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

Where must a PV system's disconnecting means be installed under Berkeley's checklist?

• a.At a readily accessible location✓
• b.Behind the modules in the array
• c.On the roof right next to the array
• d.Inside the attic near the hatch

The PV system disconnecting means must be installed at a readily accessible location. An attic is not readily accessible. A roof location would put a responder on the array. Behind the modules is not accessible.City of Berkeley 2022-code checklist (CEC 690.13)

How must interconnected power sources be grounded, according to Berkeley's 2022-code checklist?

• a.Through the module frames
• b.Per CEC Article 250✓
• c.By a floating connection at the inverter
• d.By a wire clipped to the roof vent

The checklist says interconnected sources shall be grounded in accordance with CEC 250. Module frames alone are not the grounding system. A floating connection provides no fault path. A roof vent is not a grounding electrode.City of Berkeley 2022-code checklist

What is the aggregate ESS limit for attached or detached garages under the 2022 CRC?

• a.80 kWh✓
• b.20 kWh
• c.40 kWh
• d.160 kWh

Garages and detached accessory structures may hold up to 80 kWh in aggregate. 20 kWh is the limit for one unit. 40 kWh is the limit for closets, basements and storage spaces. 160 kWh is double the garage limit.2022 CRC R328 (County of Lake excerpt)

Which impact protection for a garage ESS does the 2022 CRC give as an accepted option?

• a.A 48-inch Schedule 80 steel pipe in concrete✓
• b.A 2-inch PVC pipe set in loose gravel fill
• c.A 24-inch plastic wheel stop bolted down
• d.A painted yellow line on the garage floor

One accepted bollard is a minimum 48-inch length of 3-inch Schedule 80 steel pipe embedded in a concrete pier. A wheel stop does not protect a wall-mounted unit. PVC in gravel would not stop a vehicle. A painted line stops nothing.2022 CRC R328 (County of Lake excerpt)

Under 2022 CEC Article 706, how must an ESS nameplate be located?

• a.Inside the enclosure behind a door
• b.Plainly visible after installation✓
• c.On the utility meter
• d.In the owner's manual

Each ESS must have a nameplate plainly visible after installation. Behind a door it is not visible after installation. The utility meter is not the ESS. A manual alone is not a nameplate.County of Lake 2022-code excerpt (CEC 706.4)

In an AC-coupled PV and storage system, where do the PV and the batteries interact?

• a.On the DC side through one inverter with DC inputs for both
• b.On the AC side, at a central AC location✓
• c.Through the utility meter
• d.At the module terminals

An AC-coupled system brings the PV and ESS together on the AC side, with a PV breaker and an ESS breaker. A shared inverter with DC inputs describes a DC-coupled system. Module terminals are far upstream of any AC connection. The meter measures energy and is not where the systems interact.County of San Diego PDS 081S (2025 codes)

A city has passed the final building inspection for a PV system. What else is needed before it may operate in parallel with the grid?

• a.The utility's interconnection approval✓
• b.A signed letter from the HOA
• c.Nothing; the building permit covers it
• d.A CSLB certificate of completion

The building permit and the utility's interconnection approval are separate; the installer receives an interconnection permit from the utility. The city permit does not authorize connection to the utility's grid. CSLB does not issue a certificate of completion for operation. An HOA letter is not an interconnection requirement.DOE, Planning a Home Solar Electric System

A voltage dip lasts a fraction of a second. According to DOE, what does a standard small grid-tied inverter do?

• a.Reverses the power flow back into the PV array
• b.Rides through the disturbance and stays on✓
• c.Disconnects and waits for a manual reset on site
• d.Opens the AC disconnect permanently

DOE says the standard for small inverters is to ride through small disruptions and disconnect only if the disruption is large or long. Disconnecting for every brief dip would cause needless outages. Power flow cannot be reversed into the array. Inverters do not open the disconnect by themselves and lock out.DOE, Solar Integration: Inverters and Grid Services Basics

Where does the 2022 Energy Code's storage-ready rule call for space for system isolation equipment or a transfer switch?

