Nevada C-2 Electrical Contractor Examination

A balanced 480-volt, three-phase load draws 72 amperes at a lagging power factor of 0.86. What is the real power of this load?

• A29.7 kW
• B51.5 kW
• C59.9 kW
• D69.1 kW

A 120-volt, single-phase, 2-wire branch circuit supplies a 16-ampere load. The one-way conductor length is 100 feet of 12 AWG copper (K = 12.9, area = 6,530 CM). What is the calculated voltage drop?

• A3.16 volts
• B5.47 volts
• C10.39 volts
• D6.32 volts

A series 60 Hz circuit has 12 ohms of resistance, 20 ohms of inductive reactance, and 11 ohms of capacitive reactance. What is the impedance of the circuit?

• A15.0 ohms
• B9.0 ohms
• C21.9 ohms
• D43.0 ohms

A 45 kVA, three-phase transformer has a 480-volt delta primary and a 208Y/120-volt secondary. What is the full-load secondary line current?

• A54.1 A
• B93.6 A
• C216.3 A
• D124.9 A

On a 480Y/277-volt system, what is the peak (zero-to-peak) value of the line-to-neutral sine wave?

• A196 V
• B277 V
• C679 V
• D392 V

A 240/120-volt, three-phase, 4-wire delta service has a high-leg. What is the voltage from the high-leg to the grounded conductor, and how must that phase be identified in the panelboard?

• A208 volts, identified orange and placed on phase B
• B120 volts, identified white
• C240 volts, identified yellow and placed on phase C
• D277 volts, identified brown and placed on phase A

Which formula correctly converts a 208-volt, three-phase, 18-kilowatt balanced load at 0.90 power factor into line current?

• AI = 18,000 / 208
• BI = 18,000 / (208 × 0.90)
• CI = 18,000 / (1.732 × 208)
• DI = 18,000 / (1.732 × 208 × 0.90)

A 480-volt, three-phase feeder carries 80 amperes over 250 feet of 2 AWG copper (K = 12.9, area = 66,360 CM). What is the percent voltage drop?

• A1.40 percent
• B0.81 percent
• C1.62 percent
• D2.80 percent

Under NEC 2017 Table 220.12, what unit lighting load is used for a general lighting calculation in an office building?

• A1 VA per square foot
• B2 VA per square foot
• C3 VA per square foot
• D3.5 VA per square foot

For a standard dwelling-unit service calculation, NEC 220.52 requires which minimum small-appliance and laundry branch-circuit loads?

• ATwo 1,500 VA small-appliance circuits and one 1,500 VA laundry circuit
• BOne 1,500 VA small-appliance circuit and no laundry circuit
• CTwo 1,800 VA receptacle circuits and one 1,200 VA laundry circuit
• DThree 2,000 VA kitchen circuits and one 20-ampere bathroom circuit only

A 2,400-square-foot dwelling has a 3 VA per square foot general lighting load, two 1,500 VA small-appliance circuits, and one 1,500 VA laundry circuit (11,700 VA total). After NEC Table 220.42 demand factors, what is the net general lighting and appliance demand?

• A6,045 VA
• B7,350 VA
• C8,700 VA
• D11,700 VA

Four 12 kW household electric ranges are calculated under NEC Table 220.55 Column C. What demand load is used?

• A17 kW
• B24 kW
• C28 kW
• D48 kW

Using the NEC 220.82 optional dwelling calculation, a 2,800-square-foot dwelling has two small-appliance circuits, one laundry circuit, a 12 kW range, a 4.5 kW water heater, and a 5 kW dryer (34,400 VA of general load) plus a 6,720 VA air conditioner that is the largest HVAC load. What is the total calculated load?

• A16,480 VA
• B19,760 VA
• C41,120 VA
• D26,480 VA

A 208-volt, single-phase feeder supplies an 80-ampere continuous load and no noncontinuous load. What is the minimum conductor ampacity required by NEC 215.2(A)(1)?

• A80 A
• B96 A
• C125 A
• D100 A

In a dwelling living room, NEC 210.52(A) requires receptacle outlets so that no point along the floor line of a wall space is more than how far from a receptacle?

• A6 feet
• B4 feet
• C8 feet
• D12 feet

A 6,000-square-foot office has a Table 220.12 lighting load plus 30 duplex receptacles calculated at 180 VA each. No other loads apply. What is the three-phase line current at 208Y/120 volts for this calculated load?

