Arizona ROC C-11/CR-11 Electrical (Commercial) Examination

A 480-volt, three-phase commercial feeder supplies a balanced load drawing 85 amperes at a power factor of 0.88 lagging. What is the total real power consumed by this three-phase load in kilowatts (kW)?

• A70.7 kW
• B62.2 kW
• C35.9 kW
• D40.8 kW

A 480V, 3-phase, 3-wire branch circuit feeds a continuous load of 60 A over a distance of 250 feet. If THHN copper conductors with a circular mil area of 26,240 CM (1 AWG) are used, what is the calculated voltage drop assuming a K-factor of 12.9?

• A7.3 V
• B12.7 V
• C14.7 V
• D25.4 V

In a 480Y/277-volt, 3-phase AC system, what is the peak-to-peak voltage of the line-to-neutral sinusoidal waveform?

• A391.7 V
• B678.8 V
• C554.0 V
• D783.5 V

A 75 kVA, 3-phase step-down transformer has a 480V delta primary and a 208Y/120V wye secondary. What is the maximum full-load secondary line current rating?

• A208.2 A
• B90.2 A
• C156.1 A
• D360.6 A

A series circuit operating at 60 Hz contains a 15-ohm resistance, an inductive reactance of 25 ohms, and a capacitive reactance of 17 ohms. What is the total impedance (Z) of the circuit?

• A25.0 ohms
• B57.0 ohms
• C17.0 ohms
• D19.8 ohms

Under NEC 2017 Table 220.12, what is the minimum unit load per square foot required when calculating the general lighting load for a commercial office building?

• A3.0 VA per sq ft
• B2.0 VA per sq ft
• C3.5 VA per sq ft
• D1.0 VA per sq ft

When calculating the feeder load for commercial kitchen equipment under NEC 2017 Table 220.56, what demand factor is applied when four (4) commercial kitchen appliances are installed?

• A80%
• B100%
• C90%
• D70%

A commercial feeder supplies a continuous lighting load of 48 A and a non-continuous power load of 32 A. Under NEC 2017 Article 215.2(A)(1), what is the minimum required total ampacity rating of the feeder conductors?

• A80 A
• B100 A
• C92 A
• D108 A

Under NEC 2017 Article 230.24(A), service-drop conductors passing over a commercial roof with a slope of less than 4 inches in 12 inches must maintain a minimum vertical clearance of how many feet above the roof surface?

• A8 feet
• B3 feet
• C10 feet
• D12 feet

Under NEC 2017 Article 230.95, ground-fault protection of equipment (GFPE) is mandatory for solid-grounded wye commercial electrical services operating at more than 150 volts to ground but not exceeding 600 volts phase-to-phase when the service disconnect rating is at least what ampere threshold?

• A800 amperes
• B1200 amperes
• C600 amperes
• D1000 amperes

When sizing commercial multi-family or laundromat feeder demand for four (4) commercial electric clothes dryers under NEC 2017 Table 220.54, what demand factor percentage is used?

• A95%
• B90%
• C100%
• D85%

Under NEC 2017 Article 210.8(B), Ground-Fault Circuit-Interrupter (GFCI) protection is required for single-phase 125-volt 15- and 20-ampere commercial receptacles installed in which of the following locations?

• ACommercial kitchens, rooftops, and outdoors
• BExecutive carpeted private offices
• CDry commercial storage rooms
• DServer room dedicated equipment racks

What is the maximum recommended total voltage drop percentage across feeder and branch circuit conductors combined for reasonable efficiency of operation under NEC 2017 Informational Notes 215.2(A) and 210.19(A)?

• A10% total (5% branch circuit, 5% feeder)
• B3% total (2% branch circuit, 1% feeder)
• C5% total (3% branch circuit, 2% feeder)
• D8% total (4% branch circuit, 4% feeder)

Under NEC 2017 Article 230.71(A), what is the maximum number of switches or circuit breakers permitted as the service disconnecting means for each service at a single commercial location?

• A2 disconnects
• B4 disconnects
• C6 disconnects
• D8 disconnects

In a commercial office building, general receptacle outlets are connected to 120-volt branch circuits. Under NEC 2017 Section 220.14(I), what volt-ampere (VA) rating must be calculated for each single or multiple receptacle strap?

• A90 VA
• B360 VA
• C180 VA
• D150 VA

Under NEC 2017 Article 210.4(B), what safety requirement applies to all multi-wire branch circuits supplying equipment in commercial buildings?

• AEach ungrounded conductor must have an individual independent neutral conductor run in se…
• BMeans must be provided at the panelboard to simultaneously disconnect all ungrounded cond…
• CMulti-wire branch circuits are strictly prohibited in commercial buildings
• DThe neutral conductor must be sized at 200% of the ungrounded conductor ampacity

As a general rule under NEC 2017 Section 230.2, how many services are permitted to supply a single commercial building or structure?

