Circuit breakers are critical components that allow the power distribution system to operate safely and reliably. As NETA Certified Technicians, we need to be familiar with the different types of circuit breakers and how they function.
1. When using a circuit breaker for isolation, what is the most effective way to lock it out?
a. Lock it in the open position.
b. Lock out the control fuses.
c. Lock it in the racked-out position.
d. Lock the high-voltage door closed.
2. Which type of insulating gas is most commonly used for high-voltage circuit breakers found in utility substations?
a. Open-air
b. Nitrogen (N2)
c. Pure oxygen (O2)
d. Sulphur hexafluoride (SF6)
3. What components do air circuit breakers contain that other breaker types do not?
a. Arc chutes
b. Wipe/wear indicators
c. Large charging springs
d. Vacuum bottles
4. Which of the following maintenance activities will help prevent breaker operating time from exceeding the manufacturer’s specifications?
a. Lubricating any moving parts
b. Circuit breaker timing test
c. Minimum open-coil pickup test
d. Wipe/wear verification
5. Racking circuit breakers is a potential source of arc flash incidents. What should be done if the breaker requires extra force when racking onto a live bus?
a. Continue to rack harder.
b. Stop and rack out.
c. Stop and leave as is.
d. Stop and get a second opinion.
6. How does breaker opening time relate to arc flash energy?
a. The breaker must open at the zero-crossing.
b. Arc flash energy is inversely proportional to breaker opening time.
c. Arc flash energy is proportional to breaker opening time.
d. Breaker opening time is not related to arc flash energy.
7. What does the term “trip-free” mean?
a. A breaker that closes with an active trip condition, then opens
b. A breaker that is free from tripping
c. A recloser that has had one trip and one reclose attempt
d. A breaker that trips with no financial implications
