CSLB General Building (B) — All Questions

A one-family dwelling has 2,000 ft² of habitable floor area. Using the standard method, what is the general lighting and general-use receptacle load?

• a.6,000 VA✓
• b.4,000 VA
• c.9,000 VA
• d.3,000 VA

Dwelling general lighting is calculated at 3 VA/ft², so 2,000 ft² × 3 VA/ft² = 6,000 VA. 4,000 VA would use 2 VA/ft² (wrong value), and 3,000 VA is only the small-appliance/laundry portion, not general lighting.2023 NEC §220.41

In a dwelling load calculation, what minimum load must be included for the two required small-appliance branch circuits?

• a.1,500 VA
• b.3,000 VA✓
• c.4,500 VA
• d.2,000 VA

Each 20 A small-appliance branch circuit is figured at 1,500 VA, and at least two are required, so 2 × 1,500 = 3,000 VA. 1,500 VA covers only one circuit, and 4,500 VA would be three circuits.2023 NEC §220.52(A)

How much load must be included for the laundry branch circuit in a dwelling load calculation?

• a.1,000 VA
• b.3,000 VA
• c.1,500 VA✓
• d.750 VA

The laundry branch circuit is calculated at 1,500 VA. That is the same figure used per small-appliance circuit; 3,000 VA would be two circuits and the other values are not code-specified figures.2023 NEC §220.52(B)

The combined general lighting, small-appliance, and laundry load of a dwelling is 9,000 VA. After applying the standard-method demand factors, what is the net load?

• a.9,000 VA
• b.3,150 VA
• c.4,200 VA
• d.5,100 VA✓

The first 3,000 VA is taken at 100% and the remaining 6,000 VA at 35%: 3,000 + (6,000 × 0.35) = 3,000 + 2,100 = 5,100 VA. Applying 35% to the whole amount or forgetting the first block gives the wrong distractor values.2023 NEC §220.42

Using Table 220.55, Column C, what is the demand load for a single 12 kW household electric range?

• a.8 kVA✓
• b.12 kVA
• c.6.6 kVA
• d.10 kVA

For one range not over 12 kW, Column C gives a demand of 8 kVA. 12 kVA is the nameplate rating (no demand applied), so it is incorrect.2023 NEC §220.55

A household electric clothes dryer is rated 4.5 kW. What value is used in the service load calculation?

• a.4,500 VA
• b.5,000 VA✓
• c.5,500 VA
• d.3,500 VA

Dryers are calculated at 5,000 VA or the nameplate rating, whichever is greater. Since 4,500 VA is less than the 5,000 VA minimum, you must use 5,000 VA.2023 NEC §220.54

A dwelling calculated load totals 24,000 VA on a 240 V, single-phase service. What is the minimum service ampacity this load demands?

• a.60 A
• b.90 A
• c.100 A✓
• d.125 A

Amps = VA ÷ volts = 24,000 ÷ 240 = 100 A. Dividing by 120 or using the wrong voltage produces the other values, so the calculated demand is 100 A.

Using the optional method, a dwelling's other loads (excluding heating/AC) total 30 kVA. What is the demand after applying the optional-method demand factors?

• a.30 kVA
• b.22 kVA
• c.12 kVA
• d.18 kVA✓

The first 10 kVA is at 100% and the remainder at 40%: 10 + (20 × 0.40) = 10 + 8 = 18 kVA. Applying 40% to the whole 30 kVA or skipping the first block gives the wrong answers.2023 NEC §220.82(B)

On an electrical floor plan, the switch symbol marked with a subscript 3 (S3) indicates what device?

• a.A three-way switch✓
• b.A single-pole switch
• c.A switch rated 3 amperes
• d.Three switches ganged together

The subscript on a switch symbol denotes the switch type: S3 is a three-way switch used to control a load from two locations. A plain S is single-pole, and the subscript is not an ampere rating or a device count.

How often is a new edition of the National Electrical Code, on which the California Electrical Code is based, normally published?

• a.Every 2 years
• b.Every 3 years✓
• c.Every 5 years
• d.Every 10 years

The NEC is revised on a three-year cycle (e.g., 2017, 2020, 2023), and California adopts it with state amendments on a similar cycle. The other intervals do not match the code's revision schedule.

