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1. Where are overcurrent protective devices normally installed in a branch circuit?

At the circuit load

At the supply transformer only

Where the conductors receive their supply

At circuit devices only

Question 1 of 15

2. If a 120V feeder for nonmotor loads feeds a continuous load rated at 20A and a noncontinuous load at 30A, what size overcurrent protective device should be selected?

80A

70A

45A

60A

Question 2 of 15

3. If a continuous load on a branch circuit is measured at 40A, the overcurrent protection should be sized at ________.

20A

40A

30A

50A

Question 3 of 15

4. Which of the following is true of the voltage rating of a fuse?

It can be higher than the circuit voltage but never lower.

It can be lower than the circuit voltage but never higher.

It is always the same as the circuit voltage.

It depends upon its capability to close a circuit under an overcurrent condition.

Question 4 of 15

5. Which type of fuse should be used to prevent nuisance tripping from temporary motor overloads and surge currents?

GE-base single-element fuse

Nontime-delay fuse

Edison-base plug fuse

Dual-element, time-delay fuse

Question 5 of 15

6. Types of fault current include overloads, short circuits, ground faults, and ________.

arc faults

transient faults

symmetrical faults

asymmetric faults

Question 6 of 15

7. Which of the following is within the basic scope of Underwriters Laboratories?

Functional performance of fuses

Proper selection of fuses

Safety

Reliability of fuses

Question 7 of 15

8. UL Class R fuses have a short circuit interrupting rating of up to ________.

125,000A

75,000A

50,000A

200,000A

Question 8 of 15

9. Which of the following is commonly referred to as motor branch circuit protection?

Overcurrent protection

Overvoltage protection

Component protection

Short circuit protection

Question 9 of 15

10. The branch circuit conductor and overcurrent protective device must be sized for the actual noncontinuous load plus what percentage of the continuous load?

115%

150%

125%

110%

Question 10 of 15

11. Circuit breakers are classified by ________.

color coding

manufacturer

the largest ampere rating of its range

the smallest ampere rating of its range

Question 11 of 15

12. When selecting ampere ratings of fuses and circuit breakers, the most important consideration is the ________.

size and type of load

conductor insulation

type of conductor

ambient temperature

Question 12 of 15

13. Overcurrent protection is covered in ________.

NEC Article 334

NEC Article 200

NEC Article 314

NEC Article 240

Question 13 of 15

14. What is the maximum number of circuit breakers or sets of fuses that may be used as the service disconnecting means in a main service panel without a main switch?

Question 14 of 15

15. Which of the following are designed to withstand numerous trip and reset cycles without replacement and can be thermal, magnetic, or solid-state?

Current-limiting devices

Overload relays

Semiconductor fuses

Fast-acting fuses

Question 15 of 15

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