• a.In the attic above the panelboard
• b.Within 25 feet of the nearest array
• c.Within 10 feet of the utility meter
• d.Within 3 feet of the main panelboard✓

Section 150.0(s) calls for space for a transfer switch or isolation equipment within 3 feet of the main panelboard. 10 feet from the meter is not the stated distance. An attic location is not required and would be hard to reach. The array location is irrelevant to the main panelboard rule.County of Lake 2022-code excerpt (Energy Code 150.0(s))

What is the status of the older NEM tariffs for new customers, according to the CPUC?

• a.They remain open to everyone until 2030
• b.They are available for systems under 10 kW
• c.They credit exports at the wholesale rate
• d.They are closed to new enrollments✓

The CPUC states the older NEM tariffs are closed to new enrollments, and new customers take the net billing tariff. There is no open window for new enrollments. System size does not reopen the closed tariffs. The older tariffs used retail rates, not wholesale.CPUC, Net Energy Metering and Net Billing

What lets a solar-plus-battery system run without the grid in an outage?

• a.A standard grid-tied inverter by itself
• b.A utility smart meter at the service entrance
• c.An advanced inverter built to run off-grid✓
• d.A larger array feeding the same inverter

DOE says solar-plus-battery systems rely on advanced inverters to operate without grid support, if designed to do so. A standard grid-tied inverter shuts down when the grid is lost. More modules do not change how the inverter reacts to the outage. A meter only measures energy.DOE, Solar Integration: Inverters and Grid Services Basics

The 2022 Energy Code's storage-ready option with backed-up capacity includes how many storage-supplied branch circuits?

• a.Eight, the kitchen and bath circuits
• b.Four, including a refrigerator circuit✓
• c.Two, the HVAC and the water heater
• d.One, the main lighting circuit

The option calls for four backed-up circuits that include the refrigerator, a lighting circuit near the primary egress and a sleeping-room receptacle. One circuit is fewer than required. HVAC and water heater are not the listed circuits. Eight circuits is double the requirement.County of Lake 2022-code excerpt (Energy Code 150.0(s))

For a backup installation, what does San Diego County want identified and available on site?

• a.The installer's general liability insurance policy
• b.The neighbor's meter number and street address
• c.Critical loads and load centers, with calculations✓
• d.The inverter's serial number and firmware

The checklist wants critical loads and load centers clearly identified, with load calculations available on site. A neighbor's meter number is irrelevant. A serial number does not show what the backup serves. Insurance paperwork does not describe the loads.County of San Diego PDS 081S (2025 codes)

In utility-controlled equipment such as a meter socket, which connections does the 2022 CEC permit?

• a.Connections made with a listed lug
• b.Connections that carry under 30 amps
• c.Connections the installer prefers
• d.Only ones the utility signs off on✓

In equipment under the utility's exclusive control, only connections the electric utility accepts are permitted. The installer does not decide inside utility equipment. Current level does not override the utility's control. A listed lug does not give permission.County of Lake 2022-code excerpt (CEC 705)

What must sealed storage cells be equipped with?

• a.Open drain tubes
• b.Pressure-release vents✓
• c.Water refill ports
• d.Gas-recombination catalysts

Sealed cells must have pressure-release vents so internal pressure cannot build up. Sealed cells are not refilled with water. Open drain tubes would defeat the seal. A catalyst does not substitute for a pressure-release vent.County of San Diego PDS 081S (2025 codes)

Where must a stand-alone system's battery cells be placed?

• a.In an unventilated closet
• b.On an open rack in the living area
• c.Inside a lockable enclosure or room✓
• d.Beside the inverter with unrestricted access

The checklist calls for cells inside a lockable enclosure or room, with ventilation suited to the battery technology. An open rack lets anyone reach live terminals. Unrestricted access defeats the lock requirement. An unventilated closet traps gases.County of San Diego PDS 081S (2025 codes)

At what voltage do Sandia's NEC notes say PV and battery systems present shock hazards?

