33 LV Design & Panels questions from the Electrical Design bank, written for Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd.
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A.kVA from load watts over power factor with 20–25% margin, battery Ah from watts times backup hours over DC volts, efficiency and depth of discharge
B.power control centre distributes the incoming supply through ACBs and MCCBs, while a motor control centre houses starters for individual motors
C.free lighting design software that uses luminaire IES/LDT photometry to compute illuminance, uniformity and UGR against IS 3646 or EN 12464 targets
D.only the breaker nearest the fault trips, achieved by current, time or zone-selective interlocking and verified with manufacturer selectivity tables
Answer + AI explanation with Pro
2. Which term means: "power control centre distributes the incoming supply through ACBs and MCCBs, while a motor control centre houses starters for individual motors"?
Junior
A.DIALux
B.PCC vs MCC
C.Forms of separation
D.Panel temperature-rise limits
Answer + AI explanation with Pro
3. Which statement is correct?
Junior
A.PCC vs MCC — kVA from load watts over power factor with 20–25% margin, battery Ah from watts times backup hours over DC volts, efficiency and depth of discharge
B.PCC vs MCC — only the breaker nearest the fault trips, achieved by current, time or zone-selective interlocking and verified with manufacturer selectivity tables
C.PCC vs MCC — MCB to 125 A and 10 kA per IEC 60898, MCCB 16–1600 A up to 100 kA with adjustable trips, ACB 630–6300 A drawout with full electronic protection
D.PCC vs MCC — power control centre distributes the incoming supply through ACBs and MCCBs, while a motor control centre houses starters for individual motors
Answer + AI explanation with Pro
4. What is MCB vs MCCB vs ACB?
Junior
A.IEC 61439-1 allows 70 K at terminals for external conductors and 30–40 K on accessible enclosure surfaces, proved by test or calculation
B.only the breaker nearest the fault trips, achieved by current, time or zone-selective interlocking and verified with manufacturer selectivity tables
C.rating from running load kW and power factor plus the largest motor's starting kVA, with step loading limited to about 50–60% of rating per step
D.MCB to 125 A and 10 kA per IEC 60898, MCCB 16–1600 A up to 100 kA with adjustable trips, ACB 630–6300 A drawout with full electronic protection
Answer + AI explanation with Pro
5. Which term means: "MCB to 125 A and 10 kA per IEC 60898, MCCB 16–1600 A up to 100 kA with adjustable trips, ACB 630–6300 A drawout with full electronic protection"?
Junior
A.MCB vs MCCB vs ACB
B.Panel temperature-rise limits
C.Icu vs Ics
D.Forms of separation
Answer + AI explanation with Pro
6. Which statement is correct?
Junior
A.MCB vs MCCB vs ACB — ultimate breaking capacity proved by an O-CO sequence versus service breaking capacity proved by O-CO-CO after which the breaker must still carry rated current
B.MCB vs MCCB vs ACB — MCB to 125 A and 10 kA per IEC 60898, MCCB 16–1600 A up to 100 kA with adjustable trips, ACB 630–6300 A drawout with full electronic protection
C.MCB vs MCCB vs ACB — kVA from load watts over power factor with 20–25% margin, battery Ah from watts times backup hours over DC volts, efficiency and depth of discharge
D.MCB vs MCCB vs ACB — only the breaker nearest the fault trips, achieved by current, time or zone-selective interlocking and verified with manufacturer selectivity tables
Answer + AI explanation with Pro
7. What is DIALux?
Junior
A.IEC 61439 Form 1 has no separation, Form 2 separates busbars from units, Form 3 units from each other, Form 4 also separates terminals
B.ultimate breaking capacity proved by an O-CO sequence versus service breaking capacity proved by O-CO-CO after which the breaker must still carry rated current
C.MCB to 125 A and 10 kA per IEC 60898, MCCB 16–1600 A up to 100 kA with adjustable trips, ACB 630–6300 A drawout with full electronic protection
D.free lighting design software that uses luminaire IES/LDT photometry to compute illuminance, uniformity and UGR against IS 3646 or EN 12464 targets
Answer + AI explanation with Pro
8. Which term means: "free lighting design software that uses luminaire IES/LDT photometry to compute illuminance, uniformity and UGR against IS 3646 or EN 12464 targets"?
