Question 31
What is the main function of an overcurrent protective device such as a circuit breaker?
Question 32
When using a portable extension cord for a power tool outdoors, which practice is safest?
Question 33
When terminating a metal-clad (armoured) cable into a metal box, what additional component is often required to ensure bonding continuity?
Question 34
A feeder supplies a 347/600 V, 3-phase, 4-wire lighting and power system. After a fault, several luminaires are failing. Measurements show 347 V phase-to-neutral and 600 V phase-to-phase, but neutral-to-ground voltage is fluctuating significantly. What is the most likely issue?
Question 35
Which device is designed to quickly disconnect a circuit when it detects a ground fault that could cause shock?
Question 36
A facility experiences nuisance tripping of 30 mA ground fault protection on a feeder that supplies several variable frequency drives (VFDs). What mitigation measure is most appropriate?
Question 37
Which device is used to protect people from electric shock due to ground faults in locations such as bathrooms or outdoor receptacles?
Question 38
Which statement best describes a ground fault?
Question 39
Which device is primarily intended to protect people from electric shock due to ground faults?
Question 40
An equipment grounding conductor is required to be connected to metal boxes. What is the primary reason for this?
Question 41
During an inspection of a large metal service raceway, you find that bonding jumpers are missing around expansion fittings. What risk does this create?
Question 42
A large variable frequency drive (VFD) is causing nuisance tripping of upstream ground-fault protective devices. What is the most appropriate approach?
Question 43
What is the primary purpose of a ground-fault circuit interrupter (GFCI) receptacle in a dwelling unit bathroom?
Question 44
What is the main function of an equipment grounding conductor in an electrical system?
Question 45
What is the safest way to handle a portable cord that has damaged outer insulation exposing the inner conductors?
Question 46
A main bonding jumper is incorrectly installed between neutral and ground in a downstream panelboard that is fed by a four-wire feeder from the service. What is the primary concern?
Question 47
What is the primary purpose of a ground-fault circuit interrupter (GFCI) device?
Question 48
A length of nonmetallic-sheathed cable labeled '14/3 with ground' contains which of the following conductors?
Question 49
What should you do if you find an extension cord at a job site with damaged insulation exposing copper conductors?
Question 50
During a service upgrade, an electrician installs a main bonding jumper in the service disconnect enclosure. What is its purpose?
Question 51
A facility with sensitive electronic equipment is experiencing nuisance tripping of ground-fault protection on the main service due to normal neutral-to-ground leakage currents. What is a common design strategy to address this while maintaining protection?
Question 52
What is the main purpose of a ground-fault circuit interrupter (GFCI) receptacle?
Question 53
At a service disconnect, the main bonding jumper is omitted and the neutral bar is isolated from the equipment grounding bar. All branch circuits have equipment grounding conductors, and the grounding electrode conductor is connected only to the equipment grounding bar. What is the primary safety concern?
Question 54
What is the primary purpose of an equipment grounding conductor?
Question 55
What is the main purpose of bonding metal boxes and raceways to the equipment grounding conductor?
Question 56
What is the safest practice when resetting a circuit breaker that has tripped?
Question 57
Why is voltage drop a concern on long branch-circuit runs?
Question 58
What is the main purpose of a ground-fault circuit interrupter (GFCI) device?
Question 59
What is the primary purpose of bonding metal raceways and enclosures?
Question 60
What is the primary purpose of a GFCI device on a 120 V receptacle circuit?