IEC 2nd semester midterm review
A water filtration system is to be connected to a receptacle that is located outdoors. The receptacle cover shown at ___ should be installed.
a. (bubble cover) 2020 NEC: 406.9(B)(2)(a) b. (two seperate flaps) c.either a or b d.neither a nor b
What is the minimum burial depth of a 20-Amp, GFCI-protected, 120-volt branch circuit under a two family dwelling (duplex)? The wiring method is Type UF cable. The duplex is built on a concrete slab.
a.0" b.24" c.18" d.12" e.none of these The correct answer is 6 inches for direct burial cable - a concrete slab will be at least 4 inches thick.
What is the minimum burial depth of a 20-Amp, GFCI-protected, 120-volt branch circuit under a two family dwelling (duplex)? The wiring method is Type UF cable. The duplex is NOT built on a concrete slab.
a.0" b.24" c.18" d.12" 2020 NEC: 300.5 (Table) e.none of these
Which Article in the NEC® covers electrical disconnects for dishwashers?
a.110 b.210 c.300 d.422 d
An 18 watt chime system that draws 1.5 amps is to be installed in a commercial building. For this circuit, 330 feet of 18 AWG solid copper cable is used. The voltage at the transformer secondary is 13.2 volts. What minimum size wire would be required to supply no less than 11.5 volts to the chime? Use K = 12.3.
a.12 b.18 c.14 d.10 e.16 d
120/240 v 3-ph, 4-w. washing machine- 7.2 amps @220 v shirt press- 1800w @230 volts clothes dryer-5000 watts @250 v Figure 119.570 shows an equipment layout in a laundromat. The resistance of the clothes dryer (Rcd) is ___ ohms.
a.12.5 Rcd = [Erated]2÷ Prated = (250)2 ÷ 5000 = 12.5 ohms b.20 c.20.8333 d.11.52 e.12.0
A window (room) air conditioner is cord-connected and the receptacle will be connected to a branch circuit that supplies other receptacles. The air conditioner will draw 9.7 amps. The smallest circuit breaker that can be installed for the branch circuit is ___ amps.
a.20 b.30 c.25 d.15 e.none of these a
A water heater has a nameplate rating of 5 KW @ 230 volts. This water heater will draw ___ amperes when operated at the rated voltage.
a.21.74 RWH = Erated2÷ Prated = (230)2÷ 5000 = 10.58 IWH = Ea÷ RWH = 230 ÷ 10.58 = 21.7391 A b.20.83 c.46.0 d.19.69 e.22.68 Feedback The correct answer is: 21.74
The Code section that specifies that the rating of any one cord-and-plug-connected utilization equipment (not fastened in place) shall not exceed 16 amps for a 20-amp branch circuit is ___. Select N/A (not applicable) if there is not a Code reference for this.
a.210.23(A)(1) 2020 NEC: 210.23(A)(1) b.230.208(B) c.404.14(A)(3) d.210.23(A)(2) e.N/A
NEC® Article ___ includes a section that covers using a cord and plug as a disconnecting means for a clothes dryer.
a.220 b.300 c.210 d.422 2020 NEC: 422.33(A)
Refer to Figure 112.711. With voltmeter leads placed in the "hot" and neutral slots on the lower half of the receptacle, the meter should indicate a reading of ___ volts. Switch 1 is ON and Switch 2 is OFF.
a.240 b.0 c.24 d.120 Correct e.12 Feedback The correct answer is: 120
The nameplate on a 1Ø boiler (big water heater) indicates that it can be operated at either 240 or 480 volts. It contains two heating elements. Each element has a rating of 12.3 KW at 240 volts.Refer to Scenario 119.52. If correctly connected to a 240-volt circuit, ___ volts are applied to each element.
a.240 Correct b.0 c.480 d.208 e.120
The maximum permitted current rating of a portable appliance on a 30-ampere branch circuit is ___ amps.
a.30 b.15 c.16 d.12 e.24 30 x 80% = 24 A
A window (room) air conditioner is cord connected and a dedicated branch circuit will be run for the receptacle. The air conditioner will draw 19 amps. The smallest circuit breaker that can be installed for the circuit is ___ amps.
a.30 b.15 c.25 d.20 e.none of these c
A duct heater contains two heating elements. Each element is rated to deliver 14.5 KW at 240 volts. The nameplate on the duct heater indicates that it can be connected to either a 240- or 480-volt circuit. In this case, the supply circuit is 240 volts.For Scenario 125.103-240, ___ amps of current will flow through eachheating element.