Junior
A.Panel temperature-rise limits
B.DIALux
C.PCC vs MCC
D.Type-2 coordination
Answer + AI explanation with Pro
9. Which statement is correct?
Junior
A.DIALux — power control centre distributes the incoming supply through ACBs and MCCBs, while a motor control centre houses starters for individual motors
B.DIALux — IEC 61439 Form 1 has no separation, Form 2 separates busbars from units, Form 3 units from each other, Form 4 also separates terminals
C.DIALux — free lighting design software that uses luminaire IES/LDT photometry to compute illuminance, uniformity and UGR against IS 3646 or EN 12464 targets
D.DIALux — kVA from load watts over power factor with 20–25% margin, battery Ah from watts times backup hours over DC volts, efficiency and depth of discharge
Answer + AI explanation with Pro
10. What is Forms of separation?
Mid
A.IEC 61439 Form 1 has no separation, Form 2 separates busbars from units, Form 3 units from each other, Form 4 also separates terminals
B.MCB to 125 A and 10 kA per IEC 60898, MCCB 16–1600 A up to 100 kA with adjustable trips, ACB 630–6300 A drawout with full electronic protection
C.IEC 60947-4-1 requirement that after a short circuit the starter remains usable with no damage beyond light contact welding that is easily separated
D.kVA from load watts over power factor with 20–25% margin, battery Ah from watts times backup hours over DC volts, efficiency and depth of discharge
Answer + AI explanation with Pro
11. Which term means: "IEC 61439 Form 1 has no separation, Form 2 separates busbars from units, Form 3 units from each other, Form 4 also separates terminals"?
Mid
A.DG set sizing
B.Discrimination
C.Forms of separation
D.Type-2 coordination
Answer + AI explanation with Pro
12. Which statement is correct?
Mid
A.Forms of separation — IEC 61439 Form 1 has no separation, Form 2 separates busbars from units, Form 3 units from each other, Form 4 also separates terminals
B.Forms of separation — MCB to 125 A and 10 kA per IEC 60898, MCCB 16–1600 A up to 100 kA with adjustable trips, ACB 630–6300 A drawout with full electronic protection
C.Forms of separation — free lighting design software that uses luminaire IES/LDT photometry to compute illuminance, uniformity and UGR against IS 3646 or EN 12464 targets
D.Forms of separation — only the breaker nearest the fault trips, achieved by current, time or zone-selective interlocking and verified with manufacturer selectivity tables
Answer + AI explanation with Pro
13. What is Type-2 coordination?
Mid
A.IEC 61439-1 allows 70 K at terminals for external conductors and 30–40 K on accessible enclosure surfaces, proved by test or calculation
B.MCB to 125 A and 10 kA per IEC 60898, MCCB 16–1600 A up to 100 kA with adjustable trips, ACB 630–6300 A drawout with full electronic protection
C.IEC 61439 factor applied to outgoing circuits loaded together, such as 0.8 for 4–5 circuits and 0.6 for 10 or more
D.IEC 60947-4-1 requirement that after a short circuit the starter remains usable with no damage beyond light contact welding that is easily separated
Answer + AI explanation with Pro
14. Which term means: "IEC 60947-4-1 requirement that after a short circuit the starter remains usable with no damage beyond light contact welding that is easily separated"?
