CSLB C-46 Solar (Trade Exam) — All 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)

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)