Deck 28: Overcurrent Protectionfuses and Circuit Breakers

Question 1

A(n) ____ is a condition where a hot conductor comes into contact with a grounded surface.

A) ground fault
B) short circuit
C) overload
D) open

Answer 1

A

Question 2

With a ____ fuse, one fuse element opens quickly when a short circuit, heavy overload, or ground fault occurs, and the other element in series with the first element opens slowly on overload conditions.

A) time-delay, dual-element
B) time-delay, loaded link
C) nontime-delay
D) nontime-delay, single element

Answer 2

A

Question 3

Plug fuses shall have a(n) ____ configuration somewhere on the fuse when rated at 15 amperes or less.

A) rectangular
B) octagonal
C) square
D) hexagonal

Answer 3

D

Question 4

Circuit breakers with an interrupting rating other than ____ shall have this rating marked on the breaker.

A) 100 amperes
B) 5000 amperes
C) 10,000 amperes
D) none of the above

Question 5

The maximum ampere rating of a Type S fuse is ____.

A) 15
B) 20
C) 30
D) 60

Question 6

Cartridge fuses are available in Class H and Class R types.

Question 7

Identified handle ties are permitted to disconnect all conductors of a service as long as it takes no more than ____________________ operations of the hand to shut everything off.

Question 8

Nontime-delay fuses are not the best choice for motor circuits because of the high starting inrush current of motors.

Question 9

____ fuses are special-purpose fuses that are found in original equipment, or in commercial and industrial panelboards, multimetering equipment, and motor controllers.

A) Class BB, Class A, and Class D
B) Class CC, Class G, and Class T
C) Class G, Class UU, and Class T
D) Class CH, Class I, and Class T

Question 10

____________________ loading of a circuit is when the current flowing is within the capability of the circuit and/or the connected equipment.

Question 11

The term ____________________ refers to how long it will take a fuse or circuit breaker to open under different current values.

Question 12

A(n) ____ is a condition where the current flowing in a circuit is more than the current or equipment is designed to handle.

A) ground fault
B) short circuit
C) overload
D) open

Question 13

Current-limiting overcurrent devices will limit the amount of ____________________ by opening so fast that the full value of fault-current will not be reached

Question 14

A(n) ____________________ is a condition where the current flowing in a circuit is more than the current or equipment is designed to handle.

Question 15

A(n) ____ is a condition where two or more conductors come into contact with one another.

A) ground fault
B) short circuit
C) overload
D) open

Question 16

All new plug fuse installations shall be ____________________ fuses.

Question 17

A(n) ____________________ is a condition where two or more conductors come into contact with one another.

Question 18

Fuses are not a reliable or economical form of overcurrent protection.

Question 19

A(n) ____________________ is a condition where a hot conductor comes into contact with a grounded surface.

Question 20

Overcurrent protection for residential services, branch circuits, and feeders is provided by circuit breakers or fuses. These are the "____" of an electrical circuit.

A) life forces
B) backup
C) safety valves
D) none of the above