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67 Cards in this Set
- Front
- Back
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What is the term that describes the total amount of color corrected light emitted from a lamp?
What unit is it expressed in? |
Luminice Flux
Lumens |
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What is the term that describes the amount of light emitted from a source in a particular direction?
What unit is it expressed in? |
Luminice Intensity
Candela |
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What is the term that describes the amount of light that falls upon a surface?
What unit is it expressed in? |
Illuminance
footcandles |
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The amount of electrical energy required by a lamp is expressed in what units?
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Watts
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Would you choose a lamp with higher LPW or lower LPW and why?
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Higher
Better Efficiency |
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Out of the following lamps, which have the best Color Rendering Index: Sunlight, Fluorescent, Incandescent, Low Pressure Sodium?
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Sunlight
Incandescent |
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A customer would like to light a room in a warm, cozy light. Which of the following color termperature lamps would you recommend: 2700K, 6500K, 5500K?
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2700K
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A customer would like to light a room that already has some daylighting and would like a lamp with a color termperature similar to daylight. Which color termperature would you recommend: 2700K, 6500K, 5500K?
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2700K
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True or False: An object must be specular to produce reflected glare.
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False
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What is the difference between a diffuse and a speculare surface?
Give an example of each |
diffuse spreads light
specular reflects light in one direction Diffuse- projector screen Specular- mirror |
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When I look at a lamp or luminaire, what term expresses the amount of light that I see?
Where could I find that information for a given luminaire or lamp? |
cd
cd plot or ies chart |
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What is the diameter of a T8 lamp?
What is it's shape? |
8 means "8/8" so d = 1"
Tube |
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What does the MR in an MR16 lamp stand for?
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Multi-fasceted Reflector
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You have a lamp that is marked with the part number 39T5/835.
What is the color rendering index of the lamp? Coler Termperature? Wattage? Shape? Diameter? |
CRI = 80
Color Temp. = 3500 Wattage = 39 Shape = tube Diameter = 5/8" |
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Describe how you would determine the reflectance of a wall using an illuminance meter.
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Measure the light coming off the wall and divide by the amount of light hitting the wall.
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Since light is power, why don't we measure the total light output by a lamp in Watts? (What is the difference between watts and lumens?)
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Lumens are color corrected for our eyes while watts are not
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What does a ballast do?
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Limits current, increases voltage, raises frequency
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Modern electronic ballasts operate at a much higher frequency than older, electromagnetic ballasts. Name three significant advantages to operating at a higher frequency.
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Less noise, doesn't flicker, saves energy
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Where can you find the allowable Watt/ft^2 for a given space?
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ASHRAE 90.1
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What is the minimum illuminance level for a stairwell?
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5
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You are desining lighting for an industrial task that requires very fine detail and the contrast is low. The suggested illuminance level is 1500fc. What stratedgy would you use to provide that illuminance?
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Spot lighting or task lighting
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Name two significant advantages for using daylight to light a space.
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Free
Higher Quality |
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Name two significant challenges for using daylight to light a space.
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Unpredictable
Glare |
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What is a ballast factor and why is it important?
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Ballast factor is a measure of the actual lumen output for a specific lamp-ballast system relative to the rated lumen output measured with a reference ballast.
The ballast factor is needed to determine the light output for a particular lamp-ballast system. |
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Name three reasons why the amount of light from a luminaire with fluorescent lamps decreases over time.
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Dirty, ballast factor changes, lumen depreciation
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You need to illuminate a whiteboard in a classroom. What type of luminaire would you use?
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Wall washer
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What are the two safety hazards that must be mitigated in any electrical design?
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Fire, shock
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What safety hazard will occur if the designer chooses a wire size that is too small?
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The wires will melt and potentially start a fire.
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What is the most common electrical service provided to residential guildings?
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120V/240V 3-wire service
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Suppose you placed a voltmeter between two points in a circuit panel as listed in the following table. The service provided to the panel is 120V/240V 3-wire service. Fill in the approximate voltage
Neutral to Phase A Phase A to Phase B Phase B to Ground Neutral to Ground |
Neutral to Phase A - 120V
Phase A to Phase B - 240V Phase B to Ground - 120V Neutral to Ground - 0V |
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What is the third prong on a 120V receptacle connected to?
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Ground
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What is the danger of disabling or not using the third prong of a standard 120V receptacle?
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Without the ground a short circuit could occur without tripping a breaker, potentially cause a fire.
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Name three reasons why it is important to run power wiring in conduit.
