CSLB C-46 Solar (Trade Exam) — All Questions

A homeowner's highest bill is in August, but the bills vary widely by month. What is the best starting figure for sizing a PV system?

• a.The average bill in dollars
• b.The kWh from the most recent bill
• c.The August kWh multiplied by twelve
• d.The total kWh over twelve months✓

DOE advises reviewing electricity bills to find annual needs in kWh, checking every month because use changes through the year. Multiplying the peak month by twelve oversizes the system, and dollars do not measure energy.DOE, Planning a Home Solar Electric System

In California, which fixed-array orientation generally gives the highest annual energy output?

• a.Facing true south at about latitude tilt✓
• b.Facing true north at a low tilt
• c.Lying flat with no tilt at all
• d.Facing due east at a steep tilt

DOE states that for the highest annual output in the northern hemisphere, modules point due south and tilt at an angle equal to the local latitude. East-facing and flat arrays can work but produce less over a year.DOE, Solar Photovoltaic System Design Basics

A neighbor's hedge, planted after a solar collector was installed, now shades 15 percent of the collector at 11 a.m. local standard time. Under the Solar Shade Control Act, what is the status of that hedge?

• a.It is allowed because hedges are exempt
• b.It violates the Act only after 3 p.m.
• c.It is allowed because shade is under 25 percent
• d.It violates the Act's 10 percent limit✓

The Act bars trees or shrubs placed after installation from shading more than 10 percent of the collector absorption area between 10 a.m. and 2 p.m. local standard time. Fifteen percent at 11 a.m. exceeds that limit; the Act does not exempt hedges.California Public Resources Code 25982 (Solar Shade Control Act)

A homeowner's rooftop collector is designed to produce twice the building's electricity demand. How does the Solar Shade Control Act apply to it?

• a.It is protected if it faces true south
• b.It is protected only for the first 10 years
• c.It is outside the Act's "solar collector" definition✓
• d.It is protected only against shade from buildings

Public Resources Code 25981 excludes from the definition a solar collector designed and intended to offset more than the building's electricity demand. Orientation and age do not change that definition.California Public Resources Code 25981

An HOA requires a solar water heating system to use a different collector color that adds $400 to a $6,000 system and changes nothing else. Under Civil Code 714, is that a reasonable restriction?

• a.Yes; the added cost is under 10 percent✓
• b.No; HOAs may not regulate solar heaters
• c.No; any added cost makes it unreasonable
• d.Yes, but only if approved within 90 days

For solar water and pool heating, a restriction is significant if it adds more than 10 percent of the system cost (capped at $1,000) or cuts efficiency more than 10 percent. $400 is under 10 percent of $6,000, so the restriction can be reasonable.California Civil Code 714

A homeowner association denies a solar application by phone and never sends anything in writing. What does Civil Code 714 require of an association's decision?

• a.The approval or denial must be in writing✓
• b.Only approvals must be in writing
• c.A phone call is enough if it is recorded
• d.The decision must be mailed within 90 days

Civil Code 714 requires an association's approval or denial of a solar application to be in writing, and an application not denied in writing within 45 days is deemed approved.California Civil Code 714

A city's building official finds, with substantial evidence, that a proposed solar system could have a specific, adverse impact on public health and safety. What may the city then require?

• a.A larger system to offset the impact
• b.An application for a use permit✓
• c.Approval from the neighbors
• d.A design review for appearance

Government Code 65850.5 lets the city require a use permit only after such a finding based on substantial evidence; aesthetic design review is exactly the kind of barrier the statute discourages.California Government Code 65850.5

For a small residential rooftop solar system eligible for expedited review, how many inspections does state law require?

• a.As many as the building official wants
• b.One for framing and one for electrical
• c.Only one inspection✓
• d.Three: rough, final and utility

Government Code 65850.5 states that for an eligible small residential rooftop system only one inspection shall be required, which may be consolidated. A separate fire inspection is allowed only in limited circumstances.California Government Code 65850.5

Modules rated 40.2 V open-circuit go where the lowest expected temperature is −4 °C. Using the Guidebook's correction factor, what is the corrected voltage of a 13-module string?

• a.About 596 V
• b.About 585 V✓
• c.About 523 V
• d.About 467 V

The Guidebook uses a factor of 1.12 when the lowest temperature is at or above −5 °C: 40.2 × 13 × 1.12 ≈ 585 V. Without the factor, 40.2 × 13 = 522.6 V, which understates the cold-morning voltage.Solar Permitting Guidebook (OPR) standard plan

On a very hot afternoon, how does a crystalline PV module's output change compared with a cool morning at the same sunlight?

