CSLB C-46 Solar (Trade Exam) — All Questions
15 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