Electrical

Determine the ampacity of a No. 2 AWG copper conductor with THHN insulation that will be used in a 480V, three-wire circuit in an environment with an average ambient air temperature of no greater than 86°F. (Ex 19.2)[NEC Table 310.15(B)(16)]

115A

An electrical box has a 14-3 w/ground NM cable entering and a 14-2 w/ground NM cable exiting a box. There is one clamp to hold the wires and one duplex receptacle in the box. What is the box volume needed?

18 cu. in.

If a 15A load is situated 100 ft. from its 120VAC power source what is the actual and percentage power loss in the circuit if 14ga copper wire is used? (Select both a voltage drop and percentage drop)[Ex. 18.2 &18.3, Table 18.8]

6.43% 7.71V

Constant exposure to high temperatures degrades the conductor insulation, so a conductor exposed tohigher temperatures will have a lower ampacity rating. Also, the ampacity of a conductor may need to beadjusted when conditions surrounding the conductors like ambient temperatures and __________ ofconductors in a raceway fall outside of normal ranges.

Also, the ampacity of a conductor may needto be adjusted when conditions surroundingthe conductors like ambient temperaturesand number of conductors in a raceway falloutside of normal ranges.42

Natural lighting is good for ________ lighting purposes but cannot provide the ________,________ light to perform tasks.

Natural lighting is for general lightingpurposes but cannot provide the controlledfocused light to perform activities

Neutral daylighting occurs in the range of ______ K to ______ K. A candle is about 1800Kand the noonday sun about 5500K

Neutral daylighting occurs in the range of4500 K to 6500 K. A candle is about 1800Kand the noonday sun about 5500K

In the question above what is the correct wire size that should be used?

10

Heat generated by current flow leads to a loss in power called power or line loss and can be computedfrom a known amperage or voltage and the resistance.Ploss = I²R =V²/R37. Example: If a load of 20A is 50ft from the 120V power source what is the line loss with 14ga wire?P = I²R = (20A)² • (2.57Ω/1000ft) • 100ft= 102.8W (power loss)P = EI = 120V • 20A = 2400W (power use)

102.8W / 2400W = 0.0428 0r 4.28%If we are limited to a 3% power loss then this wire is too small and excessive heating willoccur. A larger size wire should be used.A 20A load 50ft from the panel with 12ga wire has a 65W power loss.Power available: 2400W - 65W = 2335WUsing E=P/I; 2335W / 20A = 116.8V is OK, but 5 times the length would give 103.5Vwhich is outside the range of 110 - 130V.

If a 30A load is situated 200 ft. from its 240VAC power source what is the actual and percentage power loss in the circuit if 8ga aluminum wire is used? (Select both a voltage drop and percentage drop)[Ex. 18.2 &18.3, Table 18.8]

12.6V

An electrical box has (3)-120 V/20 A circuits fed with #12 THHN single conductors in conduit. (3 hot wires, 3 neutral wires and 1 ground wire.) Two of the circuits pass straight through the box, one circuit has a grounded switch on it. What is the box volume needed?

22.5 cu. in.

Determine the ampacity of a No. 10 AWG copper conductor with THHN insulation that will be used in a 240V, three-wire circuit in an environment with an average ambient air temperature of no greater than 100°F. (Ex 19.3)[NEC Table 310.15(B)(16)and Table 310.15(B)(2)(a)]

26.4A

In the question above what is the correct wire size that should be used?

4

Determine the ampacity of a No. 1 AWG aluminum conductor with THWN-2 insulation that will be used in a 240V, three-wire circuit in an environment with an average ambient air temperature of no greater than 110°F. Two similar circuits will be carried in the conduit. Assume that a shared neutral is not used. (Ex 19.3)[NEC Table 310.15(B)(16)and Table 310.15(B)(2)(a)]

80.0A

A branch circuit is the portion of the building wiring that extends from the ________ overcurrentprotection device to the point of ______________. An _________ is the point where current is taken tosupply an appliance, piece of equipment or a lighting fixture. So a branch circuit is the overcurrentprotection device the wiring and one or more outlets.94. Individual branch circuits serve one piece of equipment and come directly from the panel to areceptacle or the equipment. Ex: copy machine, freezer, sump pump.94. General Purpose branch circuits serve outlets for lighting or receptacles. General purpose circuitstypically supply power to lighting outlets and convenience receptacles which means they are either 15Aor 20A circuits. If a general purpose circuit feeds both fixed appliances and luminaires or portableappliances the total of the fixed appliances can be no more than 50% of the branch circuit rating.94. Appliance branch circuits serve outlets to which appliances are connected, and can be no more than20A. Ex: kitchen counters, refrigerator, microwave, washing machine95. A Multiwire branch circuit is a circuit where there are two or more hot conductors having a voltagebetween them and a common shared neutral. All conductors must originate from the same panelboard.Ex: A/C condenser, electric furnace, range, dryer.95. Life safety or critical branch circuits are connected to alternate power sources.

A branch circuit is the portion of the buildingwiring that extends from the finalovercurrent protection device to the point ofutilization.

The locations are classified as dry, damp and wet. From Article 100 - NECDry - not normally subject to dampness or wetness (temporarily during construction is okay)Damp - protected from weather and not subject to saturation with water or liquidsWet - underground, in concrete slabs or masonry, in direct contact with the earth; unprotected locationsexposed to weather16. Most conductor insulation is plastic, but in the past rubber covered with cloth was the norm but thatdeteriorated over time. Plastic wire insulation allows use up to 600V but different insulations havedifferent ratings like temperature or location. Common temperatures are 140°F, 167°F, and 194°F; or60°C, 75°C, and 90°C.19. A ________contains more than one conductor bundled together in a factory assembly of wires. Theouter sheathing encases and _________ the wires

A cable contains more than one conductorbundled together in a factory assembly ofwires.The outer sheathing encases and protects thewires.19

A color temperature less than ______ K provides warm lighting, reds and yellows; and colortemperature greater than ______ K provides cool lighting, blues and whites.

