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Arcing is a luminous discharge of electricity across an insulating medium. Electric arcs operate at temperatures between

5,000 and 15,000 F

If the difference between the current leaving and returning through the current transformer of the GFCI protection device exceeds ______, the solid state circuitry de-energizes the circuit

5mA

To help reduce the hazard of t electrical fires from a parallel fault, the NEC requires a listed AFCI protection device to protect _______ wiring in dwelling unit bedrooms

Branch circuit

When equipment does not have a withstand rating sufficient for the available fault current, the equipment can be protected by the use of _________

Current listing fuses

A GFCI protection device contains an internal monitor that prevents the device from being turned on if there is a neutral to case connection downstream of the device.

False

Ground fault protection devices protect equipment from Samsung ground fault currents by opening all ungrounded conductors of the faulted circuit. This device also protects People

False

Inverse time breakers operate on the principle that as the current decreases, the time it takes for the device to open decrease

False

A ground fault type parallel arc only occurs when a ground a path is present. This type of acting fault can be quickly cleared by a

GFCI & AFCI

To remove dangerous touch voltage on metal parts from a ________, the fault-current path must have low impedance to allow the fault current to quickly rise to facilitate the opening of the protection device

Ground fault

________ breakers operate on the principle of electromagnetism only and are used for very large motors

Instantaneous trip

__________ breakers operate on the principle that as the current increases, the time it takes for the device to open decreases

Inverse time

A fuse consists of an element electrically connected to end blades, which is enclosed in a tube and surrounded by a _______ filler material

Nonconductive

An _____ is the operation of equipment or conductors in excess of Their rated ampacity

Overload

As current flows through the element of a fuse, it generates heat. When sustained overload occurs, the heat melts _______, stopping the flow

Portion of the element

When a short circuit or forums fault occurs, _______ melt removing the load from the source very quickly

Several elements

Equipment must have a ________ current rating that permits the protection device to clear a short circuit or ground fault without extensive damage to the components of the circuit

Short circuit

The current in a short circuit type arc is limited by the system impedance and the impedance of the arcing fair. Typical fault current will be above 75A but no above

450A

Magnetic time-delay circuit breakers operate on the on the solenoid principle where a movable core, held with a spring is moved by the magnetic field a ________

B or C

Severe electric shock or death can occur if a person touches the undergrounded and the neutral conductors at the same time, even if the circuit is GFCI protected

True

The opening time for a protection device is inversely proportional to the magnitude of the current. The greater the current value, the less time it takes for the protection device to open

True

Typically when a GFCI protection device fails the switching contacts Ramon closed and the device will continue to provide power without GFCI protection

True

Unless marked otherwise, circuit breakers have a 5,000 AIC rating and fuses have a 10,000 AIC rating

True

Unsafe arcing faults can occur in one of two ways, as series acting faults or as parallel acting faults. The most dangerous is the parallel arcing fault

True

A GFCI is designed to protect persons against electric shock. It operates on the principle of monitoring the imbalance of the circuits _______ conductors

Ungrounded and grounded

The available short circuit is different at each point of the electrical system; it is the highest at the __________

Utility transformer

According to NEMA report, 11% of the GFCI breakers protecting indoor receptacles failed, and ________ percent protecting outdoor receptacles failed

20

A short circuit is a ________ electrical connection between any two conductors of the electrical system

A or B

_________breakers permit the thermal trip setting to be adjusted to coordinate the circuit breaker's operation with other protection devices

Adjustable trip

Factors that impact the available short circuit current include circuit conductor ___________

All of these

Factors that impact the available short-circuit current include transformer ____________

All of these

The purpose of overcurrent protection is to protect conductors and equipment against excessive or dangerous temperatures because of over current. Overcurrent is is current in excess of the rated current of equipment or conductors. May result in _______

All of these

To protect against electric shock or to prevent a fire, a dangerous ________ must quickly be removed by opening the circuits overcurrent device

All of these

A thermal magnetic circuit breaker typically clears fault current in less that 3 to 5 cycles when subjected to a

B or C

The ________ sensing element causes the circuit breaker to open when a predetermined calibration temperature is reached

Thermal

A series arc can occur when the conductor in series with the load is unintentionally broken. A series arc fault current is load limited

True

An AFCI protection device provides protection from an arcing fault by recognizing the characteristics unique to a parallel arcing fault and by functioning to de energize the circuit when an arc fault is detected

True

Available short circuit current is current in amperes that is available at a given point in the electrical system

True

Circuit breakers and fuses are intended to interrupt the circuit and they must have an ampere interrupting eating sufficient for the available short circuit current

True

If the protection device is not rated to interrupt the available fault current at its listed voltage rating, it can explode while attempting to clear the fault

True


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