IEC YEAR 3 FINAL EXAM NEWEST
ACTUAL EXAM, PRACTICE TEST AND
STUDY GUIDE QUESTIONBANK WITH
CORRECT DETAILED ANSWERS
(VERIFIED ANSWERS) | ALREADY
GRADED A+ 2024-2025
The primary purpose of bonding metal equipment enclosures, metal raceways, and the
grounded power supply together is to ___.I. cause the quick operation of OCPDsII. keep
all metal parts at the same voltageIII. limit voltage surges
Select one:
a.I, II & III
b.I & III only
c.II & III only
d.I only
e.I & II only Correct Answer d. I only
A ground rod is the only grounding electrode at a service. If the GEC becomes loose
when connected to the rod, the branch-circuit breakers in the service panel will take ___
amount of time to open if a ground fault occurs in one of the branch circuits.
Select one:
a.a longer
b.a shorter
c.the same Correct Answer c. the same
All of the following are considered a short circuit, except for ___.
Select one:
a.line-to-line fault
b.phase-to-phase fault
c.neutral-to-ground fault
d.phase-to-neutral fault Correct Answer d. phase-to-neutral fault
You should observe "no smoking" areas near any flammable materials.
Select one:
a.True
,b.False Correct Answer a. true
Never carry heavy objects when climbing a ladder.
Select one:
a.True
b.False Correct Answer a. true
If your power tool has auxiliary handles, they must be used to keep the tool in your grip.
Select one:
a.True
b.False Correct Answer a. true
You should be aware of hazards created by other trades working near you.
Select one:
a.True
b.False Correct Answer a. true
Always place your ladder on flat, stable surfaces and ___.
Select one:
a.anchor it to the floor
b.observe the 3-point rule
c.have a co-worker hold it
d.all of these Correct Answer b. observe the 3-point rule
Lock-out and verify before working on or near any electrical equipment.
Select one:
a.True
b.False Correct Answer a. true
Be sure the GFCI receptacles are in good working order and tested ___.
Select one:
a.annually
b.weekly
c.regularly
d.daily Correct Answer c. regularly
Which of the following voltage systems is solidly grounded?I. 120/208-volt, 3Ø, 4-wireII.
120/240-volt, 3Ø, 4-wireIII. 277/480-volt, 3Ø, 4-wire
Select one:
,a.I, II & III
b.I & II only
c.II only
d.I & III only
e.I only Correct Answer a. I, II & III
A single-phase transformer is supplied from a 480-volt circuit and delivers power to a
120-volt load. The secondary conductors are fused. If one of the secondary conductors
is connected to a grounding electrode, the secondary fuses will open.
Select one:
a.True
b.False Correct Answer b. false
A three-phase, four-wire, wye-connected system is normally ___ grounded.
Select one:
a.delta
b.not
c.center (at the point where the common leads of each transformer are connected
together)
d.corner Correct Answer c. center (at the point where the common leads of each
transformer are connected together)
When a 3Ø, 3-W supply system delivers 240 volts, the system has a neutral.
Select one:
a.True
b.False Correct Answer b. false
When a 3Ø, 3-W supply system delivers 240 volts, the system is ___ connected.
Select one:
a.wye
b.delta Correct Answer b. delta
When a 3Ø, 3-W supply system delivers 480 volts, the system has a neutral.
Select one:
a.True
b.False Correct Answer b. false
When a 3Ø, 4-W supply system delivers 277/480 volts, the system is ___ connected.
Select one:
a.wye
, b.delta Correct Answer a. wye
When a 3Ø, 4-W supply system delivers 120/208 volts, the system has a neutral.
Select one:
a.True
b.False Correct Answer a. true
In a 277/480-volt, 3-phase, 4-wire system, the maximum voltage to ground is ___.
Select one:
a.208 volts
b.240 volts
c.277 volts
d.120 volts Correct Answer c. 277 volts
Three 120-volt circuits will be installed to serve receptacles that are required to be GFCI
protected. The three circuits will be installed in one conduit to a J-box, and then MC
cable will be run from there to the receptacles. Three GFCI circuit breakers will be
installed in a 120/208-volt, 3-phase, 4-wire panelboard. The fewest number of neutrals
that can be installed in the conduit is ___.
Select one:
a.two
b.three
c.one Correct Answer b. three
In a 480-volt, corner-grounded delta system, the maximum voltage to ground is ___.
Select one:
a.208 volts
b.480 volts
c.277 volts
d.240 volts Correct Answer b. 480 volts
When a 3Ø, 4-W supply system delivers 277/480 volts, the system has a neutral.
Select one:
a.True
b.False Correct Answer a. true
NEC® Sections 250.20, 250.21, and 250.22 state when a system is required, permitted,
or not permitted to be grounded. Which of these transformer secondaries is required to
be grounded?I. 120 to 12 volt AC transformer installed outside overhead to tree-
mounted, low-voltage lightingII. 480 to 120/240 VAC, 1Ø, 3-wire to a panelboardIII. 480
to 120 VAC for a motor control circuit