• a.12 volts or higher
• b.240 volts or higher
• c.24 volts or higher
• d.50 volts or higher✓

Sandia says systems with voltages of 50 volts or higher present shock hazards. 12 volts is the level of an ordinary automotive battery, below the stated threshold. 24 volts is still below the stated threshold. 240 volts is far above the level where the hazard begins.Sandia, PV Power Systems and the NEC: Suggested Practices

About how much current can a single deep-cycle storage battery (6 volts, 220 ampere-hours) discharge into a short circuit, according to Sandia?

• a.About 8,000 amps✓
• b.About 1,000 amps
• c.About 220 amps
• d.About 800 amps

Sandia says one such battery can discharge about 8,000 amps into a short circuit. 220 is the ampere-hour rating, not a current. 40 amps is a small branch-circuit level. 100 amps understates the short-circuit capability by far.Sandia, PV Power Systems and the NEC: Suggested Practices

What does San Diego County's checklist require to keep stand-alone battery spaces safe from gas buildup?

• a.A fan that runs in summer months
• b.Ventilation suited to the battery technology✓
• c.A window in the wall, whatever the battery type
• d.None; the room has a working door and lock

The checklist calls for ventilation appropriate to the battery technology, inside a lockable enclosure or room. A door does not ventilate gases. A window cannot be counted on for every battery type. Seasonal fan use does not match gas production.County of San Diego PDS 081S (2025 codes)

How must all battery systems be treated under San Diego County's stand-alone rules?

• a.Stacked without a rack
• b.Placed in the driving path of the garage
• c.Left exposed so leaks are visible
• d.Protected from damage✓

All battery systems must be protected from physical damage. Exposure invites damage. The driving path is where vehicle strikes happen. Unracked stacking risks falls and damage.County of San Diego PDS 081S (2025 codes)

How does NREL say field battery life compares with manufacturers' literature?

• a.About ten times longer than the literature says
• b.About double, thanks to careful use and cooling
• c.About half, from heat and low charge✓
• d.The same as the literature says

NREL says field life is often about half of the literature figure, most likely due to overheating and long periods at low state of charge. Field life is not longer than the literature figure. Real-world conditions rarely match the literature exactly. Ten times longer is not plausible.NREL Best Practices for O&M of PV and ESS

Sandia compares 100 amps of short-circuit current in a large PV system to what?

• a.A 600-volt open-circuit condition✓
• b.A 12-volt car battery under a hood
• c.A 24-volt low-voltage thermostat circuit
• d.A 120-volt household lighting circuit

Sandia says 100 amps of short-circuit current can be as difficult to handle as an open-circuit voltage of 600 volts. A 12-volt battery is not comparable in hazard. A 120-volt circuit understates the comparison. A thermostat circuit is a very low-power circuit.Sandia, PV Power Systems and the NEC: Suggested Practices

A 12 kWh battery bank allows use of 80 percent of its rated capacity. How much energy is usable?

• a.9.6 kWh✓
• b.0.96 kWh
• c.15 kWh
• d.11.2 kWh

Usable energy is 12 x 0.80 = 9.6 kWh. 15 kWh divides by 0.80 instead of multiplying. 11.2 kWh subtracts 0.8 kWh rather than 20 percent. 0.96 kWh moves the decimal point one place.Stand-alone battery sizing (CSLB C-46 outline)

According to Poway's compliance list, what words open the label placed at service equipment?

• a.SOLAR PV SYSTEM IS EQUIPPED WITH RAPID SHUTDOWN✓
• b.SOLAR ARRAY SHUTS ITSELF OFF AT NIGHT
• c.ROOF POWER IS OFF WHEN THE MAIN SWITCH IS OFF
• d.SOLAR SYSTEM IS DISCONNECTED FROM THE UTILITY GRID

The list gives the words SOLAR PV SYSTEM IS EQUIPPED WITH RAPID SHUTDOWN, followed by the instruction to turn the switch to OFF. The array does not shut itself off at night through this system. Roof power is not simply off whenever the main switch is off; the label names rapid shutdown. This wording does not state that rapid shutdown is installed.City of Poway 2022-code list (CEC 690.56(C))

What colors does the Guidebook's label table give for the rapid shutdown label?

