct Answer: Isolating and physically securing energy sources and labelling them to prevent re-energization during maintenance

Q7. Which statement correctly contrasts earthing (grounding) and bonding?

  • Earthing connects conductive parts together; bonding connects to the earth
  • Bonding is insulation of conductors; earthing is mechanical protection
  • Earthing connects equipment to earth; bonding connects conductive parts together to equalize potential
  • They are identical and interchangeable terms

Correct Answer: Earthing connects equipment to earth; bonding connects conductive parts together to equalize potential

Q8. Which instrument is typically used to test the insulation resistance of motor windings and cable insulation?

  • Thermal camera
  • Multimeter on continuity mode
  • Insulation resistance tester (megger)
  • Clamp meter measuring current only

Correct Answer: Insulation resistance tester (megger)

Q9. What is the most immediate danger to personnel during an arc flash incident?

  • Radiation exposure from neutrons
  • Thermal burns and blast pressure
  • Long-term hearing loss only
  • Slow chemical poisoning

Correct Answer: Thermal burns and blast pressure

Q10. In hazardous area classification for flammable vapors, which zone describes an area where an explosive atmosphere is likely to occur in normal operation?

  • Zone 2
  • Zone 1
  • Zone 0
  • Non-hazardous area

Correct Answer: Zone 1

Q11. Which of the following is a correct characteristic of double-insulated (Class II) electrical equipment used in laboratories?

  • It requires a protective earth connection
  • It has basic insulation only
  • It provides two layers of insulation so no protective earth is required
  • It must always be used with an RCD of 300 mA

Correct Answer: It provides two layers of insulation so no protective earth is required

Q12. Which color coding is commonly used for protective earth (PE) conductors in modern international practice?

  • Black
  • Blue
  • Green-yellow
  • Red

Correct Answer: Green-yellow

Q13. Which current magnitude is most likely to induce ventricular fibrillation in an average adult under AC exposure?

  • 0.5 mA
  • 10 mA
  • 100 mA
  • 5 A

Correct Answer: 100 mA

Q14. What is a recommended safe work practice before starting electrical maintenance on a motor control panel?

  • Put on casual gloves and start work
  • Rely on colleagues to remember to switch off equipment
  • Verify isolation by testing for absence of voltage after isolating and locking out
  • Idle the equipment for five minutes and begin

Correct Answer: Verify isolation by testing for absence of voltage after isolating and locking out

Q15. Which method is commonly used to measure the resistance of a plant earthing system accurately?

  • Meggering live conductors
  • Three-point fall-of-potential (earth resistance) test
  • Measuring voltage drop under load only
  • Visual inspection of earth rod paint

Correct Answer: Three-point fall-of-potential (earth resistance) test

Q16. For preventing ignition of solvent vapors in a filling line, which engineering control is most effective?

  • Administrative training only
  • Explosion-proof (intrinsically safe) electrical equipment and proper bonding/earthing
  • Using nonconductive plastic drums without bonding
  • Wearing cotton lab coats

Correct Answer: Explosion-proof (intrinsically safe) electrical equipment and proper bonding/earthing

Q17. Which personal protective equipment is specifically rated for arc flash work?

  • Ordinary leather gloves and cotton shirt
  • Arc-rated clothing, face shield and insulating gloves
  • Plastic apron and safety glasses only
  • Disposable nitrile gloves only

Correct Answer: Arc-rated clothing, face shield and insulating gloves

Q18. Which condition in electrical distribution systems most commonly causes overheating and potential fire hazards detectable by thermal imaging?

  • Balanced loads on all phases
  • Loose or corroded connections causing high contact resistance
  • Correctly sized cables
  • Properly torqued terminal screws

Correct Answer: Loose or corroded connections causing high contact resistance

Q19. When selecting a residual current device (RCD) for wet-area protection near process tanks, which feature is most important?

  • High trip current above 500 mA
  • Appropriate sensitivity (e.g., 30 mA) and suitable environmental ingress protection
  • Only magnetic trip characteristic
  • RCDs are never recommended in wet areas

Correct Answer: Appropriate sensitivity (e.g., 30 mA) and suitable environmental ingress protection

Q20. During scale-up of electrical drive equipment for a reactor agitator, which consideration is most critical to reduce electrical hazard risk?

  • Choosing the most compact motor regardless of duty
  • Specifying correct motor enclosure, overload protection, proper earthing and safe isolation facilities
  • Using the cheapest available starter
  • Ignoring transient currents during startup

Correct Answer: Specifying correct motor enclosure, overload protection, proper earthing and safe isolation facilities

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