IEC Final Exam Year 1
1. What is the result if the neutral wire becomes open on a multiwire
circuit having unequal loads?
a.
The load of higher resistance would overheat and probably be damaged.
b.
The load of lesser resistance would overheat and probably be damaged.
c.
No effect until one load is turned off or opens.
d.
No effect.: a.
The load of higher resistance would overheat and probably be damaged.
2. Circuits 7 and 9 share a neutral. This is a multiwire branch circuit. If Ckt. 7
is drawing 13 amps and Ckt. 9 is drawing 16 amps, how much current is
flowing in the neutral?
a.3
b.13
c.29
d.16: 3 Amps
3. The Code reference that specifies the type of disconnecting means (circuit
breaker for example) that can be used on a multiwire branch circuit that feeds
devices mounted on the same yoke [a stack switch or a duplex receptacle for
example] is ___.Note: Select N/A (not applicable) if there is not an NEC®
requirement.
a.Article 100
b.240.15(B)(1)
c.404.8(A)
d.N/A: b. 240.15(B)(1)
4. Voltmeters are connected in ___ with the load when used to measure
voltage across a load in a circuit.: Parallel
,IEC Final Exam Year 1
5. The neutral has been removed from the neutral bar in the circuit shown in
Figure 128.407. Lamp 3 is connected in ___ with Lamps 1 and 2.: Series
(3 wire parallel circuits turn to series when the neutral is disconnected from the
neutral bar)
6. What is the minimum number of receptacles required in an unfinished
basement?
a.2
b.4
c.1
d.0: c. 1
7. The overall diameter (including insulation) of a 250 kcmil THHN/THWN
copper conductor is ___ inches?
a..082
b..397
c..765
d..711
e..575: d. 711
NEC Chapter 9 Table 5 pg 701
8. What part of the NEC® is a reference for calculating conduit fill where
all conductors are the same size?
a.Article 100
b.Table 310.15(B)(16)
c.Annex C
d.Table 314.16(A): c. Annex C
9. What is the minimum trade size Schedule 80 PVC required to contain
four 8 AWG THHN/THWN copper conductors?
a.1
, IEC Final Exam Year 1
b.3/4
c.11/4
d.11/2
e.none of these: b. 3/4
NEC Annex C
10. Eleven #12, five #10, and six #6 THHN/THWN conductors will be
installed in a run of EMT. The smallest trade size EMT you can use is ___.
a.11/2
b.21/2
c.11/4
d.2
e.1: c. 11/4
NEC Chapter 9 Tables 4 and 5
11. A short length of EMT is run between two panels. The ampacity values
for the conductors in this EMT need not be derated, as long as the length of
the EMT does not exceed ___.
a.12 inches
b.18 inches
c.24 inches: c. 24 inches
12. An extension ladder should extend ___ feet above the top of the building
and be secured.
a.four
b.three
c.two
d.one: b. three
13. ___ can be described as the point of demarcation between where the
serving utility ends and the premises wiring begins.
1. What is the result if the neutral wire becomes open on a multiwire
circuit having unequal loads?
a.
The load of higher resistance would overheat and probably be damaged.
b.
The load of lesser resistance would overheat and probably be damaged.
c.
No effect until one load is turned off or opens.
d.
No effect.: a.
The load of higher resistance would overheat and probably be damaged.
2. Circuits 7 and 9 share a neutral. This is a multiwire branch circuit. If Ckt. 7
is drawing 13 amps and Ckt. 9 is drawing 16 amps, how much current is
flowing in the neutral?
a.3
b.13
c.29
d.16: 3 Amps
3. The Code reference that specifies the type of disconnecting means (circuit
breaker for example) that can be used on a multiwire branch circuit that feeds
devices mounted on the same yoke [a stack switch or a duplex receptacle for
example] is ___.Note: Select N/A (not applicable) if there is not an NEC®
requirement.
a.Article 100
b.240.15(B)(1)
c.404.8(A)
d.N/A: b. 240.15(B)(1)
4. Voltmeters are connected in ___ with the load when used to measure
voltage across a load in a circuit.: Parallel
,IEC Final Exam Year 1
5. The neutral has been removed from the neutral bar in the circuit shown in
Figure 128.407. Lamp 3 is connected in ___ with Lamps 1 and 2.: Series
(3 wire parallel circuits turn to series when the neutral is disconnected from the
neutral bar)
6. What is the minimum number of receptacles required in an unfinished
basement?
a.2
b.4
c.1
d.0: c. 1
7. The overall diameter (including insulation) of a 250 kcmil THHN/THWN
copper conductor is ___ inches?
a..082
b..397
c..765
d..711
e..575: d. 711
NEC Chapter 9 Table 5 pg 701
8. What part of the NEC® is a reference for calculating conduit fill where
all conductors are the same size?
a.Article 100
b.Table 310.15(B)(16)
c.Annex C
d.Table 314.16(A): c. Annex C
9. What is the minimum trade size Schedule 80 PVC required to contain
four 8 AWG THHN/THWN copper conductors?
a.1
, IEC Final Exam Year 1
b.3/4
c.11/4
d.11/2
e.none of these: b. 3/4
NEC Annex C
10. Eleven #12, five #10, and six #6 THHN/THWN conductors will be
installed in a run of EMT. The smallest trade size EMT you can use is ___.
a.11/2
b.21/2
c.11/4
d.2
e.1: c. 11/4
NEC Chapter 9 Tables 4 and 5
11. A short length of EMT is run between two panels. The ampacity values
for the conductors in this EMT need not be derated, as long as the length of
the EMT does not exceed ___.
a.12 inches
b.18 inches
c.24 inches: c. 24 inches
12. An extension ladder should extend ___ feet above the top of the building
and be secured.
a.four
b.three
c.two
d.one: b. three
13. ___ can be described as the point of demarcation between where the
serving utility ends and the premises wiring begins.