• a.Voltage rises and power rises
• b.Nothing changes; only sunlight matters
• c.Voltage drops noticeably and power falls✓
• d.Current drops sharply while voltage holds steady

DOE explains that higher temperatures cause a slight increase in current but a much larger decrease in voltage, so power falls. Cells work best at low temperatures.DOE, Solar Photovoltaic Performance and Efficiency Basics

What default total system loss does NREL's PVWatts Version 5 apply, and how is it combined?

• a.5 percent, applied to AC output only
• b.14 percent, from losses multiplied together✓
• c.14 percent, the simple sum of losses
• d.25 percent, the simple sum of losses

PVWatts uses a default total loss of 14 percent and notes that the total is not the sum of the individual losses; it is found by multiplying the reductions for soiling, shading, mismatch, wiring and the rest.NREL PVWatts Version 5 Manual

A customer is signing a power purchase agreement (PPA). What does the CSLB's Solar Smart guide say the customer pays for?

• a.The equipment, in fixed monthly lease payments
• b.Nothing, since the utility pays the company
• c.The system in full, at installation
• d.The power produced, at a set kWh price✓

The CSLB describes a PPA as allowing a company to install and own a system on the home while the customer buys the electricity it produces at a pre-established price per kWh, often with an escalator clause.CSLB Solar Smart

Which information must appear on the CSLB solar energy system disclosure document required by B&P 7169?

• a.The utility's future rate forecast
• b.The names of the crew members
• c.Total cost and payments, including financing✓
• d.The installer's home address

Section 7169 requires the disclosure document to show the total cost and payments for the system, including financing costs, along with complaint information and the consumer's cancellation right.California Business and Professions Code 7169

A solar contract is priced at $7,500. What is the most the contractor may collect as a down payment?

• a.$1,500
• b.$1,000
• c.$75
• d.$750✓

B&P 7159 caps the down payment at $1,000 or 10 percent of the contract price, whichever is less. Ten percent of $7,500 is $750, which is less than $1,000.California Business and Professions Code 7159

An array covers 28 percent of a home's plan-view roof area, and the home has no sprinklers. What setback is required at a horizontal ridge?

• a.18 inches on both sides✓
• b.No setback below 33 percent
• c.36 inches on both sides
• d.18 inches on one side only

For arrays covering not more than 33 percent of the plan-view roof area, the 2022 CRC requires at least 18 inches of clear setback on both sides of a horizontal ridge. The setback is reduced, not removed, below 33 percent.2022 CRC R324.6.2 (City of Berkeley checklist)

A sprinklered home (NFPA 13D) will have an array covering 70 percent of its plan-view roof area. What ridge setback applies?

• a.36 inches on both sides✓
• b.12 inches on both sides
• c.18 inches on both sides
• d.None, because it is sprinklered

With an automatic sprinkler system, the alternative setback is 18 inches for arrays covering up to 66 percent of plan-view roof area and 36 inches above that. At 70 percent, 36 inches applies.2022 CRC R324.6.2.1 (City of Poway list)

Which roof is exempt from the residential PV pathway requirements?

• a.A 9:12 roof on a detached garage used as a studio
• b.A 1.5:12 low-slope roof on a house✓
• c.A 4:12 roof on a two-story house
• d.A 6:12 roof with a small array

The pathway rules do not apply to roofs with slopes of 2:12 or less, or to non-habitable structures. A studio is habitable, and steeper roofs on houses are covered regardless of array size.2022 CRC R324.6 (City of Poway list)

Under which standard must a rooftop-mounted PV panel system be tested and listed for its fire classification?

• a.UL 2703✓
• b.UL 1973
• c.UL 9540
• d.UL 1741

The 2022 CRC requires rooftop-mounted PV panel systems installed on or above the roof covering to be tested, listed and identified with a fire classification in accordance with UL 2703. UL 1741 covers inverters and UL 9540 covers energy storage systems.2022 CRC R902.4 (County of Lake excerpt)

What added dead load does NREL say a typical attached (not ballasted) rooftop PV system adds?

• a.About 15 pounds per square foot
• b.About 25 pounds per square foot
• c.Less than 3 pounds per square foot✓
• d.3 to 8 pounds per square foot

NREL reports that an attached system adds less than 3 pounds per square foot of collector area, while a ballasted system adds 3 to 8 pounds per square foot depending on tilt and wind loading.NREL Best Practices for O&M of PV and ESS

Why does NREL prefer through-bolting to clamps for PV rack hardware?

