IEC FIRST YEAR EXAM
STUDYQUESTIONS &
SOLUTIONS(RATED A+)
What is the result if the neutral wire becomes open on a multiwire circuit having unequal
loads? - ANSWERThe load of higher resistance would overheat and probably be
damaged.
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 ___. -
ANSWER240.15(B)(1)
Refer to the panel schedule shown in Figure 128.231. If the neutral is removed from the
neutral bar, ___ volts will be applied to the TV. - ANSWER150
A 12/3 cable is installed from a 120/240-V, 1Ø panel and feeds a split-wired duplex
receptacle. One "hot" is connected to a 20A breaker in panel space 1. The second "hot"
is connected to a 20A breaker in space 3. A 16-amp load is connected to the upper
receptacle and a 14-amp load is connected to the lower receptacle. Which of the
following will happen if the neutral is removed from the receptacle? - ANSWERBecause
a higher voltage will be applied, 120-volt equipment could be destroyed.
Refer to Figure 129.106. With the equipment energized and the power used by the
element connected at T3 & T4 is 0.3kW, the power used by the equipment (all 4
elements) ___. - ANSWERis 1.2 kW
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 ___. - ANSWER24 in.
An extension ladder should extend ___ feet above the top of the building and be
secured. - ANSWER3ft.
What is the monthly energy cost to operate a 250-watt high-pressure sodium lamp?
Electricity costs $0.15 per kW-hr and the lamp will be ON for 8 hours per day. There are
30 days in a billing month. - ANSWER$9.00
___ can be described as the point of demarcation between where the serving utility
ends and the premises wiring begins. - ANSWERService Point
If a 60-watt lamp operates for 21 hours, the utility will bill for ___ kWh. - ANSWER1.260
, To minimize conductor insulation damage and arcing damage to electrical equipment
during a ground fault or a short circuit, ___ should be minimized. - ANSWERa. time
duration of the fault
Article ___ in the NEC ® covers grounding and bonding of electrical systems. -
ANSWER250
Self-tapping sheet metal screws (TEK screws) ___ permitted to be used to connect the
equipment grounding conductor to a metal box. - ANSWERare not
For a 100-Amp, 120/240-V, 3W commercial service, ___ AWG copper THHN/THWN
conductors are the smallest permitted for the ungrounded conductors. - ANSWER3
Loads, such as heating and air conditioning, that do not operate at the same time are
said to be noncoincident loads. While separate circuits must be designed to serve each
load, when calculating service load only the ___ of two noncoincident loads needs to be
included. - ANSWERlarger
Which of the following is a 3/0 AWG conductor? - ANSWER000
When calculating the size of the required service, you should consult household electric
clothes dryer demand factors given in Table ___. - ANSWER220.54
The Standard for Electrical Safety in the Workplace requires that all electrical equipment
operating at over ___ volts to ground be de-energized and locked out before anyone is
permitted to work on or near the equipment. - ANSWER50
Without exceptions, all metal parts of an indoor spa or hot tub must be bonded. -
ANSWERtrue
Article ___ of the NEC ® is the article that gives requirements for swimming pool
installations. - ANSWER680
What is the minimum number of 125-volt, 15- or 20-ampere convenience receptacles
that the NEC ® requires to be installed near a permanently installed pool? The pool is
located in your neighbor's backyard. - ANSWERone
While installing Cat 5 cable, pulling too hard can damage the ___. - ANSWERjacket,
conductor, insulation
When a portable generator provides power for frame-mounted receptacles only, the
NEC ® ___ require the frame to be connected to a grounding electrode. -
ANSWERdoes not
Transfer switches use a ___ to prevent the feedback of electricity between the
generator power and the normal utility power. - ANSWERmechanical interlock
STUDYQUESTIONS &
SOLUTIONS(RATED A+)
What is the result if the neutral wire becomes open on a multiwire circuit having unequal
loads? - ANSWERThe load of higher resistance would overheat and probably be
damaged.
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 ___. -
ANSWER240.15(B)(1)
Refer to the panel schedule shown in Figure 128.231. If the neutral is removed from the
neutral bar, ___ volts will be applied to the TV. - ANSWER150
A 12/3 cable is installed from a 120/240-V, 1Ø panel and feeds a split-wired duplex
receptacle. One "hot" is connected to a 20A breaker in panel space 1. The second "hot"
is connected to a 20A breaker in space 3. A 16-amp load is connected to the upper
receptacle and a 14-amp load is connected to the lower receptacle. Which of the
following will happen if the neutral is removed from the receptacle? - ANSWERBecause
a higher voltage will be applied, 120-volt equipment could be destroyed.
Refer to Figure 129.106. With the equipment energized and the power used by the
element connected at T3 & T4 is 0.3kW, the power used by the equipment (all 4
elements) ___. - ANSWERis 1.2 kW
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 ___. - ANSWER24 in.
An extension ladder should extend ___ feet above the top of the building and be
secured. - ANSWER3ft.
What is the monthly energy cost to operate a 250-watt high-pressure sodium lamp?
Electricity costs $0.15 per kW-hr and the lamp will be ON for 8 hours per day. There are
30 days in a billing month. - ANSWER$9.00
___ can be described as the point of demarcation between where the serving utility
ends and the premises wiring begins. - ANSWERService Point
If a 60-watt lamp operates for 21 hours, the utility will bill for ___ kWh. - ANSWER1.260
, To minimize conductor insulation damage and arcing damage to electrical equipment
during a ground fault or a short circuit, ___ should be minimized. - ANSWERa. time
duration of the fault
Article ___ in the NEC ® covers grounding and bonding of electrical systems. -
ANSWER250
Self-tapping sheet metal screws (TEK screws) ___ permitted to be used to connect the
equipment grounding conductor to a metal box. - ANSWERare not
For a 100-Amp, 120/240-V, 3W commercial service, ___ AWG copper THHN/THWN
conductors are the smallest permitted for the ungrounded conductors. - ANSWER3
Loads, such as heating and air conditioning, that do not operate at the same time are
said to be noncoincident loads. While separate circuits must be designed to serve each
load, when calculating service load only the ___ of two noncoincident loads needs to be
included. - ANSWERlarger
Which of the following is a 3/0 AWG conductor? - ANSWER000
When calculating the size of the required service, you should consult household electric
clothes dryer demand factors given in Table ___. - ANSWER220.54
The Standard for Electrical Safety in the Workplace requires that all electrical equipment
operating at over ___ volts to ground be de-energized and locked out before anyone is
permitted to work on or near the equipment. - ANSWER50
Without exceptions, all metal parts of an indoor spa or hot tub must be bonded. -
ANSWERtrue
Article ___ of the NEC ® is the article that gives requirements for swimming pool
installations. - ANSWER680
What is the minimum number of 125-volt, 15- or 20-ampere convenience receptacles
that the NEC ® requires to be installed near a permanently installed pool? The pool is
located in your neighbor's backyard. - ANSWERone
While installing Cat 5 cable, pulling too hard can damage the ___. - ANSWERjacket,
conductor, insulation
When a portable generator provides power for frame-mounted receptacles only, the
NEC ® ___ require the frame to be connected to a grounding electrode. -
ANSWERdoes not
Transfer switches use a ___ to prevent the feedback of electricity between the
generator power and the normal utility power. - ANSWERmechanical interlock