• a.White lettering on a blue background
• b.Red lettering on a white background
• c.Red background, white lettering✓
• d.Black lettering on a yellow background

The label table calls for a red background with white lettering. Black on yellow is not the stated scheme. Red on white reverses the colors. Blue is not the stated background.Solar Permitting Guidebook (OPR) label table

What must an alternate power source placard be made of under San Diego County's checklist?

• a.Paper in a clear plastic sleeve, zip-tied on
• b.A handwritten tag on laminated weatherproof card
• c.A printed vinyl sticker with adhesive backing
• d.Engraved metal or plastic in a contrasting color✓

The placard must be metal or plastic with engraved letters in a contrasting color. Paper in a sleeve fades and tears outdoors. A printed sticker is not engraved and is not durable enough. A handwritten tag is not permanent.County of San Diego PDS 081S (2025 codes)

What must the warning label required with a breaker positioned under a power control system or busbar rule tell people?

• a.The breaker may be moved whenever service needs room
• b.The overcurrent device must never be relocated✓
• c.A solar array is on the roof above this panel
• d.The main breaker is on the left side of the panel

San Diego County's checklist cites a warning not to relocate the overcurrent device at the power source output connection, so no one moves the breaker and defeats the busbar calculation. Moving the breaker for service is exactly what the warning forbids. A note that an array is on the roof describes the array, not the breaker restriction. The main breaker's side of the panel is a location note, not a warning against relocating.County of San Diego PDS 081S (2025 codes)

Besides being visible after installation, what must PV labels be?

• a.Removable for easy inspection by anyone
• b.Suited to its environment✓
• c.Printed in at least two languages
• d.Mounted on the inverter enclosure

Labels must be visible after installation and suitable for the environment where installed. Labels must stay put, not come off. Two languages are not required by this rule. Labels belong on raceways, boxes and equipment, not just the inverter.City of Berkeley 2022-code checklist (CEC 690.31)

When should polarity be verified during commissioning?

• a.Never; connectors prevent any reversal
• b.Once a year, after commissioning, at the annual visit
• c.At all combiners and inverter inputs, before switching on✓
• d.After the inverter is energized and running

Polarity is checked at every combiner, disconnect and inverter input before any switch is closed so reversed wiring cannot damage equipment. Checking after energizing risks damaging the inverter. An annual check alone is too late to protect equipment at startup. Connectors do not ensure correct conductor assignment.NREL Best Practices for O&M of PV and ESS

What does a rapid shutdown test at commissioning confirm?

• a.That the utility meter is sealed and read
• b.That modules produce full rated power at noon
• c.That shutdown makes devices respond✓
• d.That the main breaker trips on a bolted overload

The test initiates rapid shutdown and confirms the equipment responds as required. Rated power is a performance matter, not a shutdown test. Meter sealing is the utility's concern. Overload tripping is a breaker test, not a rapid shutdown test.Solar Permitting Guidebook (OPR) inspection checklist

At turnover, which items should the installer show the owner how to find and use?

• a.The module serial numbers printed on the roof
• b.The utility's pole-mounted transformer
• c.The shutdown switch and emergency disconnects✓
• d.The monitoring app login and password

Educating the client includes where the shutdown switch and emergency disconnects are and what the labels mean. The transformer belongs to the utility and is not for the owner to operate. A login alone does not teach safe shutdown. Serial numbers are paperwork and not safety controls.NREL Best Practices for O&M of PV and ESS

What governs the inverter's grid settings at commissioning?

• a.The customer's preference for self-consumption
• b.The racking manufacturer's installation instructions
• c.The module manufacturer's published data sheet
• d.The utility's interconnection approval requirements✓

Inverter settings follow the utility's interconnection approval under Rule 21. A module data sheet describes modules, not grid behavior. Racking instructions cover the mounting system. The customer cannot choose settings the utility requires.CPUC Rule 21 (Electric Rule 21 overview)

NREL recommends giving the homeowner what at turnover?

• a.A full set of the utility's current rate tariffs
• b.The installer's business tax records for the job
• c.A manual with contacts, indicators and procedures✓
• d.The roof structural calculations for the array

NREL recommends a manual with contact information and a description of operational indicators and procedures the homeowner can do. Tax records are not operating information. Structural calculations alone do not teach operation. Tariffs do not help the owner run the system.NREL Best Practices for O&M of PV and ESS

When is string operating current measured during commissioning?

