Exam 17: Overcurrent Protection: Fuses and Circuit Breakers

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.

Series-rated equipment is also referred to as ____.

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

____ 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.

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

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

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

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.

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

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

What is the purpose of peak let-through charts?

Class ____ fuses formerly were called NEC or Code fuses.

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

What are some prohibitions on the location of overcurrent devices?

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

How do thermal-magnetic circuit breakers work?

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

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.

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.

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