A color temperature less than 3500 Kprovides warm lighting, reds and yellows;and color temperature greater than 5000 Kprovides cool lighting, blues and whites.Neutral daylighting occurs in the range of4500 K to 6500 K. A candle is about 1800Kand the noonday sun about 5500K

Excessive heat as a result of high amperage draw will cause the insulation to degrade creating a lossof insulating value and the potential for faults. Heat is generated at equipment terminals due to resistanceand can damage the conductors if not dissipated, so circuit conductors are sized at the 140°F for less than100A and 167°F for over 100A.33. It is impossible to eliminate all heat from current flowing in a wire because of the resistance of theconductor, so some heat is tolerated. A conductor's __________ is the maximum current that it can carrycontinuously without exceeding the temperature rating of the insulation and sheathing materia

A conductors ampacity is the maximumcurrent that it can carry continuouslywithout exceeding the temperature ratingof the insulation and sheathing material.33

A ______________ clause is what allows an outdated electrical installation that does not meet the morestringent current standards to remain in use as long as it is not regarded as hazardous. An outdatedinstallation must only be changed if it is part of a ______________ project

A grandfather clause is what allows anoutdated electrical installation that doesnot meet the more stringent currentstandards to remain in use as long as it isnot regarded as hazardous.

A _______ is a device that generates light. (A light bulb is the glass that encloses theworking parts.)

A lamp is a device that generates light. (Alight bulb is the glass that encloses theworking parts.) Artificial

A large voltage drop not only results in equipment operating below rated capacity like a heater; butcauses lights to be dim or flicker, electronic equipment to malfunction. So with long conductor runs thesize of the conductor must be ___________ to counteract the inherent resistance in the conductor.

A large voltage drop not only results inequipment operating below rated capacitylike a heater; but causes lights to be dim orflicker, electronic equipment to malfunction.So with long conductor runs the size of theconductor must be increased to counteractthe inherent resistance in the conductor.35

Lamps are rated according to their efficacy, life, color temperature and rendition.22. A __________ is a complete lighting unit with all lamps, lenses, reflectors, ballasts and thehousing. (A light fixture is a luminaire less the bulb.)

A luminaire is a complete lighting unit with alllamps, lenses, reflectors, ballasts and thehousing. (A light fixture is a luminaire lessthe bulb.)

A minimum of _____ 20A circuit must be provided for the laundry room convenience receptacle andeach bathroom must have a ___________ 20A circuit for the receptacle in addition to any other circuits.(210.11 (C)). When any load operates for more than ___ hours at a time the load is deemed continuousand must have a circuit rating calculated at _____% of the circuit's connected load. This keeps the circuitbreaker from tripping.

A minimum of one 20A circuit must beprovided for the laundry room conveniencereceptacle and each bathroom must have adedicated 20A circuit for the receptacle inaddition to any other circuits. (210.11 (C))

A switch is a device placed between two or more electrical _____________ to safely and intentionally_______or ________ a circuit or redirect the path of the current in a circuit. Switches are rated bypurpose, voltage and amperage and classified for AC or DC. A safety switch is designed to reduce thepossibility of contact with bare electrical conductors and have current interrupting capability.55. There are two categories of safety switches:Heavy-duty - are designed for industrial, commercial, and institutional applications where safetyand performance are required. They may be fused or unfused.General-duty - are used for light industrial, general commercial and residential loads whereeconomy is desired. They serve motors, lighting, heating and appliances.57. Switches are identified with a combination of two terms: pole and throw.Pole - is the number of conductors being opened or closed.Throw - is the number of operations that can be performed.Therefore, a SPST switch opens or closes one conductor, a DPDT switch can direct twoconductors to two different paths.59. The most common switch is the SPST or just single pole switch, its designation is (S). A single poleswitch can control an individual "outlet" in a parallel configuration, or a number of outlets (up to theamperage or wattage rating) in a series configuration

A switch is a device placed between two ormore electrical conductors to safely andintentionally open or close a circuit orredirect the path of the current in a circuit.

GFCI's - where required:210.8(A) - _____ 125 volt, single phase, 15- and 20-ampere receptacles installed in the locationsspecified...shall have ground-fault circuit-interrupter protection for personnel.(1) Bathrooms(2) Garages, Accessory buildings, (storage)(3) Outdoors except ice melting(4) Crawl Spaces at or below grade(5) Unfinished basements, (storage)(6) Kitchens receptacles on countertops(7) Sinks - when installed within 6ft of the outside edge of the sink(8) Boathouses(9) Bathtubs or shower stalls - when installed within 6ft of the outside edge of the bath tub orshower stall(10) Laundry areas(D) Dishwasher Circuit422.49 - Cord-and plug-connected high-pressure spray washing machines422.51(A) - Cord-and plug-connected vending machines shall have a portable GFCI (B)otherwise a GFCI circuit.422.52 - Electric Drinking Fountains590.6(A) - Temporary power including generators less than 15-kW680.21(C) - Outlets supplying pool pumps680.22(A)(2) - Outlets for circulating pumps(B)(2)-(4) - Luminaires and Paddle Fans680.27(B)(1) - Electric pool covers680.42 (A)(2) - Outdoor spa with cord680.43 (A)(2) - Receptacles within 10ft.(3) Receptacles that supply power680.58 - Within 20ft of fountain edge114. Right behind the danger from electrocution is the danger from fire caused by electrical wiring. Anarc fault is an unintentional electrical discharge characterized by low and erratic current. Arcing causeshigh intensity heat and burning particles which can easily ignite combustibles.

All 125 volt, single phase, 15- and20-ampere receptacles installed in thelocations specified...shall have ground-faultcircuit-interrupter protection for personnel.

Any connected loads above ____A are usually placed on a dedicated circuit. Often these circuits feedfixed appliances. Small appliance circuits serve two or more outlets to which only (portable) appliancesare connected. Code requires that a minimum of _____ small appliance circuits be installed in a kitchen,dining room, breakfast room or pantry (NEC 210.52) no lights may be connected to this circuit

Any connected loads above 20A are usuallyplaced on a dedicated circuit. Often thesecircuits feed fixed appliances.