• a.Once a year after the owner moves in
• b.Before any switch is closed at the combiner
• c.Once the inverter runs, per string✓
• d.While the array is covered by a tarp

Operating current can only be read with the array delivering power, so it is measured once the inverter is running. With no switch closed there is no operating current to read. A covered array produces no meaningful current. Waiting a year would miss installation faults.NREL Best Practices for O&M of PV and ESS

Which settings are configured at commissioning for a storage system?

• a.Roof pathway widths and ridge setback sizes
• b.Label font sizes, colors and wording rules
• c.Module tilt angles and tracker travel limits
• d.Backup reserve, self-consumption, export limits✓

Storage modes such as backup reserve, self-consumption and export limits are set at commissioning. Tilt is a mechanical matter set at installation. Pathway widths are layout decisions. Label sizes are code items, not inverter settings.NREL Best Practices for O&M of PV and ESS

What should the owner be told about a sudden drop in output in the monitoring portal?

• a.It means the portal is broken
• b.It deserves a service call✓
• c.It is normal seasonal variation
• d.It matters after a full year

Output declines slowly, so a sudden drop points to a problem worth a call. Seasonal change is gradual, not sudden. A drop in measured output is not assumed to be a portal error. Waiting a year leaves a fault running.NREL Best Practices for O&M of PV and ESS

If a listed power control system is used for the busbar calculation, how is its setting treated?

• a.As the main breaker's rating
• b.As the inverter's peak surge rating
• c.As unimportant; it can be changed freely
• d.As the design source current, and it is labeled✓

The PCS setting is considered the power-source output circuit current, so it is a design value and is labeled. An arbitrary change would defeat the busbar calculation. Surge rating is a different figure. The main breaker has its own rating.County of Lake 2022-code excerpt (CEC 705)

Which paperwork should the owner receive at turnover?

• a.The installer's payroll records for the crew
• b.Manuals, warranties, utility approval✓
• c.The inspector's personal field notes on the job
• d.The crew's individual training and safety logs

The owner needs the manuals, warranties, the interconnection approval and, for storage, the maintenance provider's contact label. Payroll records belong to the contractor's business. Training logs are internal. An inspector's notes are not owner documents.NREL Best Practices for O&M of PV and ESS

Where should integral collector-storage (batch) systems be installed, according to DOE?

• a.Indoors in the attic
• b.Anywhere; the tank is insulated
• c.In climates with regular hard freezes
• d.Only in mild-freeze climates✓

The stored water sits outdoors in the collector, so DOE says ICS systems belong only where freezes are mild. Insulation does not protect outdoor pipes in severe cold. Hard freezes are exactly where the outdoor pipes would freeze. An attic location would not let the collector heat the water.DOE Energy Saver, Solar Water Heaters

What does the solar energy factor of a solar water heater measure?

• a.Hours of sun per year at the site
• b.Collector area per gallon of storage
• c.Energy delivered divided by energy put in✓
• d.The share of the load supplied by the sun

DOE defines the solar energy factor as the energy delivered by the system divided by the electrical or gas energy put into it. That describes the solar fraction, which is a different rating. Collector area per gallon is a sizing ratio. Sun hours describe the climate, not the system's rating.DOE Energy Saver, Estimating the Cost and Energy Efficiency of a Solar Water Heater

Why are double-wall heat exchangers less efficient than single-wall ones?

• a.They are required to run at lower flow rates
• b.They use noticeably less copper tubing
• c.Heat must cross two surfaces, not one✓
• d.They hold more antifreeze in the jacket

DOE explains that heat must pass through two surfaces rather than one, which lowers efficiency. Copper quantity does not explain the loss. Flow rate is not the reason given. Antifreeze volume is not the reason given.DOE Energy Saver, Solar Water Heaters

A solar water heating system's daily load is 34,120 Btu. About how many kilowatt-hours is that, at 3,412 Btu per kWh?

