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These 10 free CSLT questions are organized by exam domain, so you can see how each part of the Certified Senior Lighting Technician blueprint is tested. Reveal the answer and explanation under each question.
Two proposed 4000 K LED lamps deliver the same lumens. Both have Ra 88, but their R9 values are 22 and 72. A retailer wants more faithful rendering of deep-red fabrics without changing the nominal white-light appearance. Which choice best addresses that requirement?
Correct answer: A - Use the R9 72 lamp; Ra does not include the saturated-red test sample.
On a 120 V lighting circuit, a driver replacement raises measured true power factor from 0.70 to 0.95. A power analyzer shows unchanged real input watts, and annual operating hours remain the same. The proposal nevertheless claims lower kWh consumption solely from the higher power factor. Which assessment is supported?
Correct answer: A - Input current decreases, but energy use in kWh does not.
Compare two one-year plans for 120 same-age fluorescent lamps. Replacement lamps cost $6 each. Spot relamping requires an expected 60 visits, each using one lamp, 0.5 technician-hour at $60/hour, and $20 in access costs. Group relamping during a shutdown replaces all 120 lamps, uses 12 technician-hours at the same rate, and incurs $300 in access costs, with no further replacements expected that year. Both plans maintain required lighting, and no other costs differ. Which plan costs less over the year?
Correct answer: B - Group relamping, by $1,620.
With no daylight contribution, a clean lighting system originally provided 600 lux at a workplane. Its current lamp lumen depreciation factor is 0.80 and its luminaire dirt depreciation factor is 0.70. All other factors are unchanged. Cleaning will restore the dirt factor to 1.00 without replacing the lamps. The required maintained illuminance is 520 lux. What should the technician expect after cleaning?
Correct answer: A - 480 lux; cleaning alone will not meet the requirement.
Which replacement driver can operate an LED module that requires a fixed 700 mA, operates between 36 and 42 V, and has a maximum input power of 29.4 W? All four candidates meet the luminaire manufacturer's input-voltage, control, mounting, and environmental requirements; their output ratings are listed below.
Correct answer: C - 700 mA constant current; 30-48 V; 35 W maximum
A certified single-ended Type B LED conversion kit specifies line on one pin and neutral on the other pin at the powered end. The host luminaire is deenergized, its ballast has been removed, and its existing lampholders are shunted. The kit permits specified replacement lampholders and requires conversion labels. Which installation follows the kit’s circuit and labeling requirements?
Correct answer: D - Fit the specified nonshunted powered-end holder, wire its pins separately as directed, and apply the conversion labels.
A corridor’s annual 90-minute battery test completes without interruption, and initial illuminance passes. At 90 minutes, floor-level measurements are: average 0.78 fc, minimum 0.04 fc, maximum 1.20 fc, and maximum-to-minimum ratio 30:1. The end-of-test acceptance criteria are an average of at least 0.60 fc, a minimum of at least 0.06 fc, and a ratio no greater than 40:1. How should the result be recorded?
Correct answer: D - Fail: the minimum illuminance is below the end-of-test limit.
After tall opaque partitions are installed in an office, an automatic-on/automatic-off PIR sensor switches the lights off while people work at desks behind the partitions. Walking into the open aisle turns them back on. The specified 15-minute vacancy delay is correctly set. Which adjustment corrects the cause rather than masking it?
Correct answer: B - Reposition or add sensing to cover the occupied desks.
A qualified technician is preparing to replace an LED module in a luminaire with an integral emergency battery driver. The normal branch circuit is locked and tagged open, and absence of voltage has been verified at the AC input. The battery remains connected. Approved temporary egress lighting is in place. Before touching the module leads, the technician must:
Correct answer: C - Control battery and stored energy, then verify the module leads are deenergized.
An HPS parking-area luminaire reaches full output, goes dark, cools, and restarts repeatedly. Recorded supply voltage remains within rating. During deenergized servicing, its lamp is exchanged with the same lamp model from a normally operating luminaire with identical control gear. The cycling follows the original lamp; the replacement operates steadily. This pattern points to:
Correct answer: D - An aging HPS lamp whose arc can no longer be sustained.
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