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

Before choosing solar, what does DOE advise a homeowner to consider first?

• a.A larger inverter than the array needs
• b.Whether a neighbor has installed solar
• c.Low-cost efficiency measures✓
• d.Moving to a higher electric rate tier

DOE advises knowing your usage and considering low-cost, easy-to-implement efficiency measures before choosing solar, since every kWh saved is one you need not generate. A neighbor's decision says nothing about the home's own load. An oversized inverter adds cost without lowering the load. A higher rate tier raises the bill and is not a planning step.DOE, Planning a Home Solar Electric System

Which roof direction does CSLB's Solar Smart guide tell buyers to look for?

• a.A flat roof under tall trees
• b.A roof facing north under trees
• c.A roof facing south, SE or SW✓
• d.A roof facing due east

The guide tells buyers to make sure the roof faces the southern sky, including southwestern and southeastern directions, and is not shaded. A north-facing plane gets the least sun in California. East-only facing misses the afternoon sun and is not the guide's advice. A shaded roof under trees defeats the purpose of the advice.CSLB Solar Smart

A 9.0 kW DC array feeds a 7.5 kW AC inverter. What is the DC-to-AC ratio?

• a.1.5
• b.1.2✓
• c.16.5
• d.0.83

The ratio is the DC array rating divided by the inverter's AC rating: 9.0 divided by 7.5 is 1.2, a common choice that may clip a little output at midday. 0.83 inverts the fraction by dividing the AC rating by the DC rating. 1.5 does not come from these two ratings. 16.5 adds the two ratings instead of dividing them.NREL PVWatts Version 5 Manual

A 500-watt module has a power temperature coefficient of -0.4 percent per degree C. Its cells run 20 degrees C above the 25 degrees C test temperature. About how much power does it produce, other conditions equal?

• a.About 460 W✓
• b.About 492 W
• c.About 540 W
• d.About 400 W

The loss is 20 degrees times 0.4 percent, or 8 percent, and 500 W less 8 percent is 460 W. Heat lowers power, so the result cannot rise above the rating. 492 W counts only 0.4 percent once instead of per degree. 400 W treats the coefficient as 1 percent per degree, which is too large.NREL PVWatts Version 5 Manual (temperature coefficient)

Modules are rated 45.0 V open-circuit, the lowest expected temperature is -3 degrees C (correction factor 1.12), and the dwelling's system voltage limit is 600 V. What is the greatest number of modules in one series string?

• a.13
• b.11✓
• c.10
• d.12

Each module counts as 45.0 x 1.12 = 50.4 V in the cold, and 11 modules give 554.4 V, under 600 V. 13 comes from dividing 600 by the nameplate voltage and skipping the cold correction. 12 modules give 604.8 V once corrected, which is over the limit. 10 modules are allowed but are not the greatest number that fits.Solar Permitting Guidebook (OPR) standard plan

How do monocrystalline and polycrystalline modules compare, according to DOE?

• a.Monocrystalline is cheaper and less efficient
• b.Mono is more efficient; poly is cheaper to make✓
• c.Polycrystalline is more efficient and costs more
• d.Both have identical cost and efficiency

DOE says monocrystalline panels are more efficient because electrons move more freely, while polycrystalline cells are less expensive to manufacture. This reverses the two cell types. The two types differ in both cost and efficiency. Monocrystalline is the costlier, more efficient type.DOE, Solar Photovoltaic Cell Basics

On a roof plan drawn at 1/4 inch = 1 foot, a walkway between two array blocks measures 1/2 inch. Does it meet a 36-inch firefighter pathway requirement?

• a.No; it scales to 24 inches✓
• b.Yes; it scales to 36 inches
• c.Yes; it scales to 48 inches
• d.No; it scales to 12 inches

One-half inch divided by 0.25 is 2 feet, or 24 inches, which is narrower than the 36-inch pathway. 36 inches would need a 3/4-inch measurement at this scale. 48 inches would need a 1-inch measurement at this scale. 12 inches would need a 1/4-inch measurement at this scale.2022 CRC R324.6 (City of Berkeley checklist)

According to the Solar Permitting Guidebook, where must the location of the rapid shutdown initiation device be shown?

• a.On the module data sheet
• b.On the utility bill summary
• c.On the structural plan sheet
• d.On the site plan drawing✓

The Guidebook says the initiation device's location shall be shown on the site plan drawing. The structural plan covers framing and attachments, not equipment locations. A module data sheet describes the product and has no information about this installation. A utility bill summary has nothing to do with equipment placement on the property.Solar Permitting Guidebook (OPR)

What does a single-line diagram show most directly?

• a.The distance from each module to the ridge
• b.The framing members under each rail run
• c.The street-side fire pathway to the ridge
• d.Electrical path from array to service✓

A single-line diagram shows the electrical path with one stroke per circuit, along with ratings, so you can check strings, breakers and the interconnection. Distances on the roof belong to the roof or site plan. Framing members belong to the structural plan. Fire pathways are drawn on the site and roof plans.City of Berkeley 2022-code checklist

Which information must a permit electrical plan show for both the DC and the AC side of the system?

• a.Setback distances to property lines
• b.Roof pitch and roofing material type
• c.Rafter sizes and spacing in the roof
• d.Conductor sizes and insulation ratings✓

Berkeley's checklist asks the electrical plan to give conductor sizes and insulation ratings on both sides, along with raceways, the service size and labels. Rafter information belongs on the structural plan. Property-line distances belong on the site plan. Roof pitch and roofing type are site and structural information, not electrical.City of Berkeley 2022-code checklist

Which three core drawings do building departments typically ask for in a solar permit set?