Any service exceeding 250V or 250A must be located in a separate room used for no other purpose(except telecom equipment) and it must have a 1hr fire rating unless ___________. Panels are not allowedin clothes closets or in bathrooms.Clearances for overhead services:23. In order to maintain safe working clearances from service lines, a minimum height is dictated bycode. 18' over roadways, 12' above driveways, 10' above sidewalks, 8' above low slope roofs, and 3'above steep slope roofs. (NEC 230.24)Depth of cover for underground services:23. For underground service the depth of cover varies from 6" to 42" depending on the voltage, conduit ortype of cable. (NEC 300.5 or 300.50)

Any service exceeding 250V or 250A must belocated in a separate room used for no otherpurpose (except telecom equipment) and itmust have a 1hr fire rating unlesssprinklered.

Copper and aluminum are used to make building wire. Copper is a better conductor but aluminumhas an advantage in the weight area. As a result an aluminum conductor must be of a __________ sizethan a copper conductor in order to be rated for the same current capacity.

As a result an aluminumconductor must be of a larger size than acopper conductor in order to be rated forthe same current capacity.

Bonding jumpers are required when flexible conduit is used. Code specifies the minimum sizeequipment grounding conductors for raceways and equipment. These conductors are routed in the sameraceway or cable as the circuit conductors. Where more than one circuit is installed in a raceway, only_____ grounding conductor is required.46-47. Double insulation is a term applied to appliances or power tools that protect the user from anelectrical _______ by creating a nonconducting barrier between the user and the electrical componentsinside. An appliance or tool has _____ levels of insulation between electrical parts and the outside. As aresult double insulated tools and appliances are allowed to have a ______-prong plug

Bonding jumpers are required when flexibleconduit is used.The Code specifies the minimum sizeequipment grounding conductors forraceways and equipment. Theseconductors are routed in the sameraceway or cable as the circuitconductors. Where more than one circuitis installed in a raceway, only onegrounding conductor is required.Double insulation is a term applied toappliances or power tools that protect theuser from an electrical shock by creating anonconducting barrier between the userand the electrical components inside.46An appliance or tool has two levels ofinsulation between electrical parts and theoutside. As a result double insulated toolsand appliances are allowed to have a two-prong plug.47

By definition panelboards serving lighting and convenience receptacles that have at least _____% ofthe circuits rated at 30A or less are called lighting and appliance panels.

By definition panelboards serving lighting andconvenience receptacles that have at least10% of the circuits rated at 30A or less arecalled lighting and appliance panels.

Chromatic light is the term for a light that emits a fairly even distribution of _____wavelengths of light, although most sources of light are not _______ chromatic

Chromatic light is the term for a light thatemits a fairly even distribution of allwavelengths of light, although mostsources of light are not fully chromatic.

Efficacy is the ratio of the light _______ to the electrical power consumed (including theballast if applicable,) and is expressed in lumens per watt (lm/W or LPW

Efficacy is the ratio of the light output to theelectrical power consumed (including theballast if applicable,) and is expressed inlumens per watt (lm/W or LPW)

Enclosures:76. Electrical boxes are metallic or non-metallic that hold devices such as _________ or ______________and provide a place to safely make wiring connections.77. Boxes come in four basic shapes; square, rectangular, octagonal, and round.78. Because some metal boxes are designed to be "ganged" together; boxes that hold more than onedevice are called two-gang, three-gang, four-gang, etc.79. Junction boxes are the same type but used only to enclose a wiring connection and contain no device.A pull box is a box that allows access to a raceway.80. Knockouts allow wiring to enter the box.81. Cover plates are made of plastic for switches or receptacles and of the same material as the box forjunction boxes and pull boxes.82. Lighting fixtures attach directly to the boxes

Electrical boxes are metallic or non-metallicthat hold devices such as switches orreceptacles and provide a place to safelymake wiring connections.

For a three-phase system, the issue is the same; a three-phase circuit draws equally but a single-phasecircuit may cause an imbalanced load.61. In the case where the loads can be adequately balanced, the code allows for a derating factor for theneutral because it will only carry the unbalanced load.62. A raceway is an enclosed channel such as a conduit, tube or gutter designed to hold wires, cables, orbusbars. In some cases the raceway is bonded to provide the ground.69. Conduit is cut, bent and threaded on the jobsite. Cuts are made with a saw, the interior is reamedclean of any burrs and threaded if needed and the fittings are attached. Bends are made with a conduitbender that keeps the tube from kinking. Plastic conduit is heated to make it flexible.All raceways are installed as a complete system before any wires are pulled. (NEC 300.18) The numberof wires depends on the size. (NEC Informative Annex C)

Enclosures are specified by their application and use.NEMA 1 - Interior, Dry LocationsNEMA 3R - Exterior Raintight, Damp LocationsNEMA 4X - Exterior, Waterproof, Wet LocationsNEMA 7 - Hazardous Locations79. A busway is a standardized, factory assembled enclosure that consists of an outer housing, bus barsand insulation. They are used in service equipment or as feeders because they can carry a large amount ofcurrent with little voltage drop. Busways are expensive so their use is limited to industrial applications, onthe other hand they can be salvaged and moved easily. Electrical Service Systems - 2990:46381. A wireway is a sheet metal or plastic trough designed to serve as a housing to enclose and protectconductors. Access to the wireway is by a hinged or removable cover. Wireways are a easy andconvenient way to run large conductors

A shared neutral that is not current carrying is not counted. (the neutral on a single 120V circuit is nota shared neutral) However, on a four-wire, three-phase, wye-connected system the shared neutral must becounted as a current-carrying conductor. Equipment grounding conductors are _____ counted.Putting it all together it looks like this: Iampacity = Inormal (Ft) (FN)52. The insulation on small and medium size wires is color coded for easy identification. Largerconductors use paint or colored tape for marking. Multiple hot conductors in a raceway must marked by astripe. Color coding applies to wire sizes 6 AWG and smaller. The grounding conductor must be colorcoded green, green with yellow stripe(s), or may be bare on small conductors in a cable. Code makes nofurther distinction as to the color of ungrounded conductors with the following exceptions: neutral mustbe white or grey and the wild leg on a 240V Δ must be colored orange. (NEC 110.15)The usual progression of colors for single phase is: black, red, blue, yellow.For three phase: brown, orange, yellow.Pink, purple and tan are also available

Equipment grounding conductors are notcounted.