• A58.3 A
• B73.3 A
• C65.0 A
• D127.0 A

NEC 230.79(C) requires the service disconnecting means for a one-family dwelling to have a rating of not less than:

• A100 amperes
• B60 amperes
• C125 amperes
• D200 amperes

A 120/240-volt service uses 3/0 AWG copper ungrounded service-entrance conductors. What is the minimum copper grounding electrode conductor required by NEC Table 250.66?

• A4 AWG copper
• B6 AWG copper
• C2 AWG copper
• D1/0 AWG copper

What is the minimum copper equipment grounding conductor for a 200-ampere feeder, using NEC Table 250.122?

• A6 AWG copper
• B8 AWG copper
• C4 AWG copper
• D3 AWG copper

A single 8-foot ground rod is driven as the only made electrode and the measured resistance to earth is 40 ohms. What does NEC 250.53(A)(2) require?

• AThe rod must be supplemented by an additional electrode unless the single electrode is 25…
• BThe rod is acceptable because any single rod is permitted without a resistance limit
• CThe rod must be replaced with a concrete-encased electrode
• DThe rod must be increased to 5/8 inch diameter only

A metal underground water pipe qualifies as a grounding electrode under NEC 250.52(A)(1) only if it is in direct contact with the earth for:

• A5 feet or more
• B8 feet or more
• C20 feet or more
• D10 feet or more

Which installation meets the NEC 250.52(A)(3) concrete-encased electrode (Ufer) requirements?

• A20 feet of bare 4 AWG copper encased in at least 2 inches of concrete near the bottom of…
• B10 feet of 6 AWG bare copper laid on top of the footing
• C8 feet of 1/2-inch rebar stubbed out of the slab solely for the GEC clamp
• D20 feet of 8 AWG insulated copper run in the wall cavity above the footing

A 120/240-volt service is made up of two parallel sets of 250 kcmil copper ungrounded conductors. What is the minimum copper grounding electrode conductor?

• A1/0 AWG copper
• B2 AWG copper
• C2/0 AWG copper
• D3/0 AWG copper

A 200-ampere feeder uses 3/0 AWG copper ungrounded conductors (167,800 CM) that are increased to 250 kcmil (250,000 CM) for voltage drop. The original Table 250.122 EGC is 6 AWG copper (26,240 CM). What is the minimum copper EGC after applying NEC 250.122(B)?

• A4 AWG copper
• B6 AWG copper
• C3 AWG copper
• D2 AWG copper

At a 120/240-volt dwelling service, the main bonding jumper in the service disconnect enclosure is required to connect which of the following?

• AThe grounded service conductor to the service-equipment enclosure and the equipment groun…
• BThe grounding electrode conductor only to the metal water pipe
• CThe ungrounded service conductors to building steel
• DThe feeder neutrals to each subpanel enclosure

A 480-volt delta to 208Y/120-volt wye transformer is a separately derived system. Where must the system bonding jumper be installed?

• AAt the source or the first disconnecting means of the derived system, but not at both unl…
• BAt any convenient downstream panel on the 208-volt secondary
• COnly at the utility transformer on the 480-volt primary
• DAt every 208-volt receptacle yoke

According to NEC 2017 Table 310.15(B)(16), what is the allowable ampacity of 4 AWG THWN copper in a raceway, not more than three current-carrying conductors, 30°C ambient, using the 75°C column?

• A85 A
• B70 A
• C95 A
• D115 A

Unless an exception in 240.4 applies, NEC 240.4(D) limits a 12 AWG copper conductor to overcurrent protection of not more than:

• A20 A
• B15 A
• C25 A
• D30 A

Unless the equipment is listed and identified for use at higher temperatures, NEC 110.14(C)(1) requires conductor ampacity to be selected from the 60°C column for which terminations?

• ACircuits rated 100 amperes or less, or marked for 14 AWG through 1 AWG conductors
• BAll terminations, regardless of size
• COnly service-entrance lugs on a 400-ampere switchboard
• DOnly aluminum conductors larger than 4/0 AWG

Six current-carrying 8 AWG THHN copper conductors are installed in one EMT at 30°C. Starting from the 90°C ampacity of 55 A, what is the adjusted ampacity under Table 310.15(B)(3)(a)?