• a.Through-bolts eliminate the need for flashing
• b.Clamps can release in a storm✓
• c.Through-bolts need no corrosion protection
• d.Clamps are not allowed by any code

NREL notes clamps may have the specified strength in the proper orientation, but relative movement, rotation or vibration of rack parts in a storm can cause them to release; through-bolting is preferred. Flashing is still required.NREL Best Practices for O&M of PV and ESS

What must be true of every roof penetration made for a PV installation, per San Diego County's checklist?

• a.It must be inspected by the roofer
• b.It must be at least 24 inches from a rafter
• c.It must be secure and weather-tight✓
• d.It must be sealed with silicone only

San Diego County's checklist requires all roof penetrations to be secure and weather-tight. The method follows the approved plan and manufacturer details, not a single sealant type.County of San Diego PDS 081S (2025 codes)

What does a single-axis tracker on a ground-mounted array typically do?

• a.Points directly at the sun all day in both axes
• b.Tilts the array toward north in winter
• c.Rotates the array only at night
• d.Follows the sun from east to west✓

DOE explains that one-axis trackers typically track the sun from east to west, while two-axis trackers keep modules pointed directly at the sun throughout the day. Trackers add cost and maintenance.DOE, Solar Photovoltaic System Design Basics

Which standard lists photovoltaic shingles used as the roof covering?

• a.UL 9540
• b.UL 1741
• c.UL 2703
• d.UL 7103✓

The 2022 CRC requires PV shingles to be listed and labeled in accordance with UL 7103 and limits them to roof slopes of 2:12 or greater. UL 2703 applies to rack-mounted PV systems.2022 CRC R905.16 (County of Lake excerpt)

At inspection, which statement about exposed array conductors must be true?

• a.They may rest loose on the roof surface
• b.They must run through the attic in PVC
• c.They are secured, supported and protected✓
• d.They must be painted to match the roof

The Guidebook's inspection list requires array exposed conductors to be properly secured, supported and routed to prevent physical damage. DC circuits inside a building must be in metal raceway, MC cable or metal enclosures, not PVC.Solar Permitting Guidebook (OPR) inspection checklist

What does NREL say a ballasted rooftop rack requires beyond the general ASCE 7 requirements?

• a.Advanced wind-loading evaluations✓
• b.A ground-mounted backup array
• c.A fire classification of Class C only
• d.No wind review, since ballast holds it down

NREL states that to use a ballasted rack, advanced wind-loading evaluations have to be performed above the general requirements of ASCE 7, and wind loading usually decides whether ballast is feasible.NREL Best Practices for O&M of PV and ESS

Which fastener does NREL describe as more likely to pull out of PV racking over time?

• a.Stainless steel bolts
• b.Listed lag screws into rafters
• c.Self-tapping screws✓
• d.Through-bolts with nuts

NREL notes that self-tapping screws are more likely to pull out and weaken over time from corrosion, and that through-bolting is preferred to clamps in rack hardware.NREL Best Practices for O&M of PV and ESS

According to NREL, roofing contractors frequently guarantee their workmanship for how long?

• a.30 to 40 years
• b.Exactly 1 year
• c.Only until the first rain
• d.Between 5 and 10 years✓

NREL notes that roofing contractors often guarantee their work for between 5 and 10 years for workmanship, which a PV installation can affect if penetrations are not made to the roofing and racking details.NREL Best Practices for O&M of PV and ESS

How often does NREL's sample service schedule call for inspecting roof penetrations for degrading sealant?

• a.Only when a leak is reported
• b.Never, once flashed
• c.Once a year✓
• d.Once every 10 years

NREL's sample service schedule includes inspecting roof penetrations once a year to ensure sealant is applied properly and not degrading.NREL Best Practices for O&M of PV and ESS

A building-integrated PV system hides electrical hazards from view. What does the 2022 California Fire Code require?

• a.No markings, since BIPV is part of the roof
• b.Reflective markings of the hazard areas, visible from grade✓
• c.A fence around the building
• d.Removal of the BIPV at night

The 2022 CFC requires markings identifying hazardous areas to avoid where BIPV creates hidden electrical hazards, and the markings must be reflective and visible from grade.County of Lake 2022-code excerpt (CFC 1205.2.3)

Which smoke ventilation option between array sections does the 2022 California Fire Code allow on larger buildings?