• a.A site plan, a structural plan and an electrical plan✓
• b.A floor plan, a plumbing plan and a landscape irrigation plan
• c.A grading plan, a drainage plan and a street lighting plan
• d.A roofing plan, a color plan and a sales plan

Berkeley's checklist is typical: a site plan, a structural plan and an electrical plan with a single-line diagram. Floor, plumbing and landscape plans do not describe the array, its attachment or its wiring. Grading, drainage and lighting plans belong to site civil work, not the solar permit set. A color plan and a sales plan are not permit drawings.City of Berkeley 2022-code checklist

Which drawing shows the building footprint with distances to property lines, the array location and the fire access pathways?

• a.The site plan✓
• b.The electrical single-line diagram
• c.The structural plan
• d.The label schedule

The site plan shows the footprint, distances to property lines, the array, equipment and disconnect locations and the fire pathways. The structural plan shows framing and attachment details. The single-line diagram shows the electrical path, not the property layout. The label schedule lists markings, not locations of pathways.City of Berkeley 2022-code checklist

What should you find first on a plan sheet before measuring any distance from it?

• a.The north arrow on the site plan
• b.The sheet number in the corner
• c.The sheet's drawing scale✓
• d.The revision date in the title block

Every measured distance depends on the scale, so it is the first thing to find. A north arrow gives direction, not size. The sheet number identifies the page, not the proportion. The revision date says nothing about size.CSLB C-46 outline (interpret plans)

On a single-line diagram, a back-fed breaker in the main panel represents what kind of connection?

• a.A load-side connection✓
• b.A ground-mount tie
• c.A supply-side connection
• d.A utility-owned tap

A back-fed breaker on the panel's bus connects the PV output on the load side of the service disconnecting means. A supply-side connection joins ahead of the service disconnect. A utility tap is made by the utility. A ground-mount tie is not a type of interconnection.City of Berkeley 2022-code checklist (CEC 705)

A three-person crew works 2 days of 8 hours each, plus 4 more crew hours for commissioning. At $90 per labor hour, what is the labor cost?

• a.$4,320
• b.$5,400
• c.$4,680✓
• d.$1,800

3 x 2 x 8 = 48 hours, plus 4 gives 52 hours, and 52 x $90 is $4,680. $4,320 prices only the 48 installation hours and leaves out commissioning. $1,800 prices 20 hours, one worker's share. $5,400 charges the 4 commissioning hours to each of the three workers.Estimating (labor), CSLB C-46 outline

A system's net cost after incentives is $21,000 and it saves the owner $1,750 a year. What is the simple payback?

• a.12 years✓
• b.8 years
• c.14 years
• d.10 years

Simple payback is net cost divided by annual savings: 21,000 divided by 1,750 is 12 years. 8 years would need savings of $2,625 a year. 10 years would need savings of $2,100 a year. 14 years would need savings of $1,500 a year.CSLB Solar Smart (breakeven point)

A rail run is 24 feet long and attachments are spaced every 48 inches, with one at each end. How many attachments does one rail run need?

• a.5
• b.6
• c.7✓
• d.8

24 feet is 288 inches; 288 divided by 48 is 6 spans, and 6 spans need 7 attachments counting both ends. 6 counts spans and forgets the attachment at the far end. 5 divides 24 by 5, which is not the spacing. 8 adds an extra attachment that no span needs.Estimating (takeoff), CSLB C-46 outline

A contractor's direct costs for a job are $15,000, and the contractor adds 20 percent of cost for overhead and profit. What is the contract price?

• a.$18,000✓
• b.$20,000
• c.$15,300
• d.$18,750

A 20 percent addition on cost is 15,000 x 1.20 = $18,000. $18,750 treats 20 percent as a margin on price, dividing by 0.80. $15,300 adds 2 percent, not 20. $20,000 adds a flat $5,000 with no basis.Estimating (markup), CSLB C-46 outline

How many business days does the standard home improvement contract notice give a buyer to cancel under section 7159?

• a.Three business days✓
• b.Seven business days
• c.Ten business days
• d.One business day

The standard notice reads that the buyer has the right to cancel within three business days. One day is shorter than the notice states. Seven days is longer than the standard notice. Ten days is longer than the standard notice.California Business and Professions Code 7159

The CSLB solar energy system disclosure document under section 7169 applies to residential systems of what size?

• a.At least 1 kW up to 5 MW AC✓
• b.A residential system under 1 kW AC
• c.Systems of 10 kW AC or less in size
• d.Systems that include battery storage units

Section 7169 covers residential systems of at least 1 kW and no more than 5 MW AC. Systems under 1 kW fall below the threshold. 10 kW AC is the expedited permitting size, not the disclosure scope. The rule is not limited to systems with batteries.California Business and Professions Code 7169

Which document does CSLB's Solar Smart guide tell buyers to get signed by the contractor, subcontractors and suppliers?

• a.A blank warranty form
• b.Mechanics lien release forms✓
• c.The contractor's tax return
• d.A utility letter approving payment

CSLB tells buyers to get mechanics lien release forms signed by the contractor, subcontractor and materials suppliers. A blank warranty form protects nothing and should never be signed blank. A tax return is not a payment protection document. A utility letter does not release liens.CSLB Solar Smart