A floor plan is drawn at a scale of 1/4 in = 1 ft. A wall measures 3 in on the drawing. What is its actual length?

• a.3 ft
• b.6 ft
• c.12 ft✓
• d.48 ft

At 1/4 in = 1 ft, each inch equals 4 ft, so 3 in × 4 ft/in = 12 ft. Reading the drawing dimension directly (3 ft) or misapplying the scale gives the other values.

Which drawing best shows the vertical arrangement of the service and feeders as they run between floors of a multistory building?

• a.Floor plan
• b.Panel schedule
• c.Plot plan
• d.Riser diagram✓

A riser diagram is a schematic that shows service and feeder conductors rising vertically between floors and to panelboards. A floor plan shows horizontal layout, a panel schedule lists circuits, and a plot plan shows the site.

During the permit process, when is the rough (rough-in) electrical inspection normally performed?

• a.Before walls and ceilings are closed or covered✓
• b.After final paint is applied
• c.After the building is occupied
• d.Only when the contractor requests it

The rough inspection verifies boxes, wiring, and grounding while everything is still exposed, so it must occur before drywall or other finishes conceal the work. Inspecting after finishes would hide the very items being checked.

The optional calculation method of 220.82 may be used for a dwelling served by a single 120/240 V feeder or service rated at least how many amperes?

• a.60 A
• b.100 A✓
• c.200 A
• d.400 A

The optional method applies where the dwelling is served by a single 3-wire 120/240 V (or 3-phase, 4-wire) service or feeder rated 100 A or greater. Smaller values do not meet the threshold and 200 A/400 A are not the minimum.2023 NEC §220.82(A)

A 1,500 ft² dwelling's standard-method calculation yields 13,100 VA on 240 V (about 55 A). What is the minimum service disconnect rating required?

• a.60 A
• b.90 A
• c.100 A✓
• d.70 A

Even though the calculated demand is only about 55 A, a one-family dwelling service disconnect must be rated at least 100 A. The calculated load does not override the 100 A minimum, so the smaller ratings are not permitted.2023 NEC §230.79(C)

When four or more fastened-in-place appliances (other than the range, dryer, space heating, and air conditioning) are on the same feeder in a dwelling, what demand factor may be applied to their total nameplate load?

• a.100%
• b.50%
• c.80%
• d.75%✓

A demand factor of 75% is permitted where four or more such fastened-in-place appliances are served. With three or fewer, no reduction applies, so 100% would be used only in that case.2023 NEC §220.53

What is the minimum number of 20 A small-appliance branch circuits required to serve the kitchen, dining, and similar areas of a dwelling?

• a.2✓
• b.1
• c.3
• d.4

At least two 20 A small-appliance branch circuits are required for the kitchen, pantry, dining room, and similar areas. One is insufficient, and while more may be installed, two is the code minimum.2023 NEC §210.11(C)(1)

What unit load per square foot is used for general lighting in a dwelling unit?

• a.2 VA/ft²
• b.3 VA/ft²✓
• c.1.5 VA/ft²
• d.5 VA/ft²

Dwelling-unit general lighting and general-use receptacles are calculated at 3 VA/ft². The other values do not match the code figure for dwellings.2023 NEC §220.41

Which loads may be added to the general lighting load and then subjected together to the 220.42 general-lighting demand factors?

• a.The electric range load
• b.The clothes dryer load
• c.The small-appliance and laundry branch-circuit loads✓
• d.The HVAC load

The small-appliance (2 × 1,500 VA) and laundry (1,500 VA) loads are permitted to be added to the general lighting and taken together at the 220.42 demand factors. The range, dryer, and HVAC have their own separate demand rules.2023 NEC §220.52

A dwelling has 9,000 VA of electric heating and 6,000 VA of air conditioning that cannot operate at the same time. What value is included in the service calculation?