• a.No pathway if modules are Class A
• b.A pathway not less than 18 inches wide
• c.A pathway not less than 8 feet wide✓
• d.A single roof hatch anywhere on the roof

The 2022 CFC's smoke ventilation options between array sections include a pathway at least 8 feet wide, or a 4-foot pathway bordering 4-by-8-foot venting cutouts every 20 feet on alternating sides.County of Lake 2022-code excerpt (CFC 1205.3.3)

Why does NREL say ground-mounted arrays usually need more cleaning than rooftop arrays?

• a.They face north
• b.They sit closer to dust and pollen✓
• c.They are cleaned only by rain
• d.They have no glass

NREL notes that cleaning requirements increase for ground-mounted arrays because they are closer to the source of airborne dirt and pollen.NREL Best Practices for O&M of PV and ESS

What is the basic job of a PV inverter?

• a.Raise the modules' open-circuit voltage
• b.Convert DC from the modules to AC for the grid✓
• c.Convert AC from the grid to DC for the modules
• d.Store energy for use at night

DOE describes the inverter as a device that converts direct current, which a solar panel generates, to alternating current, which the grid uses. Storage is the job of batteries.DOE, Solar Integration: Inverters and Grid Services Basics

A string operates at 360 V and 9.5 A. What power is it producing?

• a.3,420 W✓
• b.369.5 W
• c.37.9 W
• d.34,200 W

DOE notes that electrical power is the product of current and voltage: 360 × 9.5 = 3,420 W, or 3.42 kW. Dividing or adding the values gives meaningless results.DOE, Solar Photovoltaic Performance and Efficiency Basics

Why does the PV current calculation include a 1.25 factor on module short-circuit current?

• a.The inverter adds 25 percent to the current
• b.Sunlight can exceed the 1,000 W/m² test level✓
• c.It converts DC current to AC current
• d.Modules lose 25 percent of current each year

Sandia's guide explains that normal daily irradiance may exceed the 1,000 W/m² standard test condition, and these higher currents are covered by the 1.25 adjustment. A second 1.25 factor applies to conductor ampacity, for 1.56 combined.Sandia, PV Power Systems and the NEC: Suggested Practices

A string's modules have a rated short-circuit current of 12.0 A. Using the combined PV factor, what is the minimum conductor ampacity before other corrections?

• a.24.0 A
• b.18.7 A✓
• c.12.0 A
• d.15.0 A

The two 1.25 factors combine to 1.56: 12.0 × 1.56 ≈ 18.7 A. Using only one factor gives 15.0 A, which is the maximum circuit current, not the conductor ampacity target.Sandia, PV Power Systems and the NEC: Suggested Practices

DC PV conductors will run inside a house from the attic to a garage inverter. Which wiring method is acceptable?

• a.USE-2 cable stapled to framing
• b.Nonmetallic sheathed cable
• c.Metal raceway✓
• d.PVC conduit

Where PV DC circuits run inside a building, the 2022 CEC requires metal raceways, MC metal-clad cable meeting 250.118(10), or metal enclosures. Nonmetallic methods do not meet the rule.City of Berkeley 2022-code checklist (CEC 690.31)

A string inverter is mounted in a closet, and its separate DC disconnect is in the hallway 6 feet away, visible from the inverter. Is the location acceptable for an equipment disconnect?

• a.Yes; it is in sight and within 10 feet✓
• b.No; it must be at the service panel
• c.Yes, but only if it is also locked
• d.No; it must be inside the inverter

The 2022 CEC permits an equipment disconnect within the equipment, or within sight and within 10 feet of it. Six feet and in sight meets the rule.City of Berkeley 2022-code checklist (CEC 690.15)

A building has a PV system with rapid shutdown. What must the permanent label at each service equipment location include?

• a.The installer's contract price
• b.The serial number of each module
• c.The daily energy production
• d.A simple building and roof diagram✓

Poway's list states that the label must include a simple diagram of the building with a roof, along with the required wording about turning the rapid shutdown switch off to reduce shock hazard in the array.City of Poway 2022-code list (CEC 690.56(C))

A 200-amp busbar has a 150-amp main breaker, and the PV breaker is at the opposite end. What is the largest inverter output current that fits the 120 percent rule?

• a.40 A
• b.72 A✓
• c.90 A
• d.50 A

120 percent of 200 A is 240 A; minus the 150 A main leaves 90 A for 125 percent of the inverter current. 90 ÷ 1.25 = 72 A. Stopping at 90 A forgets that the inverter current is multiplied by 1.25.Solar Permitting Guidebook (OPR) standard plan

Where must the PV point of connection be made in a panel, according to the Guidebook's inspection list?