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protect wires, protect people from electricution from drilling into wires, organizing wires
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Which of the following applications require running power wiring in conduit: Residential, Commercial, Industrial?
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Commercial and Industrial
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What is the plastic cover around metal mire called?
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Insulation
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What is the most common service provided to large commercial and industrial buildings?
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120V/208V 4 wire service
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What should a volt meter read between the following?
Neutral to Phase A Phase A to Phase B Phase C to Ground Neutral to Ground |
Neutral to Phase A - 120V
Phase A to Phase B - 208V Phase C to Ground - 120V Neutral to Ground - 0V |
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You have a piece of electrical equipment that requires 120V and your installation has 120V/208V 4-wire service. What two leads would you connect to the equipment?
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Hot to Neutral
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You have a 3 Phase motore that requires 208V to operate. What conductors should you connect to the motor?
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A, B, and C
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Many 3-Phase motors do not have a neutral connection. Why not?
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The current sums up to Neutral = 0
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All 3-Phasemotors do have a ground connection. Whyiis that important and what should you connect that terminal to?
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In case of short, it will protect from shock. Ground
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In 120V/240V 3-wire service, which conductors should always have circuit breakers or fuses on them?
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A,B
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In 120V/240V 3-wire service, which conductors should never have circuit breakers or fuses on them?
Why not? |
Neutral
If the breaker on the neutral wire breaks but the first breaker does not powere will still be going to equipment. Could result in fire or shock. |
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In 120V/208V 4-wire service, which conductors should always have circuit breakers on them?
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A, B, and C
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In 120V/208V 4-wire service, which conductors should never have circuit breakers or fusese on them?
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Neutral
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If you have a question regarding what is acceptable in terms of electrical installation, what standard should you use?
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National Electric Code, NEC
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Why is it important to have a service disconnect panel?
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In case of a fire
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What is the function of a circuit breaker?
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Cuts service in case of too much current
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What is the function of a fuse?
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Cuts service in case of too much current
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What does a Ground Fault Circuit Interrupter do?
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Cuts powere, prevents shock by comparing current going and returning
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Does a circuit breaker protect against fire or against shock hazard?
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Fire
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Does a fuse protect against fire or againsdt shock hazard?
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Fire
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Does a GFCI device primarily protect against fire or against shock hazard?
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Shock
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What are the conductors between the service disconnect panel and a breaker panel called?
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Feeders
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What are the conductors between the circuit panel and luminaires or receptacles called?
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Branch Circuits
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A branch circuit has a piece of equipment that is rated for 10A. The circuit breaker that feeds the branch circuit is rated at 20A. What ampacity should the wire have?
Why? What is the hazard if the incorrect wire is chosen? |
20A, A breaker should always open before a wire receives too much current.
If something were to draw more than 10A through the wire without opening the breaker, the wire could melt causing a fire or shock risk. |
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Several pieces of electrical equipment are placed on the same branch circuit. If you know the rated current for each device, how can you find the total current for the entire branch?
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Add them all together
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What is the standard estimate for the current required by a 120V convenience receptacle?
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1.5A
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Name three locations where GFCE outlets are required.
Why do you think they are required in those locations? |
Bathroom, Kitchen, Garage
These locations are subject to potential harm from liquids. |
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In a resid3ence, what types of equipment are most likely to require 240V service?
Why? |
Dryers, ovens, anything that heats
Takes lots of power |
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If you examine a circuit panel that is supplied with 120V/240V 3-wire service, how could you tell which branch circuits use 240V?
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Double Breaker w/ on switch
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What rule do you use to determine where to put convenience receptacles in a room?
What is the safety reason for this rule? |
12 ft between receptacles maximum; receptacle with 6ft of any position
So chords are stretched accross large spans. |
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Does communication and control wiring need to be run in conduit?
Why or why not? |
No
If power wiring accidentally touched conduit it could send current through wires not meant to carry it |
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Is it acceptable to run communication or control wiring in the same conduit as power wiring?
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No, If power wiring accidentally touched conduit it could send current through wires not meant to carry it
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Suppose you have a relay with three terminals labeled COM, NO, and NC. What do those abbreviations stand for?
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Common, Normally Open, Normally Closed
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The coil of the relay is not energized. What resistance do yo uexpect between COM and NO?
What about COM and NC? |
infinite
zero |
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The coil of the relay is energized. What resistance do yo uexpect between COM and NO?
What about COM and NC? |
zero
infinite |
