Lighting and Electrical Systems Flashcards
7 cards from real Certified Energy Auditor Certification practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Lighting and Electrical Systems flashcards as text
Which lighting source type has the highest luminous efficacy available in commercial products as of current standards?
Answer: LED
Commercial LED luminaires routinely achieve 150–200+ lm/W system efficacy, surpassing all other available commercial lamp technologies.
A facility operates at 480V three-phase. A voltage imbalance test shows Phase A = 478V, Phase B = 462V, Phase C = 482V. What is the approximate percent voltage imbalance?
Answer: 2.6%
Average = (478+462+482)/3 = 474V; max deviation = 474−462 = 12V; imbalance = 12/474 × 100 ≈ 2.5%, closest to 2.6%.
What is the purpose of a 'lighting power allowance' in ASHRAE 90.1's Building Area Method?
Answer: To set the maximum allowable LPD for an entire building based on its primary use type
The Building Area Method assigns a single maximum W/ft² allowance to the whole building based on its primary classification (e.g., office, retail, warehouse).
An auditor identifies induction motors running at 60% load as a major reactive power source. Which device placed near the motors would most efficiently correct the power factor locally?
Answer: Power factor correction capacitors
Capacitors installed at or near motor terminals supply reactive power locally, reducing reactive current in the upstream distribution system and improving facility power factor.
What is the significance of the 'Useful Life' rating (L70) for LED luminaires in an energy audit?
Answer: The hours at which lumen output has depreciated to 70% of initial output
L70 defines the operating hours at which a LED luminaire's light output has declined to 70% of its initial lumens, the industry standard threshold for end of useful life.
Which type of photosensor control wiring is most susceptible to false triggering from electrical noise in industrial facilities?
Answer: 0-10V analog
0-10V analog signals operate at low voltage levels and are vulnerable to EMI-induced voltage fluctuations that can falsely adjust dimming levels in electrically noisy environments.
During an electrical audit, an auditor finds that a facility pays for 500 kVAR of reactive power monthly. Installing power factor correction equipment brings the power factor from 0.72 to 0.95. What is the primary financial benefit beyond avoiding reactive power charges?
Answer: Reduced current draw, lowering conductor I²R losses and potentially reducing demand charges
Improving power factor reduces line current for the same real power, which decreases I²R resistive losses in conductors and may lower the peak kW demand measured by the utility.