• A27.5 A
• B38.5 A
• C50.0 A
• D44.0 A

The allowable ampacity of Type NM-B cable shall not exceed that of a 60°C rated conductor under NEC 334.80. For 12 AWG copper NM-B, that 60°C value is:

• A20 A
• B15 A
• C25 A
• D30 A

Six current-carrying 4 AWG THHN copper conductors are installed in one raceway in a 40°C ambient. Terminations are 75°C. Using the 90°C ampacity of 95 A, a 0.91 ambient correction from Table 310.15(B)(2)(a), and an 80-percent adjustment from Table 310.15(B)(3)(a), what allowable ampacity results?

• A55 A
• B85 A
• C76 A
• D69 A

A 4-wire, 208Y/120-volt feeder consists of three phase conductors and a neutral that serves a heavy fluorescent lighting load (nonlinear). For Table 310.15(B)(3)(a), how is the neutral counted?

• AThe neutral is never a current-carrying conductor
• BThe equipment grounding conductor is counted instead of the neutral
• COnly the two phase conductors with the highest current are counted
• DThe neutral is counted as a current-carrying conductor because it carries third-harmonic…

NEC 310.10(H) generally permits conductors to be connected in parallel only when each paralleled phase, neutral, or grounded conductor is at least:

• A4 AWG
• B1 AWG
• C250 kcmil
• D1/0 AWG

For a 120/240-volt, single-phase dwelling service rated 200 amperes, NEC 2017 Table 310.15(B)(7) permits which minimum ungrounded and neutral service conductors?

• A1 AWG copper or 2/0 AWG aluminum
• B1/0 AWG copper or 3/0 AWG aluminum
• C3/0 AWG copper or 250 kcmil aluminum
• D2/0 AWG copper or 4/0 AWG aluminum

A 240-volt, single-phase feeder supplies 40 amperes over a one-way length of 180 feet. Using K = 12.9 for copper, what is the smallest conductor that keeps voltage drop from exceeding 3 percent (7.2 V)? Circular-mil areas: 8 AWG = 16,510; 6 AWG = 26,240; 4 AWG = 41,740; 3 AWG = 52,620.

• A8 AWG copper
• B3 AWG copper
• C4 AWG copper
• D6 AWG copper

Using NEC Chapter 9, Table 4 and Table 5 (40 percent fill, more than two conductors), how many 12 AWG THHN conductors are permitted in 3/4-inch EMT? (3/4-inch EMT 40 percent area = 0.213 in²; 12 AWG THHN area = 0.0133 in².)

• A9
• B12
• C22
• D16

NEC Table 314.16(B) requires what volume allowance for each 12 AWG conductor counted in a box-fill calculation?

• A2.00 cubic inches
• B3.00 cubic inches
• C2.50 cubic inches
• D2.25 cubic inches

According to NEC Table 314.16(A), what is the minimum internal volume of a 4-inch square metal box that is 1-1/2 inches deep?

• A15.5 cubic inches
• B18.0 cubic inches
• C30.3 cubic inches
• D21.0 cubic inches

Unless listed for a greater interval, EMT shall be securely fastened in place at intervals not exceeding which distances in NEC 358.30(A)?

• AWithin 12 inches of each box and every 4-1/2 feet thereafter
• BOnly at each box; intermediate supports are not required
• CWithin 5 feet of each box and every 15 feet thereafter
• DWithin 3 feet of each outlet box, junction box, cabinet, or conduit body and every 10 fee…

Four 1/0 AWG THHN copper conductors are installed in EMT (more than two conductors, 40 percent fill). Each 1/0 THHN has an approximate area of 0.1855 in². What is the smallest EMT listed below that meets Chapter 9, Table 4?

• A1 inch (40 percent = 0.346 in²)
• B1-1/4 inch (40 percent = 0.598 in²)
• C2 inch (40 percent = 1.342 in²)
• D1-1/2 inch (40 percent = 0.814 in²)

According to NEC Table 352.30, rigid PVC conduit trade sizes 1/2 inch through 1 inch shall be supported at intervals not exceeding:

• A3 feet
• B5 feet
• C8 feet
• D10 feet

A pull box is used for an angle pull of 4 AWG and larger conductors. Two 2-inch raceways and one 3-inch raceway enter the same wall and leave an adjacent wall. What is the minimum distance from that wall to the opposite wall under NEC 314.28(A)(2)?

• A18 inches
• B32 inches
• C24 inches
• D22 inches