CSLB C-46 Solar (Trade Exam) — All Questions
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38 questions
What median annual degradation rate did NREL's review of nearly 2,000 measured PV rates find?
- a.0.5 percent per year✓
- b.0.05 percent per year
- c.2 percent per year
- d.5 percent per year
NREL's review of nearly 2,000 reported degradation rates found a median of 0.5 percent per year and a mean of 0.8 percent per year, with 78 percent of rates below 1 percent per year.NREL, Photovoltaic Degradation Rates — An Analytical Review
What does NREL say measured PV performance must be compared against to be meaningful?
- a.The installer's sales brochure
- b.A neighbor's electric bill
- c.The module's shipping weight
- d.Expected-performance modeling✓
NREL states that measured performance is meaningful only when compared to a model of expected performance, and lists wire losses, module rating, mismatch, shading, soiling and degradation as factors affecting that model.NREL Best Practices for O&M of PV and ESS
A pyranometer used to calculate a site's performance ratio is covered in dust. What effect does NREL describe?
- a.It has no effect on any calculation
- b.It exaggerates the performance ratio✓
- c.It lowers the array's actual output
- d.It raises the modules' voltage
NREL notes that dirt on a pyranometer will exaggerate the performance ratio, because the sensor under-reports sunlight. The array's actual output is not changed by a dirty sensor.NREL Best Practices for O&M of PV and ESS
What maintenance does NREL recommend for PV modules when cleaning is needed?
- a.Follow the maker's cleaning recommendations✓
- b.Pressure-wash at close range
- c.Use a strong solvent to cut grime
- d.Use abrasive pads to remove film
NREL says to follow the PV module manufacturer's recommendations for any array cleaning, and to clean with plain demineralized water and a mild detergent the manufacturer recommends.NREL Best Practices for O&M of PV and ESS
NREL describes wire management failures on PV arrays. Which cause is named?
- a.Modules that face true south
- b.Plastic ties that break or pinch✓
- c.Conductors that are too large
- d.Inverters that are listed to UL 1741
NREL notes that wire management depends on plastic ties and grommets that can break or pinch wires, and on exposure to sunlight, wind, ice and chewing rodents.NREL Best Practices for O&M of PV and ESS
What does NREL say is a common cause of a ground fault on a PV array?
- a.A wire rubbing a module frame✓
- b.A module facing the wrong direction
- c.A clean irradiance sensor
- d.Too few modules in a string
NREL describes corrective maintenance as finding and repairing ground faults, such as a wire scraping against a module frame, and arc faults caused by a broken wire or loose connection.NREL Best Practices for O&M of PV and ESS
Over a PV array's 25-year life, how many inverter replacements does DOE expect?
- a.One every two years
- b.Exactly five
- c.None
- d.At least one✓
DOE states that inverters are expected to need replacement at least once in the 25-year lifetime of a PV array, which belongs in long-term cost planning.DOE, Solar Photovoltaic System Design Basics
A solar water heater's pump runs during the day but not at night, and hot water production is normal. What does this show?
- a.The collector sensor is shorted
- b.The tank sensor is open
- c.The starting capacitor has failed
- d.The delta-T control is working✓
DOE explains that the delta-T controller starts the pump when the collector is hotter than the tank and stops it otherwise, so daytime-only operation is normal. A pump running at night points to sensor faults.DOE Energy Saver, Solar Water Heating System Maintenance and Repair
A temperature sensor on a solar collector outlet reads far too low. What common problem does DOE point to?
- a.The collector glazing is too clean
- b.The pool cover is missing
- c.The glycol has turned into ethylene glycol
- d.The sensor fell off its surface✓
DOE says a common problem is temperature sensors simply falling off the surface they are meant to measure, and recommends fastening them with a lug or stainless steel clamp.DOE Energy Saver, Solar Water Heating System Maintenance and Repair
What does DOE recommend to remove sediment from a solar storage tank?
- a.Add more glycol to the tank
- b.Flush the tank periodically✓
- c.Raise the collector tilt
- d.Replace the tank every year
DOE recommends flushing storage tanks periodically to remove sediment, and replacing the sacrificial anode in steel tanks at the supplier's recommended interval.DOE Energy Saver, Solar Water Heating System Maintenance and Repair
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About how often can regular maintenance on a simple solar water heating system be scheduled, according to DOE?
