California CSLB C-10 Electrical Examination

A 2,400 sq ft single-family dwelling unit requires a standard service load calculation per CEC Article 220. The general lighting (3 VA/sq ft), two small appliance circuits (1,500 VA each), and one laundry circuit (1,500 VA) total 11,700 VA before demand factors. What is the net calculated demand load for these combined general lighting and appliance loads after applying CEC Table 220.42 demand factors?

• A6,045 VA
• B7,110 VA
• C8,700 VA
• D9,250 VA

A single-phase 240V branch circuit supplies a 20A continuous load across a one-way length of 150 feet using 10 AWG solid copper conductors (K = 12.9, circular mil area = 10,380 CM). What is the estimated line-to-line voltage drop for this run?

• A4.85 volts
• B7.46 volts
• C9.92 volts
• D12.3 volts

A balanced 480V three-phase commercial feeder supplies a 100A continuous load over a distance of 300 feet using 1/0 AWG THHN copper conductors (K = 12.9, circular mil area = 105,600 CM). What is the approximate percentage voltage drop for this feeder?

• A0.85 percent
• B2.45 percent
• C1.32 percent
• D3.68 percent

An electrical contractor is calculating the main feeder demand load for a multi-family building with four 12 kW household electric ranges. According to CEC Table 220.55 Column C, what is the total maximum demand load for these four ranges?

• A48 kW demand
• B28 kW demand
• C24 kW demand
• D17 kW demand

When calculating feeder and service loads for commercial kitchen equipment under CEC Table 220.56, what demand factor applies to a facility equipped with six (6) thermostatically controlled commercial electric kitchen appliances?

• A65 percent
• B70 percent
• C80 percent
• D100 percent

On architectural electrical plans, what does a wall switch symbol labeled with a subscript '3' ('S3') represent?

• AA single-pole switch with a 3-amp rating
• BA three-way switch controlling a luminaire
• CA three-pole switch for three-phase equipment
• DA smart switch requiring a neutral conductor

According to CEC Chapter 9, Table 1, what is the maximum allowable percentage conduit fill for cross-sectional area when installing three or more conductors of any size in a single raceway?

• A31 percent
• B53 percent
• C40 percent
• D60 percent

An estimator calculates that installing 400 feet of 3/4-inch Electrical Metallic Tubing (EMT) exposed on concrete walls requires 1.5 labor hours per 100 feet. If the electrician's fully burdened labor rate is $85/hour, what is the estimated total direct labor cost for this conduit installation?

• A340 dollars
• B425 dollars
• C480 dollars
• D510 dollars

Under California Title 24, Part 6 (Building Energy Efficiency Standards), what mandatory indoor lighting control requirement applies to nonresidential office spaces greater than 100 square feet?

• AOccupants must have manual controls plus automatic shut-off controls
• BLighting must operate continuously during business hours without switches
• CAll luminaires must be hardwired directly to emergency backup batteries
• DOnly dimmable LED fixtures operating below 12 volts may be installed

A commercial building main service supplies a continuous non-lighting load of 160A and a non-continuous load of 80A. Per CEC 215.3 and 230.42, what is the minimum required rating for the service-entrance conductors and overcurrent device (assuming standard 75°C terminations)?

• A240 amperes
• B280 amperes
• C300 amperes
• D320 amperes

What minimum kVA rating is required for a three-phase 480V to 208Y/120V dry-type transformer supplying a continuous secondary load of 180 amperes?

• A45.0 kVA
• B50.0 kVA
• C64.8 kVA
• D75.0 kVA

What is the primary purpose of calculating available short-circuit current (fault current) at a commercial electrical main service panelboard prior to installation?

• ATo ensure the main service disconnect matches the utility transformer secondary voltage
• BTo calculate the total monthly kilowatt-hour energy consumption of the facility
• CTo select overcurrent protective devices with an adequate Interrupting Rating (AIC)
• DTo determine the minimum number of branch circuit breakers permitted per panel

An industrial facility operates a 100 kW inductive load at a lagging power factor of 0.70. How many reactive kilovars (kVAR) of power factor correction capacitors are needed to raise the system power factor to 0.95?

• A69 kVAR
• B85 kVAR
• C102 kVAR
• D142 kVAR

Under CEC Article 210.20, how must a branch circuit overcurrent protective device be sized when supplying a load that operates continuously for three hours or more?