Mid
A.Rated diversity factor
B.DIALux
C.Discrimination
D.Type-2 coordination
Answer + AI explanation with Pro
15. Which statement is correct?
Mid
A.Type-2 coordination — IEC 61439-1 allows 70 K at terminals for external conductors and 30–40 K on accessible enclosure surfaces, proved by test or calculation
B.Type-2 coordination — IEC 60947-4-1 requirement that after a short circuit the starter remains usable with no damage beyond light contact welding that is easily separated
C.Type-2 coordination — IEC 61439 factor applied to outgoing circuits loaded together, such as 0.8 for 4–5 circuits and 0.6 for 10 or more
D.Type-2 coordination — only the breaker nearest the fault trips, achieved by current, time or zone-selective interlocking and verified with manufacturer selectivity tables
Answer + AI explanation with Pro
16. What is Discrimination?
Mid
A.only the breaker nearest the fault trips, achieved by current, time or zone-selective interlocking and verified with manufacturer selectivity tables
B.IEC 60947-4-1 requirement that after a short circuit the starter remains usable with no damage beyond light contact welding that is easily separated
C.kVA from load watts over power factor with 20–25% margin, battery Ah from watts times backup hours over DC volts, efficiency and depth of discharge
D.power control centre distributes the incoming supply through ACBs and MCCBs, while a motor control centre houses starters for individual motors
Answer + AI explanation with Pro
17. Which term means: "only the breaker nearest the fault trips, achieved by current, time or zone-selective interlocking and verified with manufacturer selectivity tables"?
Mid
A.Discrimination
B.Rated diversity factor
C.DG set sizing
D.Type-2 coordination
Answer + AI explanation with Pro
18. Which statement is correct?
Mid
A.Discrimination — only the breaker nearest the fault trips, achieved by current, time or zone-selective interlocking and verified with manufacturer selectivity tables
B.Discrimination — IEC 60947-4-1 requirement that after a short circuit the starter remains usable with no damage beyond light contact welding that is easily separated
C.Discrimination — MCB to 125 A and 10 kA per IEC 60898, MCCB 16–1600 A up to 100 kA with adjustable trips, ACB 630–6300 A drawout with full electronic protection
D.Discrimination — power control centre distributes the incoming supply through ACBs and MCCBs, while a motor control centre houses starters for individual motors
Answer + AI explanation with Pro
19. What is Icu vs Ics?
Mid
A.free lighting design software that uses luminaire IES/LDT photometry to compute illuminance, uniformity and UGR against IS 3646 or EN 12464 targets
B.MCB to 125 A and 10 kA per IEC 60898, MCCB 16–1600 A up to 100 kA with adjustable trips, ACB 630–6300 A drawout with full electronic protection
C.kVA from load watts over power factor with 20–25% margin, battery Ah from watts times backup hours over DC volts, efficiency and depth of discharge
D.ultimate breaking capacity proved by an O-CO sequence versus service breaking capacity proved by O-CO-CO after which the breaker must still carry rated current
Answer + AI explanation with Pro
20. Which term means: "ultimate breaking capacity proved by an O-CO sequence versus service breaking capacity proved by O-CO-CO after which the breaker must still carry rated current"?
Mid
A.DG set sizing
B.Panel temperature-rise limits
C.Discrimination
D.Icu vs Ics
Answer + AI explanation with Pro
21. Which statement is correct?
Mid
A.Icu vs Ics — kVA from load watts over power factor with 20–25% margin, battery Ah from watts times backup hours over DC volts, efficiency and depth of discharge
B.Icu vs Ics — only the breaker nearest the fault trips, achieved by current, time or zone-selective interlocking and verified with manufacturer selectivity tables
C.Icu vs Ics — ultimate breaking capacity proved by an O-CO sequence versus service breaking capacity proved by O-CO-CO after which the breaker must still carry rated current
D.Icu vs Ics — IEC 60947-4-1 requirement that after a short circuit the starter remains usable with no damage beyond light contact welding that is easily separated
Answer + AI explanation with Pro
22. What is DG set sizing?
Mid
A.rating from running load kW and power factor plus the largest motor's starting kVA, with step loading limited to about 50–60% of rating per step
B.IEC 60947-4-1 requirement that after a short circuit the starter remains usable with no damage beyond light contact welding that is easily separated
C.power control centre distributes the incoming supply through ACBs and MCCBs, while a motor control centre houses starters for individual motors
D.only the breaker nearest the fault trips, achieved by current, time or zone-selective interlocking and verified with manufacturer selectivity tables
Answer + AI explanation with Pro
23. Which term means: "rating from running load kW and power factor plus the largest motor's starting kVA, with step loading limited to about 50–60% of rating per step"?
