Question 1

The terms interrupting rating and are used interchangeably in the electrical industry, but there is a subtle difference.

Accepted Answer

A)  short-circuit rating
B)  interrupting minimum
C)  interrupting capacity
D)  short-circuit capacity

Question 2

What are some prohibitions on the location of overcurrent devices?

Accepted Answer

Overcurrent devices shall not:
∙ be expo...

Question 3

What is the mechanism through which thermal-magnetic circuit breakers work?

Accepted Answer

A thermal-magnetic circuit breaker conta...

Question 4

The Class fuse is a nonrenewable cartridge type and has a minimum interrupting rating of 200,000 RMS symmetrical amperes.

Accepted Answer

A)  H
B)  K
C)  R
D)  T

Question 5

Series-rated equipment is also referred to as .

Accepted Answer

A)  series-connected
B)  parallel-rated
C)  inverse-parallel
D)  series-broken

Question 6

What are peak let-through charts used for?

Accepted Answer

It is important to understand the use of...

Question 7

A dual-element, time-delay fuse has one or more fusible elements (links)  connected .

Accepted Answer

A)  in parallel
B)  in series
C)  during overload conditions
D)  every 10 seconds

Question 8

In the case of a delta, 3­phase, corner­grounded "B" phase system, a device called a can be installed in the "B" phase.

Accepted Answer

A)  service entrance
B)  switchboard
C)  cube fuse
D)  solid neutral

Question 9

Fused switches are available in ratings of up to amperes in both 250 and 600 volts.

Accepted Answer

A)  400
B)  600
C)  4000
D)  6000

Question 10

circuit breakers are the most common type in use today.

Accepted Answer

A)  Power
B)  Molded-case
C)  Air-frame
D)  Insulated-case B

Question 11

When compared to other types of fuses, the fuse has the lowest energy let-through values.

Accepted Answer

A)  dual-element, time-delay
B)  straight current-limiting
C)  dual-element, nontime-delay
D)  low-overload

Question 12

and the National Electrical Manufacturers Association establish standards for the ratings, types, classifications, and testing procedures for fuses and circuit breakers.

Accepted Answer

A)  Applied Research Laboratories, Inc.
B)  Entela, Inc.
C)  The Underwriters Laboratories, Inc.
D)  TUV Rheinland of North America, Inc. C

Question 13

Low-voltage power circuit breakers are listed under UL Standard .

Accepted Answer

A)  844
B)  1066
C)  1215
D)  1362

Question 14

Describe the class of fuses that is used for control circuit protection.

Accepted Answer

Class CC fuses are primarily used for control-circuit protection, for the protection of motor control circuits, ballasts, small transformers, and so on.They are UL listed as branch-circuit fuses.Class CC fuses are rated at 600 volts or less and have a 200,000-ampere interrupting rating in sizes from
1/10 ampere through 30 amperes.These fuses measure 1-1/2 in.x 13/32 in.(38.1 mm x 10.3 mm) and can be recognized by a button on one end of the fuse.This button is unique to Class CC fuses.When a fuseblock or fuseholder that has the matching Class CC rejection feature is installed, it is impossible to insert any other 1-1/2 in.x 13/32 in.(38.1 mm x 10.3 mm) fuse.Only a Class CC
fuse will fit intothese special fuseblocks and fuseholders.A Class CC fuse can be installed in a standard fuseholder.

Question 15

For motor branch circuits, the maximum setting of a conventional inverse-time circuit breaker must not exceed percent of the full-load current of the motor.

Accepted Answer

A)  100
B)  125
C)  200
D)  250

Question 16

Conventional plug fuses have a base referred to as a(n)  base.This base is of the same shape as the base on a light bulb.

Accepted Answer

A)  Edison
B)  Tesla
C)  filamentous
D)  threaded

Question 17

When you remove a fuse from a switch, and then take a resistance reading across the fuse using a(n)  , a good fuse will show zero or a very minimal resistance.

Accepted Answer

A)  ohmmeter
B)  wattmeter
C)  voltmeter
D)  delimiter

Question 18

An interrupting rating is a(n)  rating, which is a measure of the fuse's or circuit breaker's ability to safely open an electrical circuit under fault conditions, such as an overload, short circuit, or ground fault.

Accepted Answer

A)  recommended
B)  maximum
C)  minimum
D)  average

Question 19

Class fuses formerly were called NEC or Code fuses.

Accepted Answer

A)  H
B)  J
C)  K
D)  R

Question 20

What are the factors influencing speed of response of an overcurrent device?

Accepted Answer

The time required for the fusible elemen...

Exam 17: Overcurrent Protection: Fuses and Circuit Breakers

The terms interrupting rating and are used interchangeably in the electrical industry, but there is a subtle difference.

Correct Answer
verified

What are some prohibitions on the location of overcurrent devices?

Correct Answer
verified
Overcurrent devices shall not:
∙ be expo...
View Answer

What is the mechanism through which thermal-magnetic circuit breakers work?

Correct Answer
verified
A thermal-magnetic circuit breaker conta...
View Answer

The Class fuse is a nonrenewable cartridge type and has a minimum interrupting rating of 200,000 RMS symmetrical amperes.