____________ lamps are strong in reds, greens and blues

Fluorescent lamps are strong in reds, greensand blues.

GFCI's come in three forms, the most common being the one installed instead of a duplexreceptacle. When installed at the _____________ of a circuit, all outlets downstream of the GFCI can beprotected.

GFCI's come in three forms, the mostcommon being the one installed instead ofa duplex receptacle. When installed at thebeginning of a circuit, all outletsdownstream of the GFCI can be protected.107A GFCI breakerwill also protect anentire circuitincluding the wiringfrom the box.

General purpose circuits typically supply power to lighting outlets and convenience receptacles whichmeans they are either ____A or ____A circuits. If a general purpose circuit feeds both fixed appliancesand luminaires or portable appliances the total of the fixed appliances can be no more than _____% of thebranch circuit rating.

General purpose circuits typically supplypower to lighting outlets and conveniencereceptacles which means they are either15A or 20A circuits.If a general purpose circuit feeds both fixedappliances and luminaires or portableappliances the total of the fixed appliancescan be no more than 50% of the branchcircuit rating.97

Grounding of a branch circuit enables current to take an alternate path back to the overcurrentprotection device in the case of a short circuit. This is accomplished by a separate, additional wire calledthe grounding conductor which is connected to the housing, cabinet, enclosure or box. Without thisadditional path, current could flow through a _______ that touched a faulty appliance.

Grounding of a branch circuit enables currentto take an alternate path back to theovercurrent protection device in the caseof a short circuit.

The grounding conductor does not normally carry current, but links to ground all the metal frames orhousings of equipment and any metal boxes containing outlets and switches. If needed the groundingconductor can safely carry current to ground in case of a ______________ strike or a ________ in thecircuit, appliance, device or equipment

If needed the grounding conductor can safelycarry current to ground in case of alightning strike or a fault in the circuit,appliance, device or equipment.32

In a two-wire branch circuit the grounded conductor caries a current equal to the load, therefore thegrounded conductor must be of the ______ ampacity as the ungrounded (hot) conductor. The neutralconductor performs the function of a grounded conductor for at least _____ ungrounded conductors from__________ phases such as in a multi-wire branch circuit, feeder or service

In a two-wire branch circuit the groundedconductor caries a current equal to theload, therefore the grounded conductormust be of the same ampacity as theungrounded (hot) conductor.The neutral conductor performs the functionof a grounded conductor for at least twoungrounded conductors from differentphases such as in a multi-wire branchcircuit, feeder or service. 56

Grounding:30. In an electrical system, grounding protects building occupants and electrical equipment. Thegrounding system begins with the ground __________ which is in direct contact with the _________.The grounding conductor is a _____________ conductor that connects the ground to the grounding busbar to the neutral bus bar in the service equipment or main panelboard

In an electrical system, grounding protectsbuilding occupants and electricalequipment. The grounding system beginswith the ground electrode which is indirect contact with the earth. Thegrounding conductor is a continuousconductor that connects the ground to thegrounding bus bar to the neutral bus barin the service equipment or mainpanelboard. 3019.5

In any application where more than ______ possible switches could be used as service disconnects, a__________ main service disconnect must be provided to disconnect power to the building or panel.(NEC 230.71)Clearances about equipment:21. Code specifies that all service equipment and electrical panels have a clear area around them 30"wide, 36" deep and from floor to ceiling.Service and panel locations:

In any application where more than six possibleswitches could be used as service disconnects,a single main service disconnect must beprovided to disconnect power to the building orpanel.

In multiwire branch circuits where there are two or more hot conductors and a neutral, the commonneutral carries current only when ____________ loads exist on the hot conductors

In multiwire branch circuits where there aretwo or more hot conductors and aneutral, the common neutral carriescurrent only when dissimilar loads existon the hot conductors.

In the US, the ______________ _______________ _______ (NEC) is the model code that is adoptedby nearly every jurisdiction with local modifications. The code does not become law until it is adoptedby the local government authority.

In the US, the National Electrical Code (NEC)is the model code that is adopted by nearlyevery jurisdiction with local modifications.The code does not become law until it isadopted by the local government authority.

Incandescent lamps emit visible light as a result of _________ a __________ filament toincandescence. They have low lamp cost, reliability, familiarity, and good color rendition, buthave ________ rated life and _______ efficacy. They are still the best for applications needingexcellent ________ _________ like retail sales, restaurants, and galleries.

Incandescent lamps emit visible light as aresult of heating a resistance filament toincandescence.They have low lamp cost, reliability,familiarity, and good color rendition, buthave short rated life and poor efficacy.They are still the best for applicationsneeding excellent color rendition like retailsales, restaurants, and galleries

Grounded & Ungrounded: In any single-phase branch circuit, a grounded conductor serves as thegrounded leg of a circuit. It completes the circuit by connecting the ungrounded conductor through theload to _______. In this type of circuit, the grounded conductor is considered to be a current carryingconductor because it serves as a return path to the circuit's power source

It completesthe circuit by connecting the ungroundedconductor through the load to ground.

Product Standards:14. The National Electrical Manufacturing Association (NEMA) is the leading trade organization in theUS that represents the interests of electrical manufacturers. NEMA has been developing standards since1926 and is one of the leading standards development organizations in the world. It contributes to an_________ marketplace and ensures public _________.

It contributes to an orderly marketplaceand ensures public safety.14

Lamps are one of two kinds, ____________ or ____________ _________. Gaseousdischarge lamps are further divided by _____ or ________ pressure. Fluorescent and low-pressure sodium are low pressure and mercury vapor, metal halide, and high-pressure sodium arehigh pressure.