• AAt 100 percent of the continuous load rating
• BAt 125 percent of the continuous load rating
• CAt 150 percent of the continuous load rating
• DAt 200 percent of the continuous load rating

Under California Business and Professions Code Section 7159 (CSLB Home Improvement Contracts), what is the maximum down payment a C-10 contractor may legally collect prior to starting work on a residential contract?

• A50 percent of the total contract price
• B25 percent of the contract price or $2,500
• C10 percent of contract price or $1,000, whichever is less
• D15 percent of contract price or $1,500, whichever is less

When pulling feeder conductors through rigid conduit runs containing bends, what parameter must be monitored to prevent physical damage to conductor insulation at elbow turns?

• AAmbient copper resistance factor
• BConductor temperature rise index
• CDielectric insulation breakdown voltage
• DSidewall bearing pressure (SWBP)

Under California Title 24, Part 6 energy standards, what is the default maximum automatic shut-off time delay allowed for occupancy sensors controlling indoor lighting in commercial spaces?

• A20 minutes
• B30 minutes
• C45 minutes
• D60 minutes

According to CEC Article 690.7, how is the maximum photovoltaic (PV) system DC source circuit voltage calculated for equipment sizing in low-temperature environments?

• ABy using nominal array voltage without modification
• BBy multiplying rated Voc by low-temp correction factor
• CBy dividing total array wattage by system inverter current
• DBy taking 125 percent of the maximum power voltage Vmp

An Electric Vehicle Supply Equipment (EVSE) station is rated for a 48-amp continuous output. Per CEC Article 625.42, what minimum branch-circuit conductor ampacity and overcurrent protection device rating are required?

• A48 amperes
• B50 amperes
• C60 amperes
• D70 amperes

Per CEC Article 408.36, what overcurrent protection requirement applies to lighting and appliance branch-circuit panelboards installed in commercial buildings?

• APanelboards do not require individual overcurrent protection if fed from sub-feed lugs
• BIndividual protection is required only if panelboards contain more than 42 circuit breake…
• COvercurrent protection may be rated up to 150 percent of panelboard busbar ampacity
• DPanelboards must be protected on supply side by device not exceeding busbar rating

A flush-mounted metal device box with internal cable clamps contains two 12 AWG THHN copper conductors, two 12 AWG conductors connected to a duplex receptacle, and two equipment grounding conductors. Per CEC Table 314.16(B), what is the minimum required internal box volume?

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

Under the optional calculation method for multi-family dwellings in CEC 220.84, what demand factor is applied to the combined feeder load of a 20-unit apartment building?

• A50 percent
• B38 percent
• C45 percent
• D60 percent

A feeder supplies three 3-phase, 460V induction motors with Full-Load Currents (FLC) of 28A, 40A, and 50A. According to CEC 430.24, what is the minimum ampacity required for the feeder conductors?

• A118 amperes
• B125 amperes
• C130.5 amperes
• D147.5 amperes

An electrical plan drawn to an architectural scale of 1/4 inch = 1 foot shows a continuous branch circuit conduit run measuring 6.5 inches on paper. What is the actual physical distance in the field?

• A16.25 feet
• B22.0 feet
• C24.5 feet
• D26.0 feet

Under CEC Article 700.12, what is the maximum allowable time delay for an emergency standby generator system to automatically restore power to emergency illumination loads upon loss of primary utility power?

• A10 seconds
• B30 seconds
• C60 seconds
• D120 seconds

According to CEC Table 300.5, what is the minimum burial cover depth required for direct-buried Type UF cable installed under a commercial driveway subject to vehicular traffic?

• A18 inches
• B24 inches
• C12 inches
• D30 inches

A packaged air conditioning unit has a rated-load current of 32A for the hermetic motor-compressor and 4A for the fan motor. Per CEC 440.33, what is the Minimum Circuit Ampacity (MCA) required for branch circuit conductor selection?

• A36 amperes
• B40 amperes
• C44 amperes
• D48 amperes

An electrical contractor estimates direct job costs (materials and labor) for a commercial remodel at $50,000. Overhead is 15 percent of direct costs, and target profit is 10 percent of total bid price. What is the total required bid price?

• A57,500 dollars
• B62,500 dollars
• C63,250 dollars
• D63,889 dollars

According to CEC Table 310.15(C)(1), what ampacity adjustment factor must be applied to current-carrying conductors when eight (8) current-carrying conductors are installed in the same raceway?

• A70 percent
• B80 percent
• C50 percent
• D45 percent

What ambient temperature correction factor applies per CEC Table 310.15(B)(1) for THHN copper conductors (90°C rating column) installed in a room with an ambient temperature of 45°C (113°F)?