a.30.2 b.120.8 c.33.1 d.60.4 e.66.2 d
Type ___ cord can be used on portable appliances.
a.SP-2 b.SJ c.SO d.any of these d
The Hazard Communication Standard gives you the right to know about hazards in the workplace.
a.True b.False a
The white conductor contained in a 12/2 with ground MC cable can be marked with purple tape where visible or accessible and used for a traveler from a 3-way switch.
a.True b.False a
When running cable for 12-volt door chime systems, the length of the cable should be as short as possible to keep the voltage at the chime close to its rating.
a.True b.False a
Figure 124.108 Refer to the switch diagram shown in Figure 124.108. The HEATER can be turned ON with the HTR switch when the FAN switch is OFF.
a.True b.False b
Figure 124.109 Refer to the switch diagram shown in Figure 124.109. The NIGHT LIGHT is ON only when the LAMP is OFF.
a.True b.False b
Figure 124.110 Refer to the switch diagram shown in Figure 124.110. The FAN can be turned ON only when the LAMP is ON. a.True
a.True b.False b
One conduit threaded into the hub of a conduit body (such as an LB) is considered adequate support where the hub and the conduit are the same size.
a.True 2020 NEC: 314.23(E) Exc b.False
___-circuit lighting track will have five metal strips running the length of the track. Three metal strips will be on one side of the track for connection to one or two circuit neutrals and the ground. Two metal strips will be on the opposite side of the track for connection to the two circuit "hot" or ungrounded conductors.
a.Two b.Three a
In the EWR residence, the attic exhaust fan is ___ driven.
a.direct b.belt a
Three loads are connected to a 208 v circuit. L1- rated for 8.7 smps when operated at 240v L2- rated for 1.3 kW if operated at 230v L3-will consume 1340 watts at 250 vf
a.5.11 R2 = [Erated]2÷ Prated = (230)2÷ 1300 = 40.6923 then: I2 = Eapplied ÷ R2 = 208 ÷ 40.6923 = 5.1115 A b.6.25 c.176.9 d.5.65 e.40.7
On the EWR plans, at total of ___ heat detectors are shown in the house.
a.6 b.4 c.3 d.1 b
A circuit has 4 identical loads connected in parallel. The circuit voltage is 277 volts and the total connected load draws 11.2 amperes of current. The resistance of each of the identical loads is ___ ohms
a.6.18 b.1.48 c.24.73 d..45 e.98.93 correct answer: e. RT = Ea÷ IT = 277 ÷ 11.2 = 24.7321 ohmsR1 = R2 =R3 =R4 =RT× 4 = 24.7321 × 4 = 98.93 ohms
Figure 119.565 Refer to Figure 119.565. All lamps are type mr 16 and are rated at 50 watts when operated at 12 volts AC. An MR 16 is a type of low voltage lamp. The power used by each lamp is ___ watts.
a.600 b.12 c.200 d.16 e.50 e
The NEC® requirement that "each electric appliance shall be provided with a nameplate giving the identifying name and the rating in volts and amperes, or in volts and watts" is located in Article ___.
a.680 b.422 Correct c.410 d.230 Feedback The correct answer is: 422
Which NEC® Article covers the installation of wiring and equipment for fire alarm systems?
a.680 b.760 c.725 d.690 b
When direct-burial Type UF or USE cables are installed beneath concrete sidewalks or other concrete-paved areas for residential occupancies, they are required to be ___.I. installed in racewaysII. GFCI protectedIII. installed a minimum of 18 in. deep
a.I and II only b.I, II & III c.II only d.I and III only e.III only Sidewalks and paved areas would indicate paving that would never be less than 2 inches in thickness. Col 1, Row 2 f.II and III only
Which of the following are types of flexible cords?I. SJO II. SOW III. SO
a.I only b.I, II & III c.I & II only d.I & III only e.III only b
The fewest number of 20-amp, 120-volt bathroom branch circuits permitted to be installed for bathroom receptacles in a restaurant is ___. There is one bathroom for men and one for women.
a.0 2020 NEC: 210.11(C)(3) N/A b.1 c.2 d.3
Scenario 119.52The nameplate on a 1Ø boiler (big water heater) indicates that it can be operated at either 240 or 480 volts. It contains two heating elements. Each element has a rating of 12.3 KW at 240 volts.Refer to Scenario 119.52. When properly connected to a 480-volt circuit, ___ amps will flow through each element in the boiler.
