Electrical Level 2 Module 10
In residential applications, the available fault current is seldom higher then
10,000 amps
What is normally the highest short circuit current in residential applications?
10,000A
Every circuit breaker must have its interrupting rating shown on the circuit breaker, unless it is rated for
5,000A
What is the highest voltage rating for circuit breakers used on DC systems that UL recognizes?
600V
Which of the following best describes a dual element fuse?
A fuse having an overcurrent limit and a time delay before activation
Each group of circuit breakers are classified by the largest
Ampere rating
What color is printed on the labels of standard interrupting capacity circuit breakers?
Black
The organizations that test and list circuit breakers are
CSA and UL
Which of the following is defined by UL as a device that trips when a fault current to ground is 6mA or more?
Class A
At current below threshold of about 1000 A, the current limiting circuit breaker performs in a manner similar to
Conventional thermomagnetic circuit breakers
The name given to the time-current relationship among a number of overcurrent devices connected in series, such as fuses in a main feeder, subfeeder, and branch circuits.
Coordination
NEC section 240
Covers overcurrent protection
Circuit breakers are classified according to the given
Current range
This type of circuit breaker has an interrupting rating of 65,000 A symmetrical at 240 VAC
FH-type circuit breaker
What are the two types of GFCI receptacles?
Feed-through and Non feed-through
Which of the following best describes where the NEC allows the use of Edison base fuses?
For replacements in existing installations
These are types of automatic overload devices that are normally used in electrical circuits to prevent fires and the destruction of the circuit in its associated equipment.
Fuses and circuit breakers
When a common molded case circuit breaker trips, in what position will the operating handle be?
Halfway between the On and Off postion
Where is the ampere rating normally marked on circuit breakers?
On the handle
Where is the amp rating of a circuit breaker located?
On the handle of the device
These type of drawings do not have to be detailed
Single Line Schematic drawings
______________ have a very high speed of response to overcurrents.
Single element fuses
Which of the following is the most important consideration when working with overcurrent protection devices?
The correct interrupting capacity
On renewable cartridge fuses, which part of the fuse is normally renewed?
The link
What must be used in conjunction with Type S plug fuses when they are installed in a fuse holder?
Type S adapter
Cartridges fuses used for branch circuit protection must be marked with the
ampere rating, voltage rating and the Interrupting rating.
The interrupting rating of a circuit breaker is as important in application as the voltage and current ratings and should be considered
each time a Breaker is applied