• A0.91 factor
• B0.87 factor
• C0.82 factor
• D0.71 factor

Under CEC Table 250.66, what is the minimum size copper Grounding Electrode Conductor (GEC) required for a service supplied by 2/0 AWG copper service-entrance conductors?

• A8 AWG copper
• B6 AWG copper
• C4 AWG copper
• D2 AWG copper

According to CEC Table 250.122, what is the minimum required copper Equipment Grounding Conductor (EGC) size for a feeder protected by a 200-ampere overcurrent protective device?

• A10 AWG copper
• B8 AWG copper
• C4 AWG copper
• D6 AWG copper

According to CEC 358.26, what is the maximum total equivalent bend angle permitted between outlet boxes or pull fittings in a single continuous run of Electrical Metallic Tubing (EMT)?

• A360 degrees
• B270 degrees
• C180 degrees
• D540 degrees

When sizing a pull box for a straight pull containing 3-inch trade size raceways entering with conductors 4 AWG or larger, what is the minimum required box length per CEC 314.28(A)(1)?

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

According to CEC 330.30, what is the maximum permitted spacing between supports for Type MC (Metal-Clad) cable, and what is the maximum distance from an outlet box to the first support?

• ASupports every 4.5 feet and within 6 inches of box
• BSupports every 10 feet and within 24 inches of box
• CSupports every 6 feet and within 12 inches of box
• DSupports every 8 feet and within 18 inches of box

Per CEC 334.30, Type NM-B (nonmetallic-sheathed) cable must be secured within what distance from an outlet box without cable clamps, and at what maximum intervals along wood framing members?

• AWithin 6 inches of box and supports every 6.0 feet
• BWithin 18 inches of box and supports every 3.0 feet
• CWithin 12 inches of box and supports every 5.0 feet
• DWithin 12 inches of box and supports every 4.5 feet

Per CEC 348.30, Flexible Metal Conduit (FMC) must be secured by an approved means within what maximum distance from each box, cabinet, or conduit termination point?

• A12 inches
• B18 inches
• C24 inches
• D36 inches

According to CEC 250.52(A)(3), what are the concrete-encased electrode ('Ufer' ground) specification requirements for steel reinforcing bars installed in a building foundation?

• AMinimum 10 feet of 3/8-inch bare steel rebar encased in 1 inch of concrete only
• BMinimum 20 feet of 1/2-inch rebar or 4 AWG bare copper near bottom of footing
• CMinimum 15 feet of galvanized steel pipe driven vertically into concrete
• DMinimum 30 feet of 2 AWG insulated copper conductor embedded in foundation

When driven ground rods are installed to form the grounding electrode system under CEC 250.53(A)(3), what minimum separation distance is required between two driven ground rods?

• A3 feet apart
• B4 feet apart
• C6 feet apart
• D10 feet apart

Under CEC 250.102(C)(1), how is the supply-side bonding jumper sized for service equipment where ungrounded service-entrance conductors exceed 1,100 kcmil copper?

• AFixed at 3/0 AWG copper regardless of the total kcmil area value only
• BSized at 20 percent of total ungrounded conductor area
• CSized from CEC Table 250.66 without area calculation
• DSized at not less than 12.5 percent of total ungrounded copper area

A 3-phase, 460V, 25 HP squirrel-cage induction motor has a full-load current (FLC) rating of 34A from CEC Table 430.250. What is the maximum permitted inverse-time circuit breaker rating for branch-circuit short-circuit protection per CEC Table 430.52?

• A85 amperes
• B100 amperes
• C70 amperes
• D125 amperes

According to CEC 430.32(A)(1), what is the maximum trip setting for separate motor overload protection devices for a continuous-duty motor with a nameplate Service Factor (SF) of 1.15?

• A115 percent of motor nameplate full-load current
• B125 percent of motor nameplate full-load current
• C140 percent of motor nameplate full-load current
• D150 percent of motor nameplate full-load current

Under CEC Table 450.3(B), what is the maximum primary overcurrent protection device rating for a 480V transformer rated over 9 amps with primary-only protection?

• A115 percent of rated primary current
• B150 percent of rated primary current
• C125 percent of rated primary current
• D250 percent of rated primary current

A 480V three-phase motor feeder supplies two continuous-duty induction motors: Motor A (FLC 40A) and Motor B (FLC 20A). What is the minimum required ampacity for the feeder conductors per CEC 430.24?

• A60 amperes
• B65 amperes
• C75 amperes
• D70 amperes