Lamps are one of two kinds, incandescent orgaseous discharge. Gaseous dischargelamps are further divided by low or highpressure. Fluorescent and low-pressuresodium are one type and mercury vapor,metal halide, and high-pressure sodium arethe other type.

Many commercial buildings are supplied with 480V Δ, this allows for the connection of step-downtransformers that yield 208V Y/120V or a 480V/277V Y system that is easy to generate a 208V/120V Ywhere both sets of voltages are utilized. Equipment that is designed to run on ________ will run on______ but not the opposite because even though the voltages are the same the delta lacks the neutral ofthe wye configuration.

Many commercial buildings are supplied with480V Δ, this allows for the connection ofstep-down transformers that yield 208VY/120V or a 480V/277V Y system that iseasy to generate a 208V/120V Y where bothsets of voltages are utilized. Equipment thatis designed to run on delta will run on wyebut not the opposite because even thoughthe voltages are the same the delta lacks theneutral of the wye configuration.

Monochromatic light is visible light in a _________ range of wavelengths, the type ofwavelength influences the color perception. When a monochromatic light illuminates a surface,only the color _________ by the light source will illuminate.

Monochromatic light is visible light in anarrow range of wavelengths, the type ofwavelength influences the color perception.When a monochromatic light illuminates asurface, only the color emitted by the lightsource will luminate.

Permits:7. Most municipalities also require that a ________ be issued before installing any electrical systems on aproject. A complete electrical construction __________ may be required for review by a plans examinerbefore a project begins. Inspectors check the project at intervals during the construction process; they aretypically the rebar bonding, service, rough and final inspections

Most municipalities also require that a permitbe issued before installing any electricalsystems on a project. A completeelectrical construction drawing may berequired for review by a plans examinerbefore a project begins.Inspectors check the project at intervalsduring the construction process, they aretypically the rebar bonding, service, roughand final inspections. 7

Licenses:6. Most municipalities require that anyone who engages in the business of installing electrical systemsmust be __________, usually by the state or province. This usually means a minimum number of yearsof experience and the passing of a _________ test that deals with the code and with business practices.Without licensure there is no protection for the consumer

Most municipalities require that anyone whoengages in the business of installingelectrical systems must be licensed,usually by the state or province. Thisusually means a minimum number ofyears of experience and the passing of awritten test that deals with the code andwith business practices. Without licensurethere is no protection for the consumer.6

Most switches and receptacles are wall mounted, and the code _________ state any particular height.By industry convention, switches are mounted 48" to center above finished floor. Countertop receptaclesare mounted at 44" to center and convenience outlets 16" - 18" to center. Neither does code state whichway an outlet is to be installed (ground up or down)

Most switches and receptacles are wallmounted, and the code doesn't state anyparticular height.

Much of the radiation from incandescent lamps is in the ___________ spectrum which iswhat causes the low efficacy. The warm colors have been accepted for many years as the normfor indoor lighting.37. Incandescent lamps have wattages between 3 and 1000W and voltages from 6 to 277V with120, 125 and 130V being the most common. Lamps are also designated by their ___________,such as A, R, T, ER, PAR and by their size in eighths of an inch.

Much of the radiation from incandescentlamps is in the infrared spectrum which iswhat causes the low efficacy. The warmcolors have been excepted for many yearsas the norm for indoor lighting.As an incandescent lamp burns, the filamentevaporates and deposits on the inside ofthe bulb, deterioration also occurs overtime and as a result the lamp's outputdiminishes to about 85% over time

Overcurrent protection devices are typically 150 - 200% of the rated primary current of thetransformer are used to protect the primary transformer feeders. The secondary conductors usually have arating of 125%. System grounding of the transformer is required to remove static electricity and in casethe transformer winding come in contact with the enclosure. The grounding conductor size is based on thesize of the _________.

Overcurrent protection devices are typically150 - 200% of the rated primary current ofthe transformer are used to protect theprimary transformer feeders. The secondaryconductors usually have a rating of 125%.System grounding of the transformer isrequired to remove static electricity and incase the transformer winding come incontact with the enclosure. The conductor isbased on the size of the feeders.

Power distribution panelboards feed subpanels, motors, or transformers, and other loads but not lightsand receptacles.17. In a single panelboard no more than _____ overcurrent protecting devices may be used for lighting orreceptacles.

Power distribution panelboards feedsubpanels, motors, or transformers, andother loads but not lights and receptacles.In a single panelboard no more than 42overcurrent protecting devices may be usedfor lighting or receptacles. 17

Two Types of Grounding:35-36. System grounding is the part of the system that protects against electrical shock, lightning andfires. System grounding bonds all of the electrical system components together at the neutral bus of theservice equipment. The grounding system must be connected to some or all of these building components.Approved grounding methods:An underground metal water pipe in direct contact with the earthThe metal frame of a building or structureConcrete encased electrode in direct contact with the earthGround ring or plate

Rod or pipe electrodeLocal metal underground system or structureA gas line cannot be used for an electrode!

CM circular mils - Metric has forced its way in and k is for kilo, the SI unit of 1000), the _________ thenumber the ________ the wire. The sizes range from 250 - 2000. ___________ the number __________the size of the wire

Since a mil is 1/1000 in; one circular mil(cmil) is equal to the cross-sectional areafor a 0.001 circle which is pretty small.Circular mils are easier, to keep the numberssmall kcmil is used, (sometimes MCM), thelarger the number the bigger the wire.

Small air-cooled transformers can be mounted almost anywhere, but large transformers are located inrooms or ________. Transformer vaults must have a minimum 3hr fire rating unless sprinklered (thenonly 1hr), the doors must swing _____, have panic bars, and be provided with _______ so that they areaccessible only to qualified persons. The vault cannot be used as a storage room and must be properlyventilated.

Small air-cooled transformers can be mountedalmost anywhere, but large transformers arelocated in rooms or vaults.Transformer vaults must have a minimum 3hrfire rating unless sprinklered (then only 1hr),the doors must swing out, have panic bars,and be provided with locks so that they areaccessible only to qualified persons.