a.128.125 b.51.25 correct c.82 d.94.17 e.102.5 R1 = [E(rated)]2 / P(rated) = [240 volts]2 / 12300 = 4.6829 ohms = R2R(total)= R1 + R2 = 4.6829 + 4.6829 = 9.3659 then: I1 = I(total) = E(applied) / R(total) = 480 / 9.3659 = 51.25 A
A 3-gang switch box is to be constructed using metal device (switch) boxes. The box assembly will contain two three-ways and one dimmer switch. External connectors will be used on the AC cables entering the box. The AC does NOT contain a ground. Three 14-3 cables plus one 14-2 enter the box assembly. The shallowest boxes you can use are ___" deep.
a.2 b.31/2 c.23/4 d.21/2 e.21/4 d
Figure 119.103 Refer to Figure 119.103 for the plan view of a bedroom in a new house. A receptacle must be installed no farther than ___ feet from the left edge of wall space .
a.2 b.6 c.4 d.12 b
If cable is to be installed for separate switching to a heat/fan/light combination, how many conductors must be in the cable including a grounding conductor?
a.2 wires b.3 wires c.5 wires d.4 wires c
Figure 112.711Refer to Figure 112.711. With Switch 2 ON and voltmeter leads placed between the switch terminals (on Switch 2), the meter should indicate a reading of ___ volts.
a.240 b.24 c.0 Correct d.120 e.12 Feedback The correct answer is: 0
Types of flexible cords are listed in Table ___.
a.310.15(B)(16) b.400.5 c.402.3 d.400.4 d
120/240 v 3-ph, 4-w. washing machine- 7.2 amps @220 v shirt press- 1800w @230 volts clothes dryer-5000 watts @250 v As shown in Figure 119.575, several pieces of laundromat equipment are to be connected to a 208-volt circuit. The total current (IT) drawn by all the loads is ___ amps.
a.35.03 b.40.31 c.35.86 d.30.52 IT = Iwm + Isp + Icd = 30.5248 amps e.39.12
Section ___ of the NEC® states that a central heating system must be supplied by an individual branch circuit.
a.422.12 b.218.9 c.210.9 d.350.8(A) a
What is the minimum VA rating of a transformer used to supply power to a chime that has a rating of 23 watts?
a.5 b.10 c.15 d.20 e.30 e
The nameplate on a 1Ø boiler indicates that it can be connected to either a 240- or 480-volt circuit. In this case, the supply circuit is 240 volts. It contains two heating elements. Each element has a rating of 16.2 kW at 240 volts. A boiler is simply a large water heater.For Scenario 125.101-240, the boiler will supply ___ watts of power.
a.8,100 b.16,200 c.64,800 d.32,400 d
What NEC® Article covers Community Antenna and Television and Radio Distribution?
a.820 b.800 c.760 d.810 a
The NEC® defines a Signaling Circuit in ___.
a.Article 100 b.725.1 c.725.10(C) d.800.3(B)(2) a
Figure 116.305 A 12-volt trolling motor on a boat is powered by two 12-volt batteries. Refer to Figure 116.305. Which connection diagram shows the batteries correctly connected to the trolling motor?
a.I only b.II only c.either I or II d.neither I nor II a
Which of the following is your responsibility on a jobsite?I. Watch out for the hazards you might place in the path or work area of your co-workers. II. Make sure you are performing your task in a safe manner.III. Wear PPE when required.
a.II & III only b.I only c.I & II only d.II only e.I, II & III e
If ___, electronic dimmers can be connected to an energized circuit.I. the switch leg is connected before connecting the ungrounded conductorII. the ungrounded conductor is connected before connecting the switch leg a.II only
a.II only b.I only c.neither I nor II d.either I or II c
An electrician looks for ___ on an air-conditioner nameplate to determine the minimum size branch circuit conductors he can use to supply power to the unit.
a.MOCP b.MCA b
In the living room (Re: EWR Drawing 9), do the fixed glass panels count as wall space?
a.No, if they are removable. b.Yes, if they slide open. c.Yes. Correct d.No, if they are expensive.