• a.15,000 VA
• b.3,000 VA
• c.7,500 VA
• d.9,000 VA✓

For noncoincident loads that cannot run simultaneously, only the larger load is included, which is the 9,000 VA of heating. Adding both (15,000 VA) or averaging them ignores the noncoincident rule.2023 NEC §220.60

A household range has a calculated demand of 8,000 VA. What maximum value may be used for the neutral (grounded) feeder load for this range?

• a.5,600 VA✓
• b.8,000 VA
• c.4,000 VA
• d.2,800 VA

The neutral load for a household range may be taken at 70% of the demand: 8,000 × 0.70 = 5,600 VA. Using the full 8,000 VA ignores the 70% allowance, and the other values apply wrong percentages.2023 NEC §220.61(B)

In electrical estimating, what does a labor unit represent?

• a.The purchase cost of the material
• b.The estimated labor-hours to install one unit of material✓
• c.The contractor's profit margin
• d.The permit fee for the job

A labor unit is the estimated time (usually in hours or hundredths of an hour) needed to install a single item such as a receptacle or a foot of conduit. Multiplying labor units by quantities gives total labor hours, which is separate from material cost, profit, or permits.

In the bidding process, what is a material takeoff?

• a.Removing old wiring from a building
• b.A change to the contract price
• c.Counting and listing all materials and devices from the drawings✓
• d.The final inspection of the job

A takeoff is the systematic counting and listing of every device, fitting, and length of material shown on the plans so quantities can be priced. It is not demolition, a change order, or an inspection.

Where is the California Electrical Code officially published within the California Code of Regulations?

• a.Title 8
• b.The NEC directly with no state code
• c.Title 19
• d.Title 24, Part 3✓

The California Electrical Code is Title 24, Part 3 of the California Code of Regulations, based on the NEC with California amendments. Title 8 covers worker safety (Cal/OSHA), and the CEC is a state adoption rather than the NEC used directly.

Which set of California regulations contains the worker-safety rules (Cal/OSHA) that apply to electricians on the job?

• a.Title 8✓
• b.Title 24
• c.NEC Chapter 8
• d.Title 20

Cal/OSHA occupational safety and health regulations are found in Title 8 of the California Code of Regulations. Title 24 is building/energy codes, NEC Chapter 8 covers communications systems, and Title 20 covers appliance efficiency.

Under the optional dwelling method, at what percentage is the nameplate rating of the air-conditioning equipment included in the heating/AC portion of the calculation?

• a.40%
• b.100%✓
• c.65%
• d.75%

In the optional method, air-conditioning is included at 100% of its nameplate rating (as one of the larger heating/AC selections). The 65% figure applies to certain central electric heating, and 40% is the optional method's general-load factor, not the AC factor.2023 NEC §220.82(C)

Using the optional method, a dwelling's 220.82(B) other loads (general lighting, appliances, etc., excluding heating/AC) sum to 40 kVA. What is the calculated demand for that portion?

• a.40 kVA
• b.16 kVA
• c.22 kVA✓
• d.18 kVA

Apply 100% to the first 10 kVA and 40% to the remainder: 10 + (30 × 0.40) = 10 + 12 = 22 kVA. Taking 40% of the entire 40 kVA (16 kVA) skips the first-10-kVA block.2023 NEC §220.82(B)

In the normal permit and inspection sequence, when is the final electrical inspection performed?

• a.Before rough-in wiring
• b.Before trenching for the service
• c.Before the panel is installed
• d.After all work is complete, before the system is used or occupied✓

The final inspection occurs after all devices, trim, and the panel are complete and just before the system is energized for use or the building is occupied. It is the last step, not something done before rough-in, trenching, or panel installation.

Who is normally responsible for obtaining the electrical permit for a project?

• a.The licensed contractor performing the work✓
• b.The serving electric utility
• c.The project architect
• d.The building inspector

The licensed contractor doing the installation normally pulls the permit and is responsible for the work being inspected. The utility connects power, the architect designs, and the inspector reviews the work rather than obtaining the permit.

What is the primary purpose of a single-line (one-line) diagram?

• a.To show every individual conductor in the building
• b.To represent the overall power distribution system using single lines✓
• c.To detail the internal wiring of each device
• d.To show the furniture layout of the floor

A one-line diagram uses single lines and standardized symbols to show the overall flow of power from the service through switchgear, panels, and major equipment. It intentionally omits individual conductor and device wiring detail.

