Ricardos 3rd year second test ( NFPA 70E ) ch.1-9 Questions with 100% Correct Answers A(n) ___is best defined as any current in excess of the rated current of equipment or the ampacity of a conductor. It may result from overload or short circuit
- branch-circuit overcurrent device
- overcurrent
- overload
- supplementary overcurrent device - Correct Answer B. overcurrent
NEC Reference: 100
A(n) ____ is a current greater than the equipment rated current or conductor ampacity, which is confined to the normal conductive paths provided by the conductors and other equipment.
- branch-circuit overcurrent device
- overcurrent
- overload
- supplementary overcurrent device - Correct Answer C. overload
- Overload
- Short circuit
- Too many loads connected to a circuit
- Ungrounded circuit - Correct Answer B. short circuit
- current limiter
- ground conductor
- ground fault
- overload - Correct Answer C. ground fault 1 / 4
What electrical circuit condition best describes a phase or ungrounded conductor that comes into contact with another phase conductor or grounded conductor object?
A type of short circuit defined as an unintentional connection between an ungrounded conductor and ground, an equipment grounding conductor, or grounded equipment is a(n) _____
An overcurrent that has current flow outside the normal conduction path could be a(n) _____?
- ground fault
- overload
- short circuit
- both A and C
- A, B, and C - Correct Answer D. both A and C
- ground fault
- overload
- short current
- B and C
- A, B, and C - Correct Answer B.overload
- ground fault
- normal operation
- overload
- short circuit - Correct Answer B. normal operation
- ground fault
- normal operation
- overload
- short circuit - Correct Answer C. overload 2 / 4
An overcurrent that stays in the normal conduction path could be a(n) _____
The following 120-volt loads are connected to a 120-volt circuit using 12 AWG THWN-2 copper conductors and protected by a 20-ampere overcurrent device: L1 = 20 Ω, L2 = 12 Ω. The circuit condition is a(n) _____
The following 240-volt loads are connected to a 240-volt single-phase circuit using 4 AWG THW copper conductors and protected by an 80-ampere overcurrent device: L1 = 150 ohms, L2 = 200 ohms, L3 = 5 ohms, L4 = 3 ohms. The circuit condition is a(n) ______.
A 240-volt single-phase circuit using 4 AWG THW copper conductors and protected by an 80-ampere overcurrent device has an event where the circuit and load impedance results in a total resistance of 0.0024 ohms. Select the type of circuit condition occurring.
- ground fault
- normal operation
- overload
- short circuit - Correct Answer D. short circuit
- the point of time that fault occurs on the cycle
- The power factor of the faulted current
- The voltage of the system
- both A and B
- all of the above - Correct Answer D. both A and B
T/F An arcing fault current is always less than the available bolted fault current value at a specific location. - Correct Answer True The degree or magnitude of asymmetry of fault current depends upon ____?
The percentage of current flow shown in the figure is approximately _____as compared to a 3-phase bolted fault current.
A. 87%
B. 89%
C. 99%
- 25% to 125% - Correct Answer A. 87%
In a 480/277-volt 3-phase wye system, the arcing fault current range using older guidelines is approximately ____of the 3-phase bolted fault current.
A. 87% 3 / 4
- 89% to 38%
- 125% to 25%
- none of the above - Correct Answer B. 89% to 38%
- Working energized with heavy clothing and gloves
- Working on circuits which are listed to prevent bolted line-to-line faults
- Working on deenergized equipment under employer lockout/tagout procedure
- Working under the direction of an authorized employee - Correct Answer C Working on deenergized
- Energizing transformers
- Starting a motor
- Starting heating elements
- Resistive heater
- a. and b - Correct Answer E. A and B
- asymmetrical
- Different
- irregular
- symmetrical - Correct Answer D. symmetrical
- / 4
Arcing faults create a very dangerous condition for Electrical Workers in close proximity to an arcing fault because of the tremendous amount of thermal energy emitted at the point of the fault. Which of the following is a recognized safe work practice to prevent serious worker injury or death?
equipment under employer lockout/tagout procedure Harmless overloads routinely are created by temporary inrush or surge current from which of the following?
When analyzing a short-circuit current, if the fault current level is equal above and below the zero axis of a sine wave, the fault current is ___
T/F An inverse time-current characteristic is defined as the higher the overcurrent level, the faster the reaction time or interrupting time of the overcurrent device. - Correct Answer True