59.Switches are always wired to control (switch) the ungrounded (hot) conductor.60. To control an outlet from two points a three-way switch (S3) is used. A three-way switch is really justa SPDT switch.60. To control an outlet from more than two locations a four-way switch (S4) is used. A four-way switchis required for all additional points at which it is desired to control the outlet. All four-way switches mustbe wired between two three-way switches.61-70. Take some time to look at the diagrams. A three-way switch has three (3) terminals. Twoare brass-color and one is colored black. The black one is the "Common" terminal because it iscommon to the other two terminals. The other two terminals are for the "Traveler" wires. Thesewires cause the current to travel between the two switches. The travelers are NEVER connectedto the source power or the load they only go between the traveler terminals of the 3-way switches.In the pictures they are black and red. That leaves us with the common terminal. The commonterminal is ALWAYS connected to either the source power or to the load. It doesn't matter whichswitch is connected to which, it's a matter of physical location and convenience as to which oneis the source and which one is the load. The neutral wire is simple; it just goes from the sourcepast all of the switches until it reaches the load. Following these rules will result in a 3-wayswitch installation that works every time. Otherwise, usually one switch will work and one won't.

Specialty switches -The most common is the dimmer switch, it controls the flow of power to the outlet. Old time dimmersused switch the power off and on rapidly, this worked fine with incandescent bulbs but not fluorescentlights. Current dimmers can be designed to work with CFL, LED and some electronic ballasts as well.Keyed switches for safety or security. Timer switches come in various forms; some are a simplecountdown style while others may be set to operate on a specific cycle or at different hours or days.Photocells sense the presence or absence of light and switch outlets accordingly. Occupancy/Motionsensors are used to switch on a light (typically) when a person walks into a room. Infrared sensors detecta moving heat source and switch on. Ultrasonic sensors use sound to create a field and sense any changein the field of sound and switch on

Equipment Design:15. Switches for large areas with numerous lighting fixtures that would require many switches may havethem centralized in a type of panelboard called a __________ control panel. Some of these panels areremote or computer controlled.

Switches for large areas with numerouslighting fixtures that would require manyswitches may have them centralized in atype of panelboard called a lighting controlpanel.

Drawings:8-10. Electrical construction drawings show the layout and design of the electrical installation. Acomplete set of drawings should include the following:1. Labeling criteria2. Lighting floor plans indicating conduit and wire sizes.3. Power floor plans with conduit and wire sizes indicating switches and equipment.4. Exit signs, egress lighting, locations and power supplies5. Panelboard schedule6. Lighting fixture schedule

Symbol scheduleSpecifications will include:1. Raceway and conduit2. Wire and cable3. Electrical boxes and fittings4. Electrical connections5. Electrical wiring devices6. Circuit and motor disconnects7. Hangers and supporting devices8. Electrical identification9. Service entrance and details10. Overcurrent protection11. Switchboards, panelboards, grounding12. Transformers, motor controls

The 80% rule is used in many cases of circuit design so that the limit of connected loads on a circuit is_____% of the maximum circuit rating (20A•120V = 2400VA•0.80 = 1920VA) A continuous operatingload such as fluorescent lighting is limited to 80%. A portable appliance is limited to 80%. A receptacle is1.5A each and limited to 80%. For a 15A circuit, 8 receptacles max. and for a 20A circuit 10 receptaclesmax.

The 80% rule is used in many cases of circuitdesign so that the limit of connected loadson a circuit is 80% of the maximum circuitrating (20A•120V = 2400VA•0.80 = 1920VA)

The correlated color temperature of a light source is the temperature at which a heated blackbody _________ the color of the light source in question.

The CCT of a light source is the temperatureat which a heated black body matches thecolor of the light source in question.A color temperature less than 3500 Kprovides warm lighting, reds and yellows;and color temperature greater than 5000 Kprovides cool lighting, blues and whites.Neutral daylighting occurs in the range of4500 K to 6500 K. A candle is about 1800Kand the noonday sun about 5500K

The NEC is revised every _______ years and then it is reviewed before being adopted. This may meanthat although there is a new code published it may not be adopted immediately and may not be currentlyin effect.

The NEC is revised everythree years and then it isreviewed before beingadopted. This may meanthat although there is anew code published itmay not be adoptedimmediately and may notbe currently in effect.

The ambient temperature is the temperature of the surrounding _________, it may be air or soil. Asthe ambient temperature rises, less current generated heat is needed to reach the temperature rating of theinsulation. The ambient temperature rating is the normal temperature range in which the conductor is tobe used. Conductor ampacity is adjusted for temperatures below 78°F and above 86°F.44. A temperature correction factor (Ft) for conductors is based on the ambient temperature where theconductor is to be used. If a conductor is used in a higher temperature then Ft is less than 1 so a largerconductor is needed; on the other hand if a conductor is used in a lower temperature the Ft is greater than1 and there is less concern about the heat generated by the conductors.48. When several current-carrying conductors are contained in a raceway or cable, the temperature willincrease under normal loading conditions. The additional heat causes a conductor surrounded by severalother heat generating conductors to exceed the temperature rating more easily. As a result the ampacity ofa conductor grouped with several other conductors is influenced by the ambient heat.

The ambient temperature is the temperatureof the surrounding medium, it may be air orsoil. As the ambient temperature rises,less current generated heat is needed toreach the temperature rating of theinsulation. The ambient temperature ratingis the normal temperature range in whichthe conductor is to be used.

The branch circuit rating is determined by the _____________ protection device that is used to protectthe wiring in the circuit from excessive current flow. The connected load is the sum of all the loads on acircuit found by adding the connected VA load for each outlet. Resistive equipment has a W=VA, butanything that has a motor will have a VA greater than the W.

The branch circuit rating is determined by theovercurrent protection device that is usedto protect the wiring in the circuit fromexcessive current flow.