What information does a panel schedule provide?

• a.The property boundary lines of the site
• b.The roof framing plan
• c.A list of branch circuits with their breaker sizes and connected loads✓
• d.The plumbing riser layout

A panel schedule lists each circuit number in a panelboard along with breaker size, the load it serves, and phase/pole information used for balancing and calculations. It is unrelated to site boundaries, roof framing, or plumbing.

For a branch circuit, what maximum voltage drop does the NEC recommend for reasonable efficiency?

• a.1%
• b.10%
• c.8%
• d.3%✓

An informational note recommends that branch-circuit voltage drop not exceed 3% (with a combined feeder-plus-branch limit of about 5%). This is a recommendation for efficiency, not an enforceable rule, and the larger values would cause excessive drop.

A dwelling's total calculated load is 44,000 VA on a 240 V service. What is the smallest standard service rating that will carry this load?

• a.200 A✓
• b.150 A
• c.175 A
• d.225 A

44,000 ÷ 240 = 183 A, so the service must be at least 183 A; the next standard size up is 200 A. A 150 A or 175 A service would be undersized for a 183 A demand.

Electric-vehicle supply equipment is considered a continuous load. At what percentage of its rating must the branch circuit and feeder be sized?

• a.100%
• b.125%✓
• c.80%
• d.150%

EVSE is a continuous load, so conductors and overcurrent devices are sized at 125% of the equipment rating. Sizing at only 100% ignores the continuous-load requirement, and 80% and 150% are not the applicable factors.2023 NEC §625.42

A continuous load (operating 3 hours or more) draws 16 A. What minimum overcurrent-device/conductor rating must serve it?

• a.16 A
• b.18 A
• c.20 A✓
• d.25 A

Continuous loads are multiplied by 125%: 16 A × 1.25 = 20 A. Sizing at the load itself (16 A) or by other factors does not satisfy the continuous-load rule, so 20 A is required.2023 NEC §210.20(A)

In a non-dwelling occupancy, 20 general-use receptacle outlets are installed. What load must be included for these receptacles?

• a.1,800 VA
• b.2,000 VA
• c.4,000 VA
• d.3,600 VA✓

Non-dwelling receptacle outlets are calculated at 180 VA each: 20 × 180 = 3,600 VA. Using 90 VA or 100 VA each would produce the smaller distractor values.2023 NEC §220.14(I)

A mercantile (store) occupancy has 5,000 ft² of floor area and a general lighting unit load of 3 VA/ft². What is the general lighting load?

• a.15,000 VA✓
• b.10,000 VA
• c.5,000 VA
• d.20,000 VA

5,000 ft² × 3 VA/ft² = 15,000 VA. Using 2 VA/ft² or 1 VA/ft² would give the smaller values, so 15,000 VA is correct for the 3 VA/ft² figure given.

A retail store has 10 linear feet of show-window lighting. Using the show-window unit load, what load must be included?

• a.1,000 VA
• b.2,000 VA✓
• c.3,000 VA
• d.1,800 VA

Show windows are calculated at 200 VA per linear foot: 10 ft × 200 VA = 2,000 VA. Using 100 VA/ft or 300 VA/ft gives the other values.2023 NEC §220.14(G)

For each commercial occupancy accessible to pedestrians, at least one outlet for a sign or outline lighting must be provided with a minimum circuit load of how many VA?

• a.600 VA
• b.900 VA
• c.1,200 VA✓
• d.1,500 VA

A sign/outline-lighting outlet must be computed at a minimum of 1,200 VA. The smaller figures do not meet the required minimum for this dedicated sign circuit.2023 NEC §220.14(F)

Branch-circuit conductors supplying a single continuous-duty motor must have an ampacity of at least what percentage of the motor full-load current?

• a.80%
• b.100%
• c.115%
• d.125%✓

Conductors to a single motor must be rated at least 125% of the motor's full-load current (from the NEC tables). Values below 125% would undersize the conductors for motor starting and running duty.2023 NEC §430.22

What does a plot (site) plan primarily show?

