Arizona ROC R-11 Electrical (Residential) Examination

An electrical technician measures a 120-volt residential branch circuit supplying a fixed heating element with a measured resistance of 15 ohms. According to Ohm's Law (V = I x R), what is the current flowing through this heating element?

• A8 amperes
• B10 amperes
• C12 amperes
• D15 amperes

A 240-volt single-phase residential electric water heater element draws a continuous current of 18.75 amperes. Using Watt's Law (P = V x I), what is the power rating of this heating element?

• A3,600 watts
• B4,500 watts
• C5,000 watts
• D5,400 watts

Three resistive loads with resistances of 10 ohms, 20 ohms, and 20 ohms are connected in parallel across a single-phase AC circuit. What is the total equivalent resistance of this parallel combination?

• A5 ohms
• B10 ohms
• C15 ohms
• D50 ohms

A single-phase residential step-down transformer has a primary winding connected to 2,400 volts AC and a secondary winding rated at 120 volts AC. If the primary winding has 2,000 turns, how many turns are on the secondary winding?

• A50 turns
• B100 turns
• C200 turns
• D400 turns

In North American residential AC power systems operating at a standard frequency of 60 Hertz (Hz), what is the time period (T) required to complete one full AC sine wave cycle?

• A0.00833 seconds (8.33 ms)
• B0.01667 seconds (16.67 ms)
• C0.03333 seconds (33.33 ms)
• D0.06000 seconds (60.00 ms)

An inductor with an inductance of 0.05 Henrys is connected to a standard 60 Hz residential AC line. What is the inductive reactance (Xl) of this inductor in ohms? (Use pi = 3.1416)

• A3.00 ohms
• B9.42 ohms
• C18.85 ohms
• D37.70 ohms

A capacitor rated at 100 microfarads (100 uF) is connected to a 60 Hz AC voltage source. What is the capacitive reactance (Xc) of this capacitor in ohms? (Use pi = 3.1416)

• A13.26 ohms
• B26.53 ohms
• C37.70 ohms
• D53.05 ohms

What term defines the ratio of real power (measured in kilowatts, kW) to apparent power (measured in kilovolt-amperes, kVA) in an alternating current (AC) circuit?

• APower factor
• BForm factor
• CEfficiency ratio
• DDiversity factor

A single-phase 240-volt AC electric motor load draws 20 amperes at a lagging power factor of 0.85. What is the real power consumed by this motor in kilowatts (kW)?

• A4.08 kW
• B4.80 kW
• C5.65 kW
• D8.16 kW

Which of the following physical factors will INCREASE the electrical resistance of a metallic conductor?

• AIncreasing the cross-sectional circular mil area of the conductor
• BDecreasing the length of the conductor
• CIncreasing the operating temperature of a copper conductor
• DPlacing identical conductors in parallel

A combination circuit consists of a 10-ohm resistor connected in series with a parallel branch containing two 20-ohm resistors. If this circuit is connected across a 120-volt DC source, what is the total current drawn from the supply?

• A2.4 amperes
• B4.0 amperes
• C6.0 amperes
• D12.0 amperes

A single-phase utility pad-mounted transformer supplying a residential service is rated at 50 kVA with a 120/240-volt secondary output. What is the maximum full-load secondary current available at 240 volts?

• A104.2 amperes
• B208.3 amperes
• C416.7 amperes
• D500.0 amperes

An oscilloscope measures a standard 120-volt AC (RMS) sinusoidal residential voltage. What is the peak voltage (Vpeak) of this sine wave?

• A84.8 volts
• B120.0 volts
• C169.7 volts
• D240.0 volts

A residential feeder conductor has a total loop resistance of 0.15 ohms and carries a continuous load current of 30 amperes. How much power is lost as heat in this feeder? (P = I^2 x R)

• A4.5 watts
• B67.5 watts
• C135.0 watts
• D270.0 watts

When connecting inductive loads (such as large air-conditioner compressor motors) to a residential electrical system, what impact does a lower power factor have on line current and system efficiency?

• ALine current decreases, reducing conductor I^2 R heating losses
• BLine current remains unchanged regardless of power factor
• CLine current increases for the same real kW power delivered, increasing voltage drop and…
• DLine voltage increases above system rated peak levels

Under NEC Article 220, what is the calculated net general lighting and small appliance demand load for a single-family dwelling with 2,400 sq ft of living space, containing two 20A small appliance circuits and one 20A laundry circuit?

• A4,845 VA
• B6,045 VA
• C11,700 VA
• D14,040 VA

According to NEC Table 220.55, what is the feeder demand load for a single household electric range rated at 12 kW?

• A5.0 kW (5,000 VA)
• B8.0 kW (8,000 VA)
• C9.6 kW (9,600 VA)
• D12.0 kW (12,000 VA)

A dwelling unit features a single household electric range with a nameplate rating of 16 kW. Pursuant to NEC Table 220.55 Note 1, what is the calculated demand load for sizing feeder conductors?