The color rendering index (CRI) rates a color ___________ of a light source to a referencelamp. The reference lamp emits light over the full visible light spectrum at the same colortemperature as the light source being tested. The light source is compared at eight specific colorsand rated by how closely it compares to the test lamp.31. Lamp life is the median life expectancy of a lamp and is the cumulative time that elapsesbefore 50% of a representative group of lamps fails and the rest continue to operate.32. Lamp life generally decreases each time a lamp is turned off and on. A continuously lit lampwill last much longer than one that is switched off and on regularly; this does not mean leaving alight burning in an unused space will save money. The life of incandescent lamps will beaffected by the voltage they operate at vs. the voltage they were designed for. This may lead todecreased light output.

The color rendering index (CRI) rates a colordistribution of a light source to a referencelamp.

The conductors served by this neutral must measure the voltage between the _____ conductors and be equipped with a double or triple pole breaker or fuses. Sometimes this conductor is called the sharedneutral and it must always be insulated because it may carry current. The neutral is connected to ground atthe transformer and at the service entrance. In a sub-panel it is isolated from ground

The conductors served by this neutral mustmeasure the voltage between the hotconductors and be equipped with adouble or triple pole breaker or fuses.

The design goal of incandescent lamps is to balance ______ ______ with efficacy. Thehotter the filament, the ______ efficient the lamp is at converting electricity into light and thewhiter the light; but the hotter operation __________ lamp life. Incandescent filaments reachtemperatures between 2300 - 3000 K and produce visible light mostly in the red, orange andyellow spectrums.

The design goal of incandescent lamps is tobalance lamp life with efficacy. The hotterthe filament, the more efficient the lamp isat converting electricity into light and thewhiter the light; but the hotter operationreduces lamp life.Incandescent filaments reach temperaturesbetween 2300 - 3000 K and producevisible light mostly in the red, orange andyellow spectrums.

The electrical code specifies the __________ provisions that must be met to protect people andproperty from the improper use of electricity and electrical equipment. It applies to both the______________ and ______________ of electrical equipment

The electrical code specifies the minimumprovisions that must be met to protectpeople and property from the improper useof electricity and electrical equipment.

Equipment grounding refers to the grounding conductor that connects the noncurrent carrying metalcomponents of equipment. This is done by installing an additional grounding conductor or bypermanently bonding the metal components such as metallic conduit to form a good conductive path.39. Equipment grounding extends from the outlets to the service equipment.41. The equipment grounding conductor is a ______ or insulated ________ colored wire that bonds theoutlets, raceway, enclosures, motor frames and appliances. All receptacles must be of the grounding typeand must be connected to the equipment grounding conductor. If properly bonded a metal ___________can serve as the means of equipment grounding

The equipment grounding conductor is a bareor insulated green colored wire that bondsthe outlets, raceway, enclosures, motorframes and appliances.All receptacles must be of the grounding typeand must be connected to the equipmentgrounding conductor.If properly bonded a metal raceway can serveas the means of equipment grounding.41

The measurement of the perceived power of light is expressed in lumens (lm) which is theamount of light striking one _______ ______.

The measurement of the perceived power oflight is expressed in lumens (lm) which isthe amount of light striking one square foot.

The neutral carries only the _____________ part of the load, but if the loads on different circuits are Electrical Service Systems - 2990:463uneven because of differing use or poor design, a high load can __________ the neutral ___________tripping the overcurrent protection.59. To prevent this, the loads are divided as __________ as possible between the hot circuits so little orno current flows through the neutral.

The neutral carries only the unbalanced partof the load, but if the loads on differentcircuits are uneven because of differinguse or poor design, a high load canoverheat the neutral without tripping theovercurrent protection. 58

The perceived color of an object depends on the dominate ___________ that are __________from it. A surface that reflects all wavelengths appears ________ and a surface that absorbs allwavelengths appears ________. A __________ surface reflects only the wavelengths that make Electrical Service Systems - 2990:463up its own _______.

The perceived color of an object depends onthe dominate wavelengths that arereflected from it.A surface that reflects all wavelengthsappears white and a surface that absorbsall wavelengths appears black.A colored surface reflects only thewavelengths that make up its own color.Any other wavelengths are absorbed.

The percentages of all three factors must total 100%. The type of light transmitted, theproperties of the surface receiving it, and the angle at which the light is received determine theamount of each one of these components. __________ light is widely spread or scattered like ahazy day. _________ light is strong and focused and shadows are well defined

The percentages of all three factors musttotal 100%.The type of light transmitted, the propertiesof the surface receiving it, and the angle atwhich the light is received determine theamount of each one of these components.Diffuse light is widely spread or scatteredlike a hazy day. Direct light is strong andfocused, where shadows are well defined.

The purpose of lighting is to make a space _______ no matter the time or location. Goodlighting has the right quantity of light with excellent ______ rendition, and minimal ________

Thepurpose of lighting is to make a spaceusable.

There is a correlation between the color of light emitted by a light source and the____________ of the emitter. If a theoretical "black body" is heated enough it begins to_____________ or give off light

There is a correlation between the color oflight emitted by a light source and thetemperature of the emitter. If a "blackbody" is heated enough it begins toincandesce or give off light. First it turnsred, then orange, yellow, white and finallyblue.

When locating overcurrent protection in a panelboard it is important to try to balance the anticipatedloads so that each busbar is carrying a similar load. This is most often a problem with _______ phaseloads.Grounded and Grounding Conductors in Panelboards:18. In the main service panelboard, the neutral and the grounding conductors are bonded together. In asubpanelboard the neutral is isolated from the ground and the neutral busbar is not bonded to theenclosure."6 switch rule"

This is most often aproblem with single phase loads.

Total reliance on natural light is _________ because as the sun ________ during the day somewindows receive direct sunlight during the morning or afternoon or all day and some get none atall. On cloudy days all light is _________ light and at night there is none

Total reliance on natural light is complexbecause as the sun moves during the daysome windows receive direct sunlightduring the morning or afternoon or all dayand some get none at all.

