IEC First Year Exam Questions and Answers With Verified Solutions 2025
What is the result if the neutral wire becomes open on a multiwire circuit having unequal loads? -
✔✔The 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 ___. - ✔✔240.15(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. - ✔✔150
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? -
✔✔Because 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) ___. - ✔✔is 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 ___. - ✔✔24 in.
An extension ladder should extend ___ feet above the top of the building and be secured. - ✔✔3ft.
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. -
✔✔$9.00
, ___ can be described as the point of demarcation between where the serving utility ends and the
premises wiring begins. - ✔✔Service Point
If a 60-watt lamp operates for 21 hours, the utility will bill for ___ kWh. - ✔✔1.260
To minimize conductor insulation damage and arcing damage to electrical equipment during a ground
fault or a short circuit, ___ should be minimized. - ✔✔a. time duration of the fault
Article ___ in the NEC ® covers grounding and bonding of electrical systems. - ✔✔250
Self-tapping sheet metal screws (TEK screws) ___ permitted to be used to connect the equipment
grounding conductor to a metal box. - ✔✔are not
For a 100-Amp, 120/240-V, 3W commercial service, ___ AWG copper THHN/THWN conductors are the
smallest permitted for the ungrounded conductors. - ✔✔3
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. - ✔✔larger
Which of the following is a 3/0 AWG conductor? - ✔✔000
When calculating the size of the required service, you should consult household electric clothes dryer
demand factors given in Table ___. - ✔✔220.54
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. - ✔✔50
Without exceptions, all metal parts of an indoor spa or hot tub must be bonded. - ✔✔true
Article ___ of the NEC ® is the article that gives requirements for swimming pool installations. - ✔✔680
What is the result if the neutral wire becomes open on a multiwire circuit having unequal loads? -
✔✔The 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 ___. - ✔✔240.15(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. - ✔✔150
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? -
✔✔Because 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) ___. - ✔✔is 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 ___. - ✔✔24 in.
An extension ladder should extend ___ feet above the top of the building and be secured. - ✔✔3ft.
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. -
✔✔$9.00
, ___ can be described as the point of demarcation between where the serving utility ends and the
premises wiring begins. - ✔✔Service Point
If a 60-watt lamp operates for 21 hours, the utility will bill for ___ kWh. - ✔✔1.260
To minimize conductor insulation damage and arcing damage to electrical equipment during a ground
fault or a short circuit, ___ should be minimized. - ✔✔a. time duration of the fault
Article ___ in the NEC ® covers grounding and bonding of electrical systems. - ✔✔250
Self-tapping sheet metal screws (TEK screws) ___ permitted to be used to connect the equipment
grounding conductor to a metal box. - ✔✔are not
For a 100-Amp, 120/240-V, 3W commercial service, ___ AWG copper THHN/THWN conductors are the
smallest permitted for the ungrounded conductors. - ✔✔3
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. - ✔✔larger
Which of the following is a 3/0 AWG conductor? - ✔✔000
When calculating the size of the required service, you should consult household electric clothes dryer
demand factors given in Table ___. - ✔✔220.54
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. - ✔✔50
Without exceptions, all metal parts of an indoor spa or hot tub must be bonded. - ✔✔true
Article ___ of the NEC ® is the article that gives requirements for swimming pool installations. - ✔✔680
