CSLB C-46 Solar (Trade Exam) — All Questions
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70 questions
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)
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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
What can a grid-forming inverter do that a conventional grid-following inverter cannot?
- a.Operate without any DC source
- b.Ignore the utility's interconnection rules
- c.Restart a grid that went down✓
- d.Raise module efficiency above 40 percent
DOE explains that grid-forming inverters can start up a grid if it goes down, a process called black start, while grid-following inverters need a signal from the grid to match.DOE, Solar Integration: Inverters and Grid Services Basics
Which grid service does DOE say modern inverters can provide?
- a.Converting AC back into sunlight
- b.Raising the utility's retail rate
- c.Providing and absorbing reactive power✓
- d.Storing energy without a battery
DOE notes that modern inverters can both provide and absorb reactive power to help grids balance that resource, one of several grid services advanced inverters can supply.DOE, Solar Integration: Inverters and Grid Services Basics
Which item must appear on an energy storage system's nameplate under the 2022 CEC?
- a.The homeowner's name
- b.Available fault current at the output terminals✓
- c.The date of the next utility bill
- d.The installer's license number
CEC 706.4 requires a nameplate plainly visible after installation, marked with items including the manufacturer, rated frequency, rating in kW or kVA, available fault current at the output terminals, maximum currents and voltages, and utility-interactive capability.County of Lake 2022-code excerpt (CEC 706.4)
Article 706 of the 2022 CEC applies to energy storage systems above what capacity?
- a.More than 20 kWh
- b.More than 1 kWh✓
- c.More than 80 kWh
- d.More than 100 Wh
Article 706 applies to all energy storage systems having a capacity greater than 3.6 MJ (1 kWh). The 20 kWh and 80 kWh figures are residential unit and location limits in the CRC.County of Lake 2022-code excerpt (CEC 706.1)
A new single-family home uses the busbar option to meet the 2022 Energy Code's storage-ready rule. What minimum main panelboard busbar rating applies?
- a.400 amps
- b.100 amps
- c.225 amps✓
- d.150 amps
The 2022 Energy Code's ESS-ready provisions include a main panelboard with a minimum busbar rating of 225 amps, along with other storage-ready measures such as backed-up circuits and space for a transfer switch.County of Lake 2022-code excerpt (Energy Code 150.0(s))
An ESS technology can release toxic gas during normal charging and discharging. Where does the 2022 CRC prohibit it?
- a.Nowhere, if a detector is installed
- b.Within Group R-3 or R-4 occupancies✓
- c.Only on rooftops
- d.Only in commercial warehouses
The 2022 CRC states that ESS with the potential to release toxic or highly toxic gas during charging, discharging and normal use shall not be installed within Group R-3 or R-4 occupancies.County of Lake 2022-code excerpt (CRC R328.12)
Besides converting DC to AC, what does DOE say a household inverter often does?
- a.Monitors the system and communicates data✓
- b.Replaces the need for a disconnect
- c.Stores excess energy for the night
- d.Measures the roof's structural load
DOE notes that a household inverter can monitor the system and provide a portal for communication with computer networks, in addition to converting solar energy into AC power.DOE, Solar Integration: Inverters and Grid Services Basics
Which requirement applies to a power source disconnecting means under 2022 CEC 705.20?
- a.It must be operable only with a tool
- b.It must be hidden inside the inverter
- c.It must plainly show open or closed✓
- d.It must open only the grounded conductor
CEC 705.20 requires the power source disconnect to plainly indicate whether it is in the open (off) or closed (on) position, to open all ungrounded conductors simultaneously, and to be readily accessible and externally operable.County of Lake 2022-code excerpt (CEC 705.20)
Residential ESS installations that exceed the CRC's individual or aggregate energy ratings must follow which code section?
- a.California Fire Code Section 1207✓
- b.California Plumbing Code Chapter 5
- c.The utility's Rule 21 tariff
- d.CEC Article 690 only
The 2022 CRC states that ESS installations exceeding the permitted individual or aggregate ratings shall be installed in accordance with Section 1207 of the California Fire Code.County of Lake 2022-code excerpt (CRC R328 and R328.10)
What does the Guidebook's inspection list say about access around inverters, disconnects and panelboards?
- a.Working space is needed only for the utility meter
- b.Working space is needed around the modules
- c.No working space is needed for listed equipment
- d.Working space for operation and maintenance✓
The inspection list calls for access and working space for operation and maintenance of equipment such as inverters, disconnects and panelboards. Listing does not remove the working space requirement. Modules are not the equipment this working-space item is about. The requirement covers the PV equipment named, not just the meter.Solar Permitting Guidebook (OPR) inspection checklist
What does San Diego County's checklist require for systems with microinverters or integrated inverters?
- a.A rooftop AC disconnect✓
- b.A DC disconnect at the meter
- c.No disconnect; there is no DC wiring
- d.A disconnect at the utility pole
The checklist requires microinverter and integrated systems to have a rooftop AC disconnect. The system still has AC wiring that must be isolable. A DC disconnect at the meter does not serve an AC array. A pole disconnect is the utility's, not the installer's.County of San Diego PDS 081S (2025 codes)
How does the Guidebook's inspection list want AC and DC disconnects and overcurrent protection to be arranged?
- a.They are scattered around the building for safety
- b.They are hidden behind the modules
- c.They are listed, grouped and identified✓
- d.They are unlisted but labeled
Listed AC and DC disconnects and overcurrent protection are grouped and identified. Scattering them makes shutdown harder. Unlisted equipment does not satisfy the list. Hiding them defeats the purpose of identification.Solar Permitting Guidebook (OPR) inspection checklist
What rating must exposed PV wiring outdoors carry under San Diego County's checklist?
- a.Wet-location listed, sun resistant✓
- b.Rated for a dry location, not wet ones
- c.Insulation rated for 60 degrees C
- d.Rated for use inside a dry building
All exposed wiring must be listed for wet location and sunlight resistant. Outdoor wiring sees rain, so dry-only is not enough. Indoor-rated wiring is not built for sun and weather. A temperature rating alone does not address moisture and sunlight.County of San Diego PDS 081S (2025 codes)
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