Correct Answer
verified

Series-rated equipment is also referred to as .

Correct Answer
verified

What are peak let-through charts used for?

Correct Answer
verified
It is important to understand the use of...
View Answer

A dual-element, time-delay fuse has one or more fusible elements (links) connected .

Correct Answer
verified

In the case of a delta, 3phase, cornergrounded "B" phase system, a device called a can be installed in the "B" phase.

Correct Answer
verified

Fused switches are available in ratings of up to amperes in both 250 and 600 volts.

Correct Answer
verified

circuit breakers are the most common type in use today.

Correct Answer
verified
B

When compared to other types of fuses, the fuse has the lowest energy let-through values.

Correct Answer
verified

and the National Electrical Manufacturers Association establish standards for the ratings, types, classifications, and testing procedures for fuses and circuit breakers.

Correct Answer
verified
C

Low-voltage power circuit breakers are listed under UL Standard .

Correct Answer
verified

Describe the class of fuses that is used for control circuit protection.

For motor branch circuits, the maximum setting of a conventional inverse-time circuit breaker must not exceed percent of the full-load current of the motor.

Correct Answer
verified

Conventional plug fuses have a base referred to as a(n) base.This base is of the same shape as the base on a light bulb.

Correct Answer
verified

When you remove a fuse from a switch, and then take a resistance reading across the fuse using a(n) , a good fuse will show zero or a very minimal resistance.

Correct Answer
verified

An interrupting rating is a(n) rating, which is a measure of the fuse's or circuit breaker's ability to safely open an electrical circuit under fault conditions, such as an overload, short circuit, or ground fault.

Correct Answer
verified

Class fuses formerly were called NEC or Code fuses.

Correct Answer
verified

What are the factors influencing speed of response of an overcurrent device?

Correct Answer
verified
The time required for the fusible elemen...
View Answer

Exam 17: Overcurrent Protection: Fuses and Circuit Breakers

The terms interrupting rating and are used interchangeably in the electrical industry, but there is a subtle difference.

Correct AnswerverifiedShow Answer

What are some prohibitions on the location of overcurrent devices?

Correct AnswerverifiedOvercurrent devices shall not:∙ be expo...View AnswerShow Answer

What is the mechanism through which thermal-magnetic circuit breakers work?

Correct AnswerverifiedA thermal-magnetic circuit breaker conta...View AnswerShow Answer

The Class fuse is a nonrenewable cartridge type and has a minimum interrupting rating of 200,000 RMS symmetrical amperes.

Correct AnswerverifiedShow Answer

Series-rated equipment is also referred to as .

Correct AnswerverifiedShow Answer

What are peak let-through charts used for?

Correct AnswerverifiedIt is important to understand the use of...View AnswerShow Answer

A dual-element, time-delay fuse has one or more fusible elements (links) connected .

Correct AnswerverifiedShow Answer

In the case of a delta, 3­phase, corner­grounded "B" phase system, a device called a can be installed in the "B" phase.

Correct AnswerverifiedShow Answer

Fused switches are available in ratings of up to amperes in both 250 and 600 volts.

Correct AnswerverifiedShow Answer

circuit breakers are the most common type in use today.

Correct AnswerverifiedB

When compared to other types of fuses, the fuse has the lowest energy let-through values.

Correct AnswerverifiedShow Answer

and the National Electrical Manufacturers Association establish standards for the ratings, types, classifications, and testing procedures for fuses and circuit breakers.

Correct AnswerverifiedC

Low-voltage power circuit breakers are listed under UL Standard .

Correct AnswerverifiedShow Answer

Describe the class of fuses that is used for control circuit protection.

For motor branch circuits, the maximum setting of a conventional inverse-time circuit breaker must not exceed percent of the full-load current of the motor.

Correct AnswerverifiedShow Answer

Conventional plug fuses have a base referred to as a(n) base.This base is of the same shape as the base on a light bulb.

Correct AnswerverifiedShow Answer

When you remove a fuse from a switch, and then take a resistance reading across the fuse using a(n) , a good fuse will show zero or a very minimal resistance.

Correct AnswerverifiedShow Answer

An interrupting rating is a(n) rating, which is a measure of the fuse's or circuit breaker's ability to safely open an electrical circuit under fault conditions, such as an overload, short circuit, or ground fault.

Correct AnswerverifiedShow Answer

Class fuses formerly were called NEC or Code fuses.

Correct AnswerverifiedShow Answer

What are the factors influencing speed of response of an overcurrent device?

Correct AnswerverifiedThe time required for the fusible elemen...View AnswerShow Answer

Correct Answer
verified

Correct Answer
verified
Overcurrent devices shall not:
∙ be expo...
View Answer

Correct Answer
verified
A thermal-magnetic circuit breaker conta...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
It is important to understand the use of...
View Answer

Correct Answer
verified

In the case of a delta, 3phase, cornergrounded "B" phase system, a device called a can be installed in the "B" phase.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
B

Correct Answer
verified

Correct Answer
verified
C

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
The time required for the fusible elemen...
View Answer