Mid
A.DG set sizing
B.PCC vs MCC
C.UPS sizing
D.Discrimination
Answer + AI explanation with Pro
24. Which statement is correct?
Mid
A.DG set sizing — MCB to 125 A and 10 kA per IEC 60898, MCCB 16–1600 A up to 100 kA with adjustable trips, ACB 630–6300 A drawout with full electronic protection
B.DG set sizing — IEC 61439 Form 1 has no separation, Form 2 separates busbars from units, Form 3 units from each other, Form 4 also separates terminals
C.DG set sizing — only the breaker nearest the fault trips, achieved by current, time or zone-selective interlocking and verified with manufacturer selectivity tables
D.DG set sizing — rating from running load kW and power factor plus the largest motor's starting kVA, with step loading limited to about 50–60% of rating per step
Answer + AI explanation with Pro
25. What is UPS sizing?
Mid
A.MCB to 125 A and 10 kA per IEC 60898, MCCB 16–1600 A up to 100 kA with adjustable trips, ACB 630–6300 A drawout with full electronic protection
B.kVA from load watts over power factor with 20–25% margin, battery Ah from watts times backup hours over DC volts, efficiency and depth of discharge
C.IEC 60947-4-1 requirement that after a short circuit the starter remains usable with no damage beyond light contact welding that is easily separated
D.only the breaker nearest the fault trips, achieved by current, time or zone-selective interlocking and verified with manufacturer selectivity tables
Answer + AI explanation with Pro
26. Which term means: "kVA from load watts over power factor with 20–25% margin, battery Ah from watts times backup hours over DC volts, efficiency and depth of discharge"?
Mid
A.UPS sizing
B.Discrimination
C.Icu vs Ics
D.Forms of separation
Answer + AI explanation with Pro
27. Which statement is correct?
Mid
A.UPS sizing — IEC 61439-1 allows 70 K at terminals for external conductors and 30–40 K on accessible enclosure surfaces, proved by test or calculation
B.UPS sizing — free lighting design software that uses luminaire IES/LDT photometry to compute illuminance, uniformity and UGR against IS 3646 or EN 12464 targets
C.UPS sizing — kVA from load watts over power factor with 20–25% margin, battery Ah from watts times backup hours over DC volts, efficiency and depth of discharge
D.UPS sizing — rating from running load kW and power factor plus the largest motor's starting kVA, with step loading limited to about 50–60% of rating per step
Answer + AI explanation with Pro
28. What is Rated diversity factor?
Senior
A.IEC 61439-1 allows 70 K at terminals for external conductors and 30–40 K on accessible enclosure surfaces, proved by test or calculation
B.free lighting design software that uses luminaire IES/LDT photometry to compute illuminance, uniformity and UGR against IS 3646 or EN 12464 targets
C.kVA from load watts over power factor with 20–25% margin, battery Ah from watts times backup hours over DC volts, efficiency and depth of discharge
D.IEC 61439 factor applied to outgoing circuits loaded together, such as 0.8 for 4–5 circuits and 0.6 for 10 or more
Answer + AI explanation with Pro
29. Which term means: "IEC 61439 factor applied to outgoing circuits loaded together, such as 0.8 for 4–5 circuits and 0.6 for 10 or more"?
Senior
A.DG set sizing
B.PCC vs MCC
C.Rated diversity factor
D.DIALux
Answer + AI explanation with Pro
30. Which statement is correct?
Senior
A.Rated diversity factor — IEC 61439 factor applied to outgoing circuits loaded together, such as 0.8 for 4–5 circuits and 0.6 for 10 or more
B.Rated diversity factor — IEC 61439-1 allows 70 K at terminals for external conductors and 30–40 K on accessible enclosure surfaces, proved by test or calculation
C.Rated diversity factor — power control centre distributes the incoming supply through ACBs and MCCBs, while a motor control centre houses starters for individual motors
D.Rated diversity factor — kVA from load watts over power factor with 20–25% margin, battery Ah from watts times backup hours over DC volts, efficiency and depth of discharge
Answer + AI explanation with Pro
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