- a.Every month without exception
- b.Every week
- c.Never; they need no maintenance
- d.Every 3 to 5 years✓
DOE says regular maintenance on simple systems can be as infrequent as every 3 to 5 years, preferably by a solar contractor, and that systems with electrical components usually need a replacement part or two after 10 years.DOE Energy Saver, Solar Water Heaters
A commercial building's 100 kWh lithium-ion ESS is replaced with a new model. How does the 2022 California Fire Code treat the replacement?
- a.As exempt from the fire code
- b.As routine maintenance
- c.As a new ESS installation✓
- d.As a repair needing no permit
The 2022 CFC states that replacements of ESS shall be considered new ESS installations and must meet the section's provisions for new ESS; repairs with non-identical parts are treated as retrofits. These general provisions cover ESS above the 20 kWh lithium-ion threshold outside dwellings; home batteries follow the Fire Code's residential section.County of Lake 2022-code excerpt (CFC 1207.3.8)
What record-keeping does the 2022 CEC require for an energy storage system?
- a.Only a photo of the nameplate
- b.A written maintenance and repair record✓
- c.A monthly utility bill copy
- d.None, if the system is under warranty
CEC 706.7 requires ESS to be maintained in proper and safe condition and requires a written record of system maintenance, including repairs and replacements.County of Lake 2022-code excerpt (CEC 706.7)
An inverter's heat sink is caked with dust. What does NREL's sample annual service schedule include for this?
- a.Clean the heat sinks per the maker✓
- b.Nothing; dust does not affect inverters
- c.Paint the heat sink black to shed heat
- d.Remove the heat sink to improve airflow
NREL's sample schedule includes cleaning dust from inverter heat sinks and cleaning or changing air filters per the manufacturer's warranty requirements, once a year or more often in dusty conditions.NREL Best Practices for O&M of PV and ESS
A solar water heater in a dusty rural area delivers less heat each summer. What simple cause does DOE point to?
- a.Sunlight is weaker in rural areas
- b.Dusty or soiled collectors perform poorly✓
- c.The storage tank is too well insulated
- d.Glycol makes collectors too hot
DOE notes that dusty or soiled collectors perform poorly and that periodic cleaning may be needed where rain does not rinse them, such as near plowing dust or birds.DOE Energy Saver, Solar Water Heating System Maintenance and Repair
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
According to NREL, what do cell-level hot spots generally do to module performance?
- a.They do not significantly affect it✓
- b.They always trip the ground-fault detector
- c.They raise the open-circuit voltage
- d.They cut the string's output in half
NREL says cell-level hot spots generally will not significantly affect module performance, although a hot connection is a fire risk to correct. A single hot cell does not halve a string's output. A hot cell is not a ground fault. Heat lowers voltage rather than raising it.NREL Best Practices for O&M of PV and ESS
A system's model predicts 820 kWh for May, but the meter shows 700 kWh. About how large is the shortfall?
- a.About 15 percent✓
- b.About 17 percent
- c.About 8 percent
- d.About 120 percent
The shortfall is (820 - 700) divided by 820, or about 14.6 percent. 8 percent understates the gap. 120 is the number of kWh, not a percentage. 17 percent divides by 700, the wrong base.NREL Best Practices for O&M of PV and ESS
Which annual tests does NREL's sample service schedule include for a PV array?
- a.Utility meter calibration at the service
- b.String-level Voc and DC operating current✓
- c.Module serial number audits by the crew
- d.Roof framing moisture content readings
The sample schedule includes annual string-level open-circuit voltage and DC operating current tests. Framing moisture is a building matter. Serial audits do not test performance. Meter calibration is the utility's job.NREL Best Practices for O&M of PV and ESS
On a hot afternoon every string reads low in voltage together. What is the likely cause?
- a.A loose neutral
- b.High cell temperature✓
- c.A blown string fuse
- d.A single failed bypass diode
Higher temperature causes a much larger decrease in voltage, and it affects every string alike. A failed diode affects one module or string. A blown fuse affects one string's current. A loose neutral is an AC problem.DOE, Solar Photovoltaic Performance and Efficiency Basics
What does DOE say to check about valves on a solar water heating system?