• a.On a shared branch breaker with other loads
• b.At any neutral bar screw
• c.At a dedicated breaker or disconnect✓
• d.Directly to the main lugs with no breaker

The Guidebook's inspection list requires the point of connection to be at a dedicated breaker or disconnect, and a back-fed breaker used for interconnection must not be marked "line and load."Solar Permitting Guidebook (OPR) inspection checklist

Where in a panelboard does San Diego County's checklist require the PV connection to be positioned?

• a.In the middle of the busbar
• b.Directly next to the main breaker
• c.Opposite the feeder or main✓
• d.On the neutral bar

The checklist requires the PV connection in the panelboard to be positioned at the opposite (load) end from the input feeder or main circuit location, consistent with the 120 percent rule.County of San Diego PDS 081S (2025 codes)

A DC conduit makes a 90-degree bend in an attic. Where must a PV warning marking be placed relative to the bend?

• a.Within 1 foot of the bend✓
• b.Nowhere, if the bend is hidden
• c.Within 5 feet of the bend
• d.Only at the conduit's ends

San Diego County's checklist requires markings every 10 feet and within 1 foot of turns or bends, and within 1 foot above and below penetrations of roofs, ceilings, walls or barriers.County of San Diego PDS 081S (2025 codes)

What must be marked at an interactive PV system's point of interconnection?

• a.Rated AC current and nominal AC voltage✓
• b.The array's open-circuit voltage only
• c.The date of the final inspection
• d.The installer's license number

CEC 690.54 requires the interconnection point to be marked at the disconnecting means as a power source, with the rated AC output current and nominal operating AC voltage.City of Berkeley 2022-code checklist (CEC 690.54)

How must an alternate power source placard be fastened to the service disconnect in San Diego County?

• a.With rivets or screws✓
• b.With epoxy adhesive
• c.With double-sided tape
• d.With plastic cable ties

The checklist requires the metal or plastic engraved placard to be attached with pop-rivets, machine screws or other approved fasteners, and states that epoxy is not an acceptable method.County of San Diego PDS 081S (2025 codes)

What is the maximum energy rating of a single residential ESS unit under the 2022 CRC?

• a.40 kWh
• b.20 kWh✓
• c.80 kWh
• d.10 kWh

The 2022 CRC limits individual ESS units to 20 kWh. The 40 and 80 kWh figures are aggregate limits for particular locations such as utility spaces, garages, exterior walls and outdoor ground installations.County of Lake 2022-code excerpt (CRC R328)

Two residential ESS units will hang on the same garage wall. What minimum spacing applies unless fire testing documents less?

• a.3 feet✓
• b.10 feet
• c.18 inches
• d.6 inches

The 2022 CRC requires individual ESS units to be separated by at least 3 feet unless smaller separations are documented as adequate by large-scale fire testing.County of Lake 2022-code excerpt (CRC R328.3.1)

An ESS is installed in an attached garage where a smoke alarm cannot be installed based on its listing. What detection is required?

• a.A sprinkler head above the ESS
• b.No detection in garages
• c.A carbon monoxide alarm only
• d.An interconnected, listed heat detector✓

The 2022 CRC requires a listed heat detector, interconnected to the smoke alarms, in dwelling unit and attached garage locations where smoke alarms cannot be installed based on their listing.County of Lake 2022-code excerpt (CRC R328.7)

Which is a requirement for an ESS disconnecting means under the 2022 CEC?

• a.It must be installed on the roof
• b.It must disconnect only the grounded conductor
• c.It must be hidden from the homeowner
• d.It must be lockable open✓

CEC 706.15 requires the ESS disconnect to be readily accessible, located within sight of the ESS (or field-marked where that is impractical), and lockable open in accordance with 110.25.County of Lake 2022-code excerpt (CEC 706.15)

A customer applied for interconnection with a large California utility in 2025. Which tariff generally applies?

• a.NEM 1.0 at full retail export credit
• b.The net billing tariff✓
• c.No tariff; exports are prohibited
• d.NEM 2.0, since it is still open

The CPUC states that since April 15, 2023, customers applying for interconnection have taken service on the net billing tariff; the NEM tariffs are closed to new enrollments.CPUC, Net Energy Metering and Net Billing

During commissioning, which test finds DC faults that the monitoring system cannot detect?

• a.Manual Voc, current and I-V tests✓
• b.Checking the inverter's paint finish
• c.Measuring the roof pitch again
• d.Reading the utility's monthly bill

NREL describes manual electrical testing — open-circuit voltage, operating current, or field I-V curve tracing — as the way to detect DC faults that monitoring does not see.NREL Best Practices for O&M of PV and ESS