• a.About 100 kWh
• b.About 1 kWh
• c.About 10 kWh✓
• d.About 3.4 kWh

34,120 divided by 3,412 is 10 kWh. 100 kWh moves the decimal point the wrong way. 1 kWh divides by 34,120 instead of 3,412. 3.4 kWh divides 34,120 by 10,000.EIA, Energy conversions (Btu per kWh)

What is a drawback of air as a solar heat-transfer fluid, according to DOE?

• a.It is toxic in small amounts
• b.It corrodes copper tubing quickly
• c.It freezes solid at 20 degrees F
• d.Its heat capacity is very low✓

DOE notes air will not freeze or boil and is non-corrosive, but has a very low heat capacity. Air does not freeze in a collector loop. Air is not toxic. Air is non-corrosive.DOE Energy Saver, Solar Water Heaters

How does a pool cover affect the collector area needed for solar pool heating?

• a.It requires glazed collectors instead
• b.It usually decreases the required area✓
• c.It increases the required collector area
• d.It has no effect on the area needed

DOE says you can usually decrease the required collector area by using a pool cover. A cover reduces heat loss, so it lowers the need for area. A cover does change heat loss, so it does have an effect. A cover does not change the collector type.DOE Energy Saver, Solar Swimming Pool Heaters

A pool slopes uniformly from 3 feet deep at one end to 9 feet deep at the other. What average depth is used to find its volume?

• a.3 feet
• b.9 feet
• c.6 feet✓
• d.4.5 feet

For a uniform slope the average is (3 + 9) / 2 = 6 feet. 3 feet is only the shallow end. 9 feet is only the deep end. 4.5 feet halves the deep end alone.NIST Handbook 44 Appendix C (volume units)

Which pool collector costs more but works better in cold weather and can also heat domestic water, per DOE?

• a.An unglazed rubber collector on the roof
• b.A glazed copper collector✓
• c.A black plastic drum set on the roof ridge
• d.A bare black plastic hose loop on the roof

DOE describes glazed collectors of copper tubing on an aluminum plate under iron-tempered glass as costlier but better in cold weather. Unglazed rubber collectors are the low-cost warm-weather type. A hose loop is not a DOE collector type. A drum is not a pool collector.DOE Energy Saver, Solar Swimming Pool Heaters

Replacing a conventional pool heater with solar may call for what, according to DOE?

• a.A smaller filter, with the same pump
• b.No pump at all; solar heating is passive
• c.A larger pump, or a separate smaller one✓
• d.A second sand filter on the return line

DOE says solar may need a pump larger than the current one, or a separate smaller pump to move water through the collectors. A smaller filter does not move water to the roof. Collectors need pumped flow. A second filter does not address pumping.DOE Energy Saver, Solar Swimming Pool Heaters

When can unglazed collectors serve an indoor pool in a cold climate?

• a.If antifreeze circulates through the pool
• b.If the collectors face north at a steep tilt
• c.If it is designed to drain back to the pool✓
• d.If the collectors are painted white on top

DOE says unglazed collectors can serve indoor pools in cold climates if the system drains back to the pool when idle. White paint would reduce absorption and does not stop freezing. A north orientation reduces heat and does not prevent freezing. Antifreeze in pool water is not a design option.DOE Energy Saver, Solar Swimming Pool Heaters

DOE reports a typical installed cost of $2,500 to $4,000 for a solar pool heater. What payback does it give?

• a.8 to 12 years
• b.1 to 7 years✓
• c.15 to 20 years
• d.Under 3 months

DOE gives a payback of between 1 and 7 years for a solar pool heating system. 15 to 20 years is far longer than DOE reports. 8 to 12 years is longer than DOE reports. Under 3 months is far shorter than DOE reports.DOE Energy Saver, Solar Swimming Pool Heaters

On a clear day all strings show low current together. Where should the diagnosis start?

• a.The grounding electrode system at the service
• b.Irradiance, soiling or shade over the array✓
• c.A single failed bypass diode in one module
• d.One string's fuse and its fuse holder

A shortfall shared by all strings points to a cause common to the array: sunlight, dirt or shade. One failed diode affects one module or string. One blown fuse affects one string. The grounding electrode does not change current output.NREL Best Practices for O&M of PV and ESS