Question 1

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

Accepted Answer

The Underwriters Laboratories, Inc. (often abbreviated as UL) is known for establishing safety-related certification, validation, testing, inspection, auditing, advising, and training services across a wide range of industries, including electrical safety and performance standards. UL works closely with the National Electrical Manufacturers Association (NEMA) to develop and maintain standards for electrical devices, including fuses and circuit breakers.

Question 2

What are some prohibitions on the location of overcurrent devices?

Accepted Answer

​ 
 Overcurrent devices are not permitted to: 
.be exposed to physical damage 
.be installed in the vicinity of easily ignitable material 
.be installed in clothes closets 
.be installed in bathrooms. This requirement is for dwelling units and guest rooms of hotels and motels, not for commercial and industrial buildings. 
.be installed over the steps of a stairway

Question 3

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

The National Electrical Code (NEC) allows the maximum setting of a conventional inverse-time circuit breaker for motor branch circuits to be up to 250% of the motor's full-load current.

Question 4

____ circuit breakers are the most common type in use today.

Accepted Answer

Molded-case circuit breakers are the most common type used today due to their versatility, reliability, and range of amperage ratings, making them suitable for a wide variety of applications.

Question 5

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

Accepted Answer

Straight current-limiting fuses are designed to limit the amount of energy let-through, making them have the lowest energy let-through values compared to other types of fuses.

Question 6

​What are some factors that influence speed of response of an overcurrent device?

Accepted Answer

The answer of ​What are some factors that influence speed...

Question 7

An interrupting rating is a(n)____ rating, and measures 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

The interrupting rating is a maximum rating, indicating the highest level of fault current that a fuse or circuit breaker can safely interrupt without damage or hazard.

Question 8

____ is the ability of the equipment (the entire assembly)to withstand a fault current equal to or less than the rating for the length of time it takes the specified overcurrent device to open the circuit to the equipment.

Accepted Answer

Short-circuit rating is the measure of the ability of electrical equipment to withstand a fault current up to its rated limit for a specified duration until the overcurrent protective device activates and interrupts the current.

Question 9

How do thermal-magnetic circuit breakers work?

Accepted Answer

The answer of How do thermal-magnetic circuit breakers work?...

Question 10

What is the purpose of peak let-through charts?

Accepted Answer

The answer of What is the purpose of peak let-through...

Question 11

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

An ohmmeter is used to measure resistance, and a good fuse will have very little resistance, indicating a continuous electrical path.

Question 12

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

Accepted Answer

Low-voltage power circuit breakers are listed under UL Standard 1066. This standard covers the basic requirements for low-voltage power circuit breakers used in electrical distribution systems.

Question 13

In the case of a delta, 3-phase, corner-grounded "B" phase system, a device called a ____ can be installed in the "B" phase.

Accepted Answer

The answer of In the case of a delta, 3-phase,...

Question 14

Class ____ fuses formerly were called NEC or Code fuses.

Accepted Answer

Class H fuses formerly were called NEC or Code fuses.

Question 15

Name and describe the class of fuses used for control circuit protection.

Accepted Answer

The answer of Name and describe the class of fuses...

Question 16

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

Accepted Answer

Class R fuses are nonrenewable cartridge type and have a minimum interrupting rating of 200,000 RMS symmetrical amperes.

Question 17

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

Accepted Answer

A dual-element, time-delay fuse has fusible elements connected in parallel to allow for both fast reaction to short circuits and delayed reaction to overload conditions, providing both protection and continuity of service.

Question 18

Series-rated equipment is also referred to as ____.

Accepted Answer

Series-rated equipment is referred to as series-connected because it involves connecting circuit breakers in series with one another to provide protection against short circuits.

Question 19

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

Accepted Answer

The answer of Fused switches are available in ratings of...

Question 20

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

Conventional plug fuses have a base referred to as an Edison base, which is of the same shape as the base on a light bulb. This design allows for easy installation and compatibility with standard electrical sockets.

Quiz 17: Overcurrent Protection: Fuses and Circuit Breakers

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

What are some prohibitions on the location of overcurrent devices?

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.

____ circuit breakers are the most common type in use today.

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

What are some factors that influence speed of response of an overcurrent device?

An interrupting rating is a(n) ____ rating, and measures 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.

____ is the ability of the equipment (the entire assembly) to withstand a fault current equal to or less than the rating for the length of time it takes the specified overcurrent device to open the circuit to the equipment.

How do thermal-magnetic circuit breakers work?

What is the purpose of peak let-through charts?

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.

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

In the case of a delta, 3-phase, corner-grounded "B" phase system, a device called a ____ can be installed in the "B" phase.

Class ____ fuses formerly were called NEC or Code fuses.

Name and describe the class of fuses used for control circuit protection.

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

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

Series-rated equipment is also referred to as ____.

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

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.

Quiz 17: Overcurrent Protection: Fuses and Circuit Breakers

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

What are some prohibitions on the location of overcurrent devices?

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.

____ circuit breakers are the most common type in use today.

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

​What are some factors that influence speed of response of an overcurrent device?

An interrupting rating is a(n) ____ rating, and measures 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.

____ is the ability of the equipment (the entire assembly) to withstand a fault current equal to or less than the rating for the length of time it takes the specified overcurrent device to open the circuit to the equipment.

How do thermal-magnetic circuit breakers work?

What is the purpose of peak let-through charts?

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.

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

In the case of a delta, 3-phase, corner-grounded "B" phase system, a device called a ____ can be installed in the "B" phase.

Class ____ fuses formerly were called NEC or Code fuses.

Name and describe the class of fuses used for control circuit protection.

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

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

Series-rated equipment is also referred to as ____.

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

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.

What are some factors that influence speed of response of an overcurrent device?