• A8.0 kW
• B9.6 kW
• C11.2 kW
• D16.0 kW

What is the minimum feeder demand load required by NEC 220.54 for a single electric clothes dryer installed in a dwelling unit if the dryer nameplate rating is 4,200 VA?

• A3,500 VA
• B4,200 VA
• C5,000 VA
• D6,000 VA

Under NEC 220.61, what is the feeder neutral demand load for a 120/240V single-phase dwelling service supplying a general lighting demand of 6,000 VA, a 12 kW range (8,000 VA demand), and a 5,000 VA electric dryer?

• A15,100 VA
• B19,000 VA
• C13,300 VA
• D9,100 VA

Using the Optional Calculation method for a single-family dwelling (NEC 220.82), a 2,000 sq ft house has general lighting (6,000 VA), two small appliance circuits (3,000 VA), one laundry circuit (1,500 VA), an 8,000 VA range demand, a 5,000 VA dryer, and a 1,500 VA dishwasher. Total connected general load is 25,000 VA. What is the demand load for these general loads before adding HVAC?

• A10,000 VA
• B16,000 VA
• C17,500 VA
• D25,000 VA

A flush-mounted metal device box contains four 12 AWG THHN insulated conductors, two 12 AWG bare equipment grounding conductors, internal cable clamps, and one duplex receptacle connected to the 12 AWG conductors. Under NEC 314.16(B), what is the minimum internal box volume required?

• A13.5 cubic inches
• B15.75 cubic inches
• C18.0 cubic inches
• D20.25 cubic inches

An outlet box contains six 14 AWG THHN insulated conductors, three 14 AWG bare equipment grounding conductors, internal cable clamps, and one single-pole toggle switch. According to NEC 314.16(B), what is the minimum box volume required?

• A16.0 cubic inches
• B18.0 cubic inches
• C20.0 cubic inches
• D22.0 cubic inches

Six 10 AWG THHN copper current-carrying conductors are installed in a single continuous raceway in a 30 degree C ambient temperature environment. If the 90 degree C ampacity of 10 AWG THHN copper is 40 amperes (2017 NEC Table 310.15(B)(16)), what is the adjusted ampacity under 2017 NEC Table 310.15(B)(3)(a)?

• A28 amperes
• B32 amperes
• C35 amperes
• D40 amperes

An 8 AWG THHN copper conductor (90 degree C ampacity = 55 A) is installed in an attic where the ambient temperature reaches 40 degrees C (104 degrees F). According to 2017 NEC Table 310.15(B)(2)(a), what is the temperature-corrected ampacity of this conductor?

• A44.0 amperes
• B50.05 amperes
• C55.0 amperes
• D60.5 amperes

Four current-carrying 6 AWG THHN copper conductors (90 degree C rating = 75 A) are routed through a conduit in an outdoor ambient temperature of 40 degrees C (104 degrees F). Applying both temperature correction (0.91) and conduit bundle derating (0.80), what is the allowable derated ampacity?

• A54.6 amperes
• B60.0 amperes
• C68.25 amperes
• D75.0 amperes

A 120-volt single-phase 15A continuous branch circuit uses 12 AWG solid copper conductor (K = 12.9, circular mil area CM = 6,530) to supply a load located 100 feet from the panelboard. What is the calculated line voltage drop? (Formula: VD = [2 x K x I x L] / CM)

• A2.96 volts
• B5.93 volts
• C7.41 volts
• D11.85 volts

What is the maximum circuit length permitted for a 240-volt single-phase 30-ampere electric clothes dryer circuit using 10 AWG copper conductor (K = 12.9, CM = 10,380) if line voltage drop must not exceed the NEC recommended 3% limit (7.2 volts)?

• A72.4 feet
• B96.5 feet
• C124.8 feet
• D193.1 feet

Using NEC Chapter 9 Tables 1, 4, and 5, what is the maximum number of 12 AWG THHN copper conductors (approximate area = 0.0133 sq in each) permitted to be installed in a trade size 1/2-inch Electrical Metallic Tubing (EMT, 40% fill area = 0.122 sq in)?

• A5 conductors
• B7 conductors
• C9 conductors
• D12 conductors

According to NEC Chapter 9, Note 4 to Tables, what maximum percentage of total internal cross-sectional area fill is permitted when clean conduit nipples not exceeding 24 inches (600 mm) in length are installed between enclosures?

• A31 percent
• B40 percent
• C53 percent
• D60 percent

A single-phase 230-volt 2 HP residential pool pump motor has a Full-Load Current (FLC) rating of 12.0 amperes from NEC Table 430.248. According to NEC 430.22, what is the minimum ampacity required for the branch-circuit conductors supplying this motor?