- a.That the valves are lubricated weekly
- b.That the valves are closed for the winter
- c.That the valves are removed in summer
- d.That valves are in their proper positions✓
DOE's inspection list says to check that all valves are in the proper operating position. Closed valves would stop circulation. Removing valves is not a maintenance step. A weekly lubrication schedule is not DOE's advice.DOE Energy Saver, Solar Water Heating System Maintenance and Repair
On a solar water heater, where should an inspector look for fluid leaks?
- a.At the roof ridge
- b.At the collector glass cover
- c.At the storage tank lid or cap
- d.At every pipe connection✓
DOE says to look for fluid leaks at pipe connections. The glass is not where fluid joins. The tank lid is not a plumbing joint. The ridge has no pipe connections.DOE Energy Saver, Solar Water Heating System Maintenance and Repair
What does DOE say to look for on pipes, ducts and wiring?
- a.Excess lubricant on the fittings
- b.Extra supports under each pipe
- c.Insulation damage or degradation✓
- d.Fresh paint on the pipe covers
DOE says to look for damage or degradation of insulation covering pipes, ducts and wiring. Paint is not a performance concern. Lubricant has no role on insulation. More supports are not part of the check.DOE Energy Saver, Solar Water Heating System Maintenance and Repair
What does DOE say to check about the hardware that attaches collectors to their supports?
- a.That the bolts are painted
- b.That the bolts are loosened for expansion
- c.That the nuts are replaced yearly
- d.That all fasteners are tight✓
DOE says to check all nuts and bolts attaching collectors to support structures for tightness. Paint does not secure a collector. Yearly replacement of every nut is not DOE's advice. Loosened bolts would let the collector shift.DOE Energy Saver, Solar Water Heating System Maintenance and Repair
What does DOE say to look for in collector glazing?
- a.Tree sap on the aluminum frame
- b.Fingerprints from the installer's gloves
- c.Dew on the underside of the glass
- d.Cracks, and whether the seals are good✓
DOE says to look for cracks in the glazing and check that the seals are in good condition. Fingerprints do not affect performance. Sap on the frame is not the glazing inspection. Dew alone does not say whether the seals are good.DOE Energy Saver, Solar Water Heating System Maintenance and Repair
According to DOE, systems with electrical components usually need what after about 10 years?
- a.A complete replacement of the tank
- b.Nothing at all
- c.A replacement part or two✓
- d.A new roof
DOE says systems with electrical components usually require a replacement part or two after 10 years. DOE does not say the whole tank must be replaced. Electrical parts wear and eventually need replacing. A new roof is unrelated.DOE Energy Saver, Solar Water Heaters
Why may collector glazing need cleaning in dry climates, according to DOE?
- a.Dry air makes the glass brittle
- b.No natural rainwater rinse✓
- c.Sunlight bakes dirt onto the frame
- d.Dust is magnetic and clings to glass
DOE says glazing may need cleaning in dry climates where rainwater does not provide a natural rinse. Dry air does not make glass brittle. Dust is not magnetic. Frame baking is not the stated reason.DOE Energy Saver, Solar Water Heaters
After an inverter is replaced, what must still work with the equipment that remains?
- a.The previous monitoring portal login
- b.The former AC disconnect label
- c.The rapid shutdown function✓
- d.The old inverter's warranty
Equipment performing rapid shutdown must be listed for it, so the function must still work after the replacement. The warranty belongs to the removed unit and is not an operating function. A portal login is a convenience, not a safety function. A label does not perform a shutdown function.City of Berkeley 2022-code checklist (CEC 690.12)
What must a repair or alteration to an existing PV system not do?
- a.Require a new utility meter at the service
- b.Make existing equipment lose its listing✓
- c.Take more than a day of labor on the roof
- d.Change the module color from the original
Berkeley's checklist says alterations or additions must not cause existing equipment or components to lose their listings. Color has nothing to do with listing. Duration is not part of the rule. A new meter is not part of the rule.City of Berkeley 2022-code checklist
Under the Fire Code's general ESS provisions, how is a repair that uses non-identical parts treated?