OSHA permits extension cords to be spliced if ___ is wrapped around the splice.
a.Scotch 33 electrical tape b.friction tape c.8 mil 600-volt adhesive pads d.any of these e.none of these. correct
A circuit is energized. When you touch the probes (leads) of a voltmeter across the terminals of a single-pole switch that is in the ON position, you are putting a very, very high resistance in parallel with the switch.
a.True Correct b.False Feedback The correct answer is: True
Figure 124.108 Refer to the switch diagram shown in Figure 124.108. The NIGHT LIGHT is ON only when the LAMP is OFF.
a.True b.False a
Figure 124.109 Refer to the switch diagram shown in Figure 124.109. The NIGHT LIGHT is ON constantly, regardless of any switch position.
a.True b.False a
Figure 124.110 Refer to the switch diagram shown in Figure 124.110. The NIGHT LIGHT is ON only when the LAMP is OFF.
a.True b.False a
One, two, or three circuit lighting track is available.
a.True b.False a
Table 300.5 in the NEC® permits a 120-volt, 15-amp, residential, underground circuit to be buried as shallow as 13 inches below grade, when the wiring method is ___ and the circuit is GFCI-protected.
a.UF Cable b.RMC c.PVC d.any of these Correct
Is it permitted to connect the metal frame of the attic exhaust fan to the grounded conductor?
a.Yes b.No b
Track lighting ___ be installed in wet or damp locations, where subject to physical damage, or in concealed locations.
a.can b.cannot b
Defective tools are ___ and should not be used.
a.costly b.expensive c.dangerous Correct d.none of these Feedback The correct answer is: dangerous
Compared to using corded tools, cordless tools provide ___ productivity.
a.decreased b.eliminated c.adjusted d.increased Correct Feedback The correct answer is: increased
The NEC® ___ permit the cord-and-plug connection from a range to a receptacle to be used as the disconnecting means.
a.does b.does not a
The NEC® ___ the branch-circuit conductors for a range to be sized at less than the nameplate rating of the range.
a.does permit b.does not permit a
For most dishwashers, the motor and heating element for drying are referred to in the NEC® at 220.60 as ___ loads because they do not operate simultaneously. This heating element is NOT the booster heating element.
a.exclusive b.reciprocating c.noncoincident d.alternating c
Operating a 240-volt water heater (or other resistive load) at 208 volts will result in ____ heat output (in watts) and a ____ life.
a.higher, shorter b.lower, longer Correct c.lower, shorter d.higher, longer Feedback The correct answer is: lower, longer
A GFCI receptacle ___ permitted to be located directly behind a freezer in a residential garage.
a.is b.is not 2020 NEC: 210.8
On the EWR plan for the first floor, the chime is located in the ___.
a.kitchen b.garage c.living room d.rear hall d
On the EWR plans, the water pump is located in the ___.
a.kitchen b.living room c.workshop Correct d.garage Feedback The correct answer is: workshop
A solenoid valve is used on the gas supply to a furnace. When energized by a control circuit, the valve is ___.
a.open b.closed a
The nameplate on a 1Ø boiler (big water heater) indicates that it can be connected to either a 240- or 480-volt circuit. In this case, the supply circuit is 480 volts. It contains two heating elements. Each element has a rating of 11.3 KW at 240 volts.For Scenario 125.102-480, the elements in will be connected in ___.
a.parallel b.series b
Using a power tool with a broken ground prong is ___ permitted.
a.seldom b.never Correct c.occasionally d.always Feedback The correct answer is: never
Two 12-volt batteries would be connected in ___ to deliver the correct voltage to a 12-volt load.
a.series b.parallel b
Which of the following are permitted to serve as the disconnecting means for a food-waste disposer?
a.the branch-circuit breaker b.a wall switch that disconnects the ungrounded conductor c.a receptacle and cord arrangement d.any of these e.none of these d
Never pile material in such a way that it will endanger a worker. Points to think about include ___.
a.the strength of the support if you're piling material on a floor, platform, or scaffold b.the stability of the ground if you're piling a heavy load c.the height of the pile so it won't topple d.all of these d
Electronic dimmers can be connected to an energized circuit if ___.
a.the switch leg is connected first b.the ungrounded conductor is connected first c.either a or b d.neither a nor b d
On EWR Drawing 9, the curved lines in the living room represent ___.
a.wiring methods b.switch legs correct c.wall position d.telephone lines
When using a powder-actuated tool to shoot into material, flying nails, fragments, concrete chips, and the like cause a hazard on the other side of the material. Make sure that ___.
a.you have first tested the safety devices b.nobody is in this area c.you use the proper charge for the tool d.all of these d