• A12.0 amperes
• B15.0 amperes
• C18.0 amperes
• D24.0 amperes

For a single-phase 230V 2 HP motor with an FLC rating of 12.0 amperes, what is the maximum standard rating permitted for an inverse-time circuit breaker used as short-circuit and ground-fault protection under NEC 430.52 and Table 430.52?

• A15 amperes
• B20 amperes
• C30 amperes
• D40 amperes

A central air conditioning unit has a manufacturer nameplate showing a Minimum Circuit Ampacity (MCA) of 28.5 amperes and a Maximum Overcurrent Protective Device (MOPD) rating of 45 amperes. What is the minimum copper conductor size (75 degree C rating) and maximum breaker size required?

• A10 AWG copper conductor and 30A circuit breaker
• B10 AWG copper conductor and 45A circuit breaker
• C8 AWG copper conductor and 45A circuit breaker
• D8 AWG copper conductor and 50A circuit breaker

A residential branch circuit supplies a continuous lighting load of 16 amperes and a noncontinuous load of 4 amperes. Pursuant to NEC 210.19(A)(1), what is the minimum required rating for the branch-circuit overcurrent protective device?

• A20 amperes
• B24 amperes
• C25 amperes
• D30 amperes

Under NEC 314.28(A)(2), what is the minimum length required for a junction box containing 4 AWG conductors where an angle pull is made through a 2-inch trade size conduit?

• A8 inches
• B12 inches
• C14 inches
• D16 inches

Per NEC 230.79(C), what is the minimum required ampere rating for the main service disconnecting means installed for a single-family dwelling?

• A60 amperes
• B100 amperes
• C125 amperes
• D200 amperes

Under 2017 NEC Table 310.15(B)(7), what minimum size copper service-entrance conductors are permitted for a 120/240-volt single-phase 200-ampere main service supplying a single-family dwelling?

• A1 AWG copper
• B1/0 AWG copper
• C2/0 AWG copper
• D3/0 AWG copper

According to NEC 210.11(C)(1), what is the minimum number of 20-ampere small-appliance branch circuits required to serve receptacle outlets in the kitchen, pantry, breakfast room, and dining room of a residential dwelling?

• AOne 20A circuit
• BTwo 20A circuits
• CThree 20A circuits
• DFour 20A circuits

Under NEC 210.11(C)(2), at least one dedicated 20-ampere branch circuit must be provided in a dwelling unit to supply receptacle outlets in which of the following areas?

• AThe master bedroom closet
• BThe laundry area
• CThe dining room lighting
• DThe foyer

Pursuant to NEC 210.11(C)(3), a 20-ampere bathroom branch circuit supplying receptacles in a dwelling unit is permitted to serve lighting and equipment in that same bathroom ONLY IF which condition is met?

• AThe circuit supplies receptacles in multiple bathrooms
• BThe circuit supplies only a single bathroom
• CThe branch circuit breaker is rated 30 amperes
• DThe lighting outlet is controlled by a dimmer switch

According to NEC 210.52(A)(1), wall receptacle outlets in dwelling unit habitable rooms must be installed so that no point measured horizontally along the floor line in any wall space is more than how many feet from a receptacle outlet?

• A4 feet
• B6 feet
• C8 feet
• D12 feet

Under NEC 210.52(C)(1), receptacle outlets installed along dwelling kitchen wall countertop spaces must be located so that no point along the wall line is more than how far horizontally from a receptacle outlet?

• A12 inches
• B18 inches
• C24 inches
• D48 inches

Under 2017 NEC 210.52(C)(2), what is the receptacle requirement for a dwelling kitchen island countertop that measures 60 inches long by 30 inches wide with no sink or cooktop installed in it?

• AAt least one receptacle outlet is required, because the countertop is at least 24 inches…
• BNo receptacle outlet is required, but a junction box must be provided for a future outlet
• CAt least three receptacle outlets are required, one for each 18 square feet of countertop
• DReceptacle outlets are prohibited in island countertops because of cord hazards

Per NEC 210.52(E)(1), a single-family dwelling unit requires at least how many outdoor receptacle outlets accessible at grade level at the front and back of the dwelling?

• AAt least one at the front and one at the back
• BOnly one total near the main entrance
• COne every 20 feet along the exterior perimeter
• DOutdoor receptacles are optional

In dwelling units, hallways of what minimum length measured along the centerline without passing through a doorway require at least one receptacle outlet under NEC 210.52(H)?

• A6 feet or more
• B10 feet or more
• C12 feet or more
• D15 feet or more

According to NEC 210.63, a 125-volt, single-phase 15- or 20-ampere receptacle outlet must be installed for servicing heating, air-conditioning, and refrigeration (HACR) equipment within what maximum distance of the equipment?

• A6 feet
• B10 feet
• C25 feet
• D50 feet