- a.As a retrofit of the ESS equipment✓
- b.As a brand-new ESS installation
- c.As routine maintenance of the unit
- d.As a cosmetic change to the unit
The Fire Code treats repairs with other than identical parts as retrofitting. Identical-part repairs are the routine maintenance. Replacement of the whole ESS is what counts as a new installation. Non-identical parts change the equipment, so it is not cosmetic.2022 CFC 1207 (County of Lake excerpt)
Who may repair an energy storage system under the Fire Code's general provisions?
- a.Qualified personnel only✓
- b.A helper under verbal instruction
- c.The homeowner with the manual
- d.The utility's lineworkers
The Fire Code says repairs of ESS shall only be done by qualified personnel. Owner repairs are not authorized by the manual. Verbal instruction does not make someone qualified. The rule is about qualification, not employer, so lineworkers are not the only ones.2022 CFC 1207 (County of Lake excerpt)
What must be left with the owner of a residential energy storage system?
- a.The utility's current rate schedule and all of its tariff sheets
- b.The crew's signed time sheets and daily job logs for the week
- c.A copy of the roofing contractor's workmanship warranty
- d.The manufacturer's installation and operation instructions✓
The code calls for a copy of the manufacturer's instructions and a label with the contact information of qualified service providers. Rate schedules are not part of the ESS documents. The roofing warranty is unrelated. Time sheets are internal business records.2022 CRC R328 (County of Lake excerpt)
When damaged module mounts are replaced, what governs how they are attached?
- a.Only the manufacturer's specifications✓
- b.The installer's usual practice on similar roofs
- c.Whatever fastener happens to be on the truck
- d.The roofer's preference
Module attachments must be in accordance with the manufacturer's specifications. A fastener on hand may not meet the specification. Habit is not a specification. The roofer's preference does not set structural attachment.City of Berkeley 2022-code checklist
A repair requires re-terminating a lug. What torque should be used?
- a.As tight as the wrench will allow it
- b.The manufacturer's recommended torque✓
- c.Snug by hand, then a quarter turn more
- d.Whatever value suits copper wire
Pressure terminals must be tightened to the manufacturer's recommended torque. Hand tight can leave a loose, heating connection. Over-tightening can damage the lug or conductor. The conductor material does not remove the torque specification.Solar Permitting Guidebook (OPR) inspection checklist
Berkeley's checklist requires PV equipment, wiring and interconnections to be installed by whom?
- a.The homeowner, using the manual
- b.A helper assigned to the crew
- c.The electric utility's own crew
- d.A qualified person per NFPA 70E✓
The checklist calls for installation by a qualified person trained per NFPA 70E 2018, which also applies when repairing or replacing. A helper without training is not qualified. The homeowner is not assumed qualified. The utility does not do the installer's work.City of Berkeley 2022-code checklist
When replacement modules are installed, what does the Guidebook's inspection list want to match the permit plan?
- a.The installer's shirt color and logo
- b.Module model, quantity and location✓
- c.The truck's license plate number
- d.The module color and finish
The inspection list checks that modules match the plan in model, quantity and location. Color is not what the list checks. Crew clothing is not an inspection item. The truck plate is not an inspection item.Solar Permitting Guidebook (OPR) inspection checklist
What must DC breakers used in a PV system be?
- a.Rated for use in a household refrigerator circuit
- b.Any ordinary AC breaker of the right size
- c.Unlisted when under 20 amps
- d.Listed and rated for use with PV systems✓
San Diego County's checklist says DC breakers shall be listed and rated for PV use, which also governs replacements. An AC-only breaker may not interrupt a DC arc. A refrigerator rating has no bearing on DC PV use. Small size does not remove the listing requirement.County of San Diego PDS 081S (2025 codes)
After an ESS repair, what must the unit carry for the owner's benefit?
- a.No label on the unit
- b.A sticker saying the unit cannot be serviced by anyone
- c.A label with the crew's home addresses and phone numbers
- d.A label with qualified service provider contacts✓
The code calls for a label containing the contact information for the qualified maintenance and service providers. Home addresses are not the required information. The unit can be serviced by qualified providers. The code does call for a label.2022 CRC R328 (County of Lake excerpt)