• ATwo services
• BOne service
• CUnrestricted number of services
• DUp to six services

A commercial service consists of 3/0 AWG copper ungrounded service-entrance conductors. Under NEC 2017 Table 250.66, what is the minimum size copper Grounding Electrode Conductor (GEC) required?

• A6 AWG copper
• B2 AWG copper
• C1/0 AWG copper
• D4 AWG copper

A commercial feeder is protected by a 400-ampere overcurrent protective device. Under NEC 2017 Table 250.122, what is the minimum size copper Equipment Grounding Conductor (EGC) required in the raceway?

• A1 AWG copper
• B4 AWG copper
• C2 AWG copper
• D3 AWG copper

Under NEC 2017 Article 250.52(A)(3), a concrete-encased electrode (Ufer ground) must consist of at least how many feet of electrically conductive steel reinforcing bars or bare copper conductor?

• A10 feet
• B20 feet
• C8 feet
• D25 feet

When a single rod grounding electrode does not have a resistance to ground of 25 ohms or less under NEC 2017 Article 250.53(A)(2), a supplemental electrode must be installed. What is the minimum required separation distance between the two ground rods?

• A8 feet
• B6 feet
• C10 feet
• D3 feet

Under NEC 2017 Article 250.30(A)(1), where is the system bonding jumper for a separately derived commercial transformer system permitted to be connected?

• AAt any single point from the source to the first system disconnecting means, but not at b…
• BAt both the transformer enclosure and the main distribution panel simultaneously
• CExclusively at the load termination outlet
• DOnly at the utility meter enclosure

Under NEC 2017 Article 250.68(C)(1), interior metal water piping is permitted to be used as a grounding electrode conductor extension only within what distance from its point of entrance to the building?

• A10 feet
• B5 feet
• C3 feet
• D15 feet

Ungrounded circuit conductors rated 100 A are upsized from 3 AWG copper to 1/0 AWG copper (an increase in circular mil area from 52,620 CM to 105,600 CM, double the size) to compensate for voltage drop. Under NEC 2017 Article 250.122(B), how must the copper equipment grounding conductor (originally 8 AWG copper, 16,510 CM) be adjusted?

• AIt can remain at 8 AWG copper because overcurrent device size did not change
• BIt must be upsized to 1/0 AWG copper to match the ungrounded conductors
• CIt can be reduced to 10 AWG copper
• DIt must be upsized proportionally in circular mil area to approximately 6 AWG copper (33,…

Under NEC 2017 Article 250.102(C)(1), supply-side bonding jumpers for commercial service raceways must be sized based on Table 250.102(C)(1). What is the minimum size copper supply-side bonding jumper for a service with 500 kcmil copper ungrounded conductors?

• A2 AWG copper
• B2/0 AWG copper
• C3/0 AWG copper
• D1/0 AWG copper

Under NEC 2017 Article 250.118(5), flexible metal conduit (FMC) is permitted to serve as the sole equipment grounding conductor only when the trade size does not exceed 1-1/4 inches, the total ground return path length does not exceed 6 feet, and the circuit overcurrent protection is rated at or below what ampere limit?

• A30 amperes
• B20 amperes
• C50 amperes
• D15 amperes

Under NEC 2017 Article 250.104(C), exposed structural metal building framework that is likely to become energized must be bonded to which of the following?

• AAn isolated ground rod driven outside the building footprint
• BThe branch circuit neutral conductor at the nearest receptacle
• CThe telecom ground busbar only
• DThe service equipment enclosure, grounded conductor at the service, or grounding electrod…

Under NEC 2017 Article 250.64(B), a 6 AWG copper grounding electrode conductor (GEC) that is not subject to physical damage must be installed in which manner?

• AEnclosed in Schedule 80 PVC or rigid metal conduit in all cases
• BRigidly attached to the building surface following the building contour
• CBuried at a minimum depth of 36 inches under concrete
• DSuspended freely from ceiling grid wires

Under NEC 2017 Article 250.92(B), electrical continuity of metallic service raceways containing service conductors must be ensured by which of the following bonding methods?

• AStandard locknuts on painted concentric knockouts without bonding jumpers
• BFriction fit set-screw fittings without grounding bushings
• CSheet metal screws driven into conduit fittings
• DThreaded couplings/hubs, or bonding locknuts/bushings with bonding jumpers

Under NEC 2017 Table 310.15(B)(16), what is the allowable ampacity of a 3/0 AWG THHN copper conductor operating in a 75°C terminal rating environment?

• A225 amperes
• B200 amperes
• C175 amperes
• D150 amperes

Seven (7) current-carrying THHN copper conductors are installed in a single raceway. Under NEC 2017 Table 310.15(B)(3)(a), what adjustment factor percentage must be applied to the conductors' 90°C ampacity rating?