• a.The building's location on the property and site utilities✓
• b.The location of every receptacle in a room
• c.The panel schedule for a switchboard
• d.The internal wiring detail of a device

A plot or site plan shows the building footprint on the lot, property lines, and the routing of site utilities such as the service lateral. Receptacle locations, panel schedules, and device wiring appear on other sheets.

What does a detail drawing on a set of plans typically show?

• a.The entire site and all buildings
• b.An enlarged view of a specific component or connection✓
• c.The electrical utility bill
• d.The text of the electrical code

A detail is an enlarged, close-up drawing of a specific part such as a mounting bracket, a connection, or an equipment pad, so it can be built correctly. It is not a site overview, a bill, or code text.

When the drawings or specifications are unclear, what document does the contractor typically submit to the designer for clarification?

• a.A change order
• b.A permit application
• c.A request for information (RFI)✓
• d.A punch list

An RFI (request for information) is the formal way to ask the designer to clarify unclear or conflicting plan information. A change order alters price/scope, a permit application starts the permit, and a punch list itemizes final corrections.

A documented, agreed adjustment to the contracted scope of work and price is called what?

• a.A request for information
• b.A submittal
• c.A material takeoff
• d.A change order✓

A change order is the written, mutually agreed document that modifies the contract's scope and price. An RFI asks a question, a submittal proposes products for approval, and a takeoff counts materials.

Who typically performs the code-compliance inspections on a permitted electrical project?

• a.The local building department (AHJ) inspector✓
• b.The serving utility lineman
• c.The general contractor
• d.The electrician's helper

Inspections are carried out by the local building department inspector, who is the authority having jurisdiction (AHJ). The utility lineman connects power, and the contractor or helper performs the work but does not sign off the official inspection.

A dwelling's standard-method net calculated load is 28,600 VA on a 240 V service. What is the smallest standard service size that will carry it?

• a.100 A
• b.125 A✓
• c.150 A
• d.110 A

28,600 ÷ 240 = 119 A, so the service must exceed 119 A; the next standard size is 125 A. A 100 A or 110 A service would be too small for a 119 A demand.

Using Table 250.66, for copper service-entrance conductors of 3/0 AWG, what is the minimum size copper grounding electrode conductor?

• a.6 AWG
• b.8 AWG
• c.4 AWG✓
• d.2 AWG

Per Table 250.66, service conductors over 2/0 through 3/0 AWG copper require a 4 AWG copper grounding electrode conductor. 8 AWG serves 2 AWG or smaller, and 2 AWG GEC is for larger service conductors.2023 NEC §250.66

In a bid, what does overhead refer to?

• a.The direct material used on the job
• b.The direct labor installed on the job
• c.The profit added to the price
• d.Indirect business costs allocated to the job✓

Overhead is the indirect cost of running the business (office rent, insurance, vehicles, tools, administrative staff) that must be recovered across jobs. Direct material, direct labor, and profit are separate line items in a bid.

Estimators add a waste factor to material quantities to account for what?

• a.Material lost to cutting, scrap, and errors✓
• b.Overtime labor hours
• c.Permit fees
• d.Contractor profit

A waste factor increases ordered quantities to cover material that is cut off, scrapped, or mistakenly used so the job does not run short. It is not related to labor overtime, permit fees, or profit.

A home run is 60 ft long and pulls 3 conductors. Adding 10% for waste, approximately how much conductor should be ordered?

• a.180 ft
• b.198 ft✓
• c.60 ft
• d.540 ft

Wire length = 60 ft × 3 conductors = 180 ft, then × 1.10 for waste = 198 ft. Forgetting the three conductors (60 ft) or the waste (180 ft) gives the low distractors.

If a receptacle takes 0.5 labor-hour to install, how many labor-hours should be estimated to install 30 receptacles?

• a.30 hours
• b.60 hours
• c.15 hours✓
• d.7.5 hours

Labor = 30 units × 0.5 hr = 15 labor-hours. Multiplying by 2 (60) or by the count alone (30) misapplies the labor unit, and 7.5 uses the wrong quantity.