All electrical connections must be made in a protective enclosure, box, panelboard, fixture orappliance. Every switch, outlet, and connection must be made in a box, and every lighting fixture mustbe mounted on a box. All wiring must begin or end in a panelboard or box. Junction boxes must bemounted so that the cover plate is visible and readily accessible. (NEC 314) While the code doesn'tspecify which box to use for which purpose, industry practice ends up dictating what the uses are.85. What the code does say is how many conductors may be in a box, the more conductors or the largerthe size, the more room is required in the box.86. Each conductor that runs through the box is counted as one and each conductor that terminates in thebox is counted as one. The grounding conductor is counted as one no matter how many there are andfixture wires are not counted at all. Any device that fits into the box is counted as double volume. (NEC314.16)

Volumes based on NEC Table 314.16(B)• 14 AWG = 2.00 in³• 12 AWG = 2.25 in³• 10 AWG = 2.50 in

When light strikes a surface it is illuminated and the amount of light striking a surface is____________. The light must be reflected in the direction of the viewer in order to be seen; thisis _____________ and is how bright an object appears

When light strikes a surface it is illuminatedand the amount of light striking a surfaceis illuminance.The light must be reflected in the direction ofthe viewer in order to be seen; this isluminance and is how bright an objectappears.

When more than three current-carrying conductors added to a raceway or bundled in a cable, theampacity of a current-carrying conductor must be ___________ to compensate for the additional heat. Abundling correction factor (FN) must be applied for four or more conductor in a raceway or cable. For 4-6 it is 0.80; for 7-9 it is 0.70, for 10-20 it is 0.50. The number of current-carrying conductors includesany ungrounded or grounded conductors.

When more than three current-carryingconductors added to a raceway or bundledin a cable, the ampacity of a current-carrying conductor must be decreased tocompensate for the additional heat.

White light renders all colors evenly, but light sources do not produce an _______distribution of wavelengths across the light spectrum.

White light renders all colors evenly, but lightsources do not produce an evendistribution of wavelengths across the lightspectrum.

Wire can be_______ (one piece) or __________ (multiple pieces). In buildings #20 through #8 isusually solid and #6 and above are usually stranded, except ground wire which is #4 solid bare copper

Wire can be solid (one piece) or stranded(multiple pieces).

Conductors are insulated to provide electrical isolation, but all insulation is not the same. Wire usedoutdoors is subjected to many factors so the insulation must be _____________ and _______________________ or may have to withstand being __________ in the soil

ire used outdoors is subjected to manyfactors so the insulation must be waterproofand sunlight resistant or may have towithstand being buried in the soil

Utilization Equipment:48. Utilization equipment is a broad term for any electrical or electronic machine or instrument designedto perform a mechanical, chemical, heating/cooling or lighting function through the use of electricalenergy.49. An appliance is a piece of end-use utilization equipment designed to perform a specific function likecooking, cleaning or space conditioning. Ranges, refrigerators, washers, dryers, blenders, toasters, andhair dryers are appliances. Fixed appliances are permanently attached, Stationary are used in one placebut can be potentially moved and portable appliances can carried about and moved.50. A device is a component that is designed to carry but not use electricity. This includes componentssuch as switches, receptacles and relays. An outlet is the location in a branch circuit where electricity isused. A lighting outlet provides power to a light fixture. Outlet - point at which current is taken to supplyutilization equipment. (Art.100)51. A receptacle is a female connecting device with slotted contacts installed at an outlet or on a piece ofequipment intended to easily establish an electrical connection with the inserted plug.51. A plug is a male connecting device with two or more prongs that are inserted in to the receptacle toconnect with an electrical circuit. A plug is usually connected to a flexible cord that is attached to theappliance.52. Different receptacle and plug combinations are tied to specific uses such as those for clothes dryersand ranges. The screw terminals on receptacles are color coded for ease of use. Brass colored screws arefor any ungrounded conductors, silver colored screws are for the grounded or neutral conductor and green

is for the equipment grounding conductor. Only receptacles marked CO/ALR are approved for aluminumconductors.53. This is a chart of some of the different styles of plugs and receptacles. Each one is different toprevent a piece of equipment from being plugged into a receptacle of the wrong voltage,amperage or phase. This protects both the user and the equipmen

For small and medium conductors the American Wire Gauge (AWG) is used. AWG is typical of most "gauge" designations. The _________ the number, the _________ the wire. The sizes range from 36 to0000. An increase of ____ in the AWG number gives a wire about twice the size.

larger the number the smaller the wire, increase of 6

For large conductors circular ______ are used. Since a mil is 1/1000 in; one circular mil (cmil) is equalto the cross-sectional area for a 0.001 circle which is pretty small. Circular mils are easier to use. To keepthe numbers small kcmil is used, (the old designation was MCM - M the Roman numeral for 1000 and

mils

_____________ lamps are strong in yellows, oranges and reds, warm colors; but not ingreens, blues and violets, cool colors.

ncandescent lamps are strong in yellows,oranges and reds, warm colors; but not ingreens, blues and violets, cool colors

Feeders are a set of conductors that carry a large amount of power from the _________ equipment toasecond panelboard called a _________________ from which the branch circuits may originate. Feedersmust be designed to provide sufficient power to all the branch circuits they supply, so the feederconductor should be capable of carrying the amount of current required by the ______, plus room for________ expansion

serviceequipment to a second panelboard called asubpanelboard from which the branchcircuits may originate.Feeders must be designed to provide sufficientpower to all the branch circuits they supply,so the feeder conductor should be capableof carrying the amount of current required bythe load, plus room for future expansion.

A bus or busbar is the other form of conductor and are solid bars used for _________ _____________in panelboards, switchboards or high ________ power distribution systems. Busbars are flat solid stripsor hollow tubes because their shape dissipates heat more efficiently. Solid strips are used for high currentapplications because of the heating effect of the resistance. Hollow tubes work because of the "skineffect" which means that electrons flow more easily near the surface of a conductor. Waveguide is a typeof conductor that is used at microwave RF frequencies (over 5 Ghz). At such high frequencies theelectrons travel right at the surface of the conductor. There is minimal current so it doesn't need to bevery thick.

solid bars used forpower distribution in panelboards,switchboards or high current powerdistribution systems.

Wire is by far the most common conductor in building electrical systems. Wire is sized with _____systems:

two