• A70%
• B80%
• C50%
• D60%

Commercial conductors in raceways exposed to direct sunlight on a rooftop in Phoenix, Arizona are installed 1 inch above the roof deck. Under NEC 2017 Table 310.15(B)(3)(c), what temperature adder must be added to the outdoor ambient temperature?

• A40°F (22°C)
• B30°F (17°C)
• C20°F (11°C)
• D15°F (8°C)

Under NEC 2017 Section 110.14(C)(1)(a), equipment termination provisions for circuits rated 100 amperes or less (or marked for 14 AWG through 1 AWG conductors) shall be based on conductor ampacities evaluated at what temperature column rating, unless listed otherwise?

• A75°C (167°F)
• B90°C (194°F)
• C60°C (140°F)
• D105°C (221°F)

Under NEC 2017 Section 330.30, Type MC (Metal-Clad) cable must be supported and secured at intervals not exceeding how many feet, and within how many inches of every box, cabinet, or fitting?

• A4.5 feet intervals, within 12 inches of box
• B10 feet intervals, within 24 inches of box
• C6 feet intervals, within 12 inches of box
• D8 feet intervals, within 18 inches of box

Under NEC 2017 Section 334.12(A)(1), Nonmetallic-Sheathed Cable (Type NM) is prohibited from being installed in which of the following commercial applications?

• AIn single-story commercial retail buildings
• BInside dry wooden stud partitions
• CIn any structure or building exceeding three stories above grade, or in Types I and II no…
• DAbove dropped lay-in grid ceilings in 1-story buildings

Under NEC 2017 Table 300.5, what is the minimum cover depth required for direct-buried Type UF cable installed under a commercial parking lot subject to heavy vehicular traffic?

• A18 inches
• B24 inches
• C12 inches
• D36 inches

Under NEC 2017 Section 310.106(A), what is the minimum conductor size permitted for general wiring up to 2000 volts?

• A12 AWG copper / 10 AWG aluminum
• B16 AWG copper / 14 AWG aluminum
• C10 AWG copper / 8 AWG aluminum
• D14 AWG copper / 12 AWG aluminum

Under NEC 2017 Article 310.15(B)(5)(c), when must the neutral conductor of a 4-wire, 3-phase wye circuit supplying commercial LED lighting or computer power supplies be counted as a current-carrying conductor for ampacity derating?

• AIn all 3-phase wye circuits regardless of connected load type
• BOnly when the circuit overcurrent device rating exceeds 200 amperes
• CWhen the major portion of the load consists of non-linear loads producing triplen harmoni…
• DNever; neutral conductors are always exempt from current-carrying conductor counts

Under NEC 2017 Section 400.12, flexible cords and cables are prohibited from being used in which of the following commercial applications?

• ATo connect portable commercial appliances
• BFor wiring of cranes and hoists
• CTo facilitate frequent interchange of commercial display equipment
• DAs a substitute for the fixed wiring of a structure, or run through holes in walls, struc…

Under NEC 2017 Table 300.5, what is the minimum required cover depth for Rigid Metal Conduit (RMC) containing commercial branch circuits buried under a commercial driveway?

• A18 inches
• B24 inches
• C6 inches
• D12 inches

Under NEC 2017 Chapter 9, Table 1, what is the maximum allowable percentage of cross-sectional area fill permitted for a raceway containing more than two (2) conductors?

• A31%
• B40%
• C53%
• D60%

A metallic outlet box contains two 12 AWG conductors terminating on a duplex receptacle, two 12 AWG conductors spliced through, internal cable clamps, and one equipment grounding conductor. Under NEC 2017 Section 314.16(B), what is the total volume allowance required for this box?

• A18.0 cubic inches
• B13.5 cubic inches
• C15.75 cubic inches
• D20.25 cubic inches

Under NEC 2017 Section 314.28(A)(1), for straight pulls of conductors 4 AWG or larger, what is the minimum required length of a pull box containing 3-inch trade size conduits?

• A18 inches
• B24 inches
• C30 inches
• D36 inches

A commercial pull box contains angle pulls for 4 AWG conductors. The wall of the box has entries for one 3-inch conduit and two 2-inch conduits. Under NEC 2017 Section 314.28(A)(2), what is the minimum required distance between that box wall and the opposite wall?

• A18 inches
• B22 inches
• C24 inches
• D28 inches

Under NEC 2017 Section 358.30(A), Electrical Metallic Tubing (EMT) must be securely fastened within how many feet of each outlet box, junction box, or fitting, and at support intervals not exceeding how many feet?

• AWithin 3 feet of box; support every 10 feet
• BWithin 5 feet of box; support every 10 feet
• CWithin 3 feet of box; support every 8 feet
• DWithin 2 feet of box; support every 12 feet