Using the optional method, a dwelling's 220.82(B) loads compute to 19,280 VA, plus 5,000 VA of air conditioning at 100%. On a 240 V service (about 101 A), what is the minimum standard service size?

• a.100 A
• b.150 A
• c.175 A
• d.125 A✓

Total = 19,280 + 5,000 = 24,280 VA; 24,280 ÷ 240 = 101 A. Since the demand exceeds 100 A, the next standard size, 125 A, is required. A 100 A service would be slightly undersized.2023 NEC §220.82

The California Electrical Code is essentially the NEC as modified by what?

• a.California state amendments✓
• b.Local utility company rules
• c.IEEE standards
• d.UL product listings

California adopts each NEC edition and then modifies it with California-specific amendments to create the CEC (Title 24, Part 3). Utility rules, IEEE standards, and UL listings are separate documents, not what creates the CEC.

In code language, what does the abbreviation AHJ stand for?

• a.Approved Housing Judge
• b.Authority Having Jurisdiction✓
• c.Annual Home Inspection
• d.American Home Journal

AHJ means Authority Having Jurisdiction, the office or official responsible for enforcing the code and approving equipment and installations. The other choices are not code terms.

For a set of service-entrance conductors, the service disconnecting means is generally limited to a maximum of how many switches or circuit breakers?

• a.2
• b.4
• c.6✓
• d.8

The service disconnecting means is limited to a maximum of six switches or circuit breakers for a given set of service conductors. Modern code also requires them to be in separate enclosures, but the six-disconnect limit still governs.2023 NEC §230.71

The 2023 NEC requires one- and two-family dwellings to have an emergency disconnect installed where?

• a.It is not required
• b.Inside the dwelling only
• c.In the attic
• d.At a readily accessible outdoor location✓

An emergency disconnect must be installed in a readily accessible outdoor location so first responders can shut off power. It is required, and an interior or attic location would not meet the readily accessible outdoor requirement.2023 NEC §230.85

For 120/240 V equipment likely to require examination while energized (Condition 1), what is the minimum depth of working space in front of it?

• a.3 ft✓
• b.2 ft
• c.4 ft
• d.1 ft

Under Condition 1, the minimum working-space depth for equipment operating at 0-150 V to ground is 3 ft. Two feet or one foot is too little, and 4 ft applies to higher-voltage or worse conditions.2023 NEC §110.26(A)(1)

What is the minimum width of working space in front of electrical equipment (or the width of the equipment, whichever is greater)?

• a.24 in
• b.30 in✓
• c.36 in
• d.18 in

The working space must be at least 30 in wide, or the width of the equipment, whichever is greater. Narrower dimensions such as 24 in or 18 in do not meet the minimum.2023 NEC §110.26(A)(2)

What is the minimum headroom (height) of working space about electrical equipment such as panelboards?

• a.6 ft
• b.6 ft 3 in
• c.6 ft 6 in✓
• d.7 ft

The minimum headroom of working space is 6 ft 6 in (or the height of the equipment if taller). The lesser heights do not satisfy the requirement, and 7 ft exceeds the minimum.2023 NEC §110.26(A)(3)

What is the line current of a 30 kVA, three-phase load supplied at 208 V?

• a.144 A
• b.100 A
• c.72 A
• d.83 A✓

For a three-phase load, I = VA ÷ (V × 1.732) = 30,000 ÷ (208 × 1.732) = 30,000 ÷ 360 = 83 A. Dividing by 208 alone or by 120 gives the incorrect single-phase-style results.

A complete bid price for an electrical project generally consists of which of the following?

• a.Material, labor, overhead, and profit✓
• b.Labor only
• c.Material only
• d.Permit fees only

A full bid adds up direct material, direct labor, overhead (indirect business costs), and profit. Leaving out any of these, such as bidding labor or material alone, would not cover the true cost of doing the work.

The NEC is updated on a three-year cycle. The 2023 NEC directly follows which prior edition?

• a.2017 NEC
• b.2020 NEC✓
• c.2014 NEC
• d.There is no prior edition

On the three-year cycle, the edition immediately before the 2023 NEC is the 2020 NEC. The 2017 and 2014 editions are earlier cycles, not the one directly preceding 2023.