Test 3 Flashcards
0
Q
While the driver of a tandem-axle truck is backing up at a construction site, he or she should:
A. shout while backing up B. wave his or her hands and shout while backing up C. sound the backup warning device while backing up D. sound the horn while backing up
A
C. sound the backup warning device while backing up
All vehicles with a cargo capacity of 2.5 cubic yards or more are required to have a working automatic backup warning device. A “tandem-axle” truck would most likely be at least that large.
1
Q
Exterior connectors used on conduit must be:
A. waterproof B. water-resistant C. either water-resistant or waterproof D. galvanized
A
C. either water-resistant or waterproof
Connectors suitable for outside installations are not all waterproof, and if well sheltered they might not even need to be water-resistant. Connectors are selected based on their UL listing for a specific purpose. Usually, outside connectors should be raintight, but if the installation is below grade or subject to immersion, this is not enough. The water resistance of a connector also depends on proper installation. Plastic or aluminum connectors are not galvanized.
2
Q
Which of the following substances is now regulated by Title 8?
A. concrete B. asbestos C. plaster board D. electric wire
A
B. asbestos
The California Code of Regulations is broken up into 28 different Titles. Title 8 covers Industrial Relations and includes the Construction Safety Orders and General Industry Safety Orders, both of which have big sections detailing the many regulations on asbestos in the workplace.
3
Q
What is the minimum clearance above grade, as specified in the Electrical Code, for a service drop up to 600 volts?
A. 8' B. 10' C. 12' D. 15'
A
D. 15’
At least 15’ clearance is required for service drops from 300 V to 600 V.
4
Q
Who schedules the next phase of work after the rough wiring is done?
A. city inspector B. architect C. owner D. prime contractor
A
D. prime contractor
5
Q
When installing multiple fire detectors, it is a good practice to wire the detectors:
A. in series B. in parallel C. individually, with batteries D. in series and parallel
A
B. in parallel
Both series and parallel circuits are used, but the series fire alarm circuits are approved only for coded systems. In residential fire warning equipment, detectors must be wired in parallel as normally open elements that close (short) when activated. This prevents activating the alarm signal if there is a breach (open circuit) in the system wiring. A system integrity monitoring circuit is wired in series with the system wires to provide a trouble signal. Battery detectors are used only in existing construction.
6
Q
Type MC cable may have what type of conductors?
A. copper B. aluminum C. copper-clad aluminum D. any of the above
A
D. any of the above
7
Q
If you are installing several smoke detectors, you would:
A. wire them in series B. wire them in parallel C. use batteries D. use detectors listed for use with the control panel
A
D. use detectors listed for use with the control panel
All detectors must be listed for use with the panel. Both series and parallel circuits are used, with restrictions on the use of series circuits.
8
Q
If a fire detection sensor is to be wired to a control panel, it must be approved by:
A. the fire department B. the manufacturer's specifications C. the authority having jurisdiction D. the NEC
A
C. the authority having jurisdiction
9
Q
According to NFPA standards, when installing a fire-alarm panel and other devices attached to the panel:
A. all components must be purchased at the same time B. all devices being attached must be UL-approved for the panel C. all devices must be approved by the authority having jurisdiction, or listed for use with the panel D. any device that is equivalent to a listed device may be used
A
C. all devices must be approved by the authority having jurisdiction, or listed for use with the panel
NFPA = National Fire Protection Association
10
Q
In fire alarm systems, the wire coming from the alarms must be:
A. mechanically supervised B. electronically supervised C. manually supervised D. unsupervised
A
B. electronically supervised
11
Q
Where would you place smoke detectors in a family living unit to meet minimum code requirements?
A. crawl spaces B. kitchen C. every sleeping area and common hallway D. all of the above
A
C. every sleeping area and common hallway
Smoke detectors are required: (1) outside of each separate sleeping area, (2) in the basement, (3) in an attic, if finished, (4) in a common hallway, and (5) on each additional story if not already covered by (1), (2), (3), and (4). A separate sleeping area is defined as one or more bedrooms that are separated from any other bedrooms by a different type of room (such as a living room). Additional detectors in other locations are “recommended.”
12
Q
A GFCI is intended to:
A. protect people by de-energizing the circuit when the device's rated sense threshold is exceeded B. disconnect the circuit automatically when a pre-determined over-current is detected C. ensure electrical ground continuity D. ensure the integrity of electrical insulation
A
A. protect people by de-energizing the circuit when the device’s rated sense threshold is exceeded
A GFCI (Ground-Fault Circuit Interrupter) detects outgoing current that fails to return through the circuit neutral, indicating leakage to ground via any of many possible paths. When a leak is detected, the circuit is interrupted.
13
Q
If you use an extension ladder to reach a landing on the 2nd floor, how far must the ladder extend above the landing?
A. 12" B. 24" C. 32" D. 36"
A
D. 36”
The 36” is intended to provide a hand-hold for someone climbing the ladder. This applies to all similar situations, such as using a ladder to access a roof.
14
Q
Why is a conduit bender the best tool for bending EMT?
A. it produces a perfect bend B. it is easier to pull than a hickey C. it keeps the interior volume of the pipe unchanged D. it is most portable
A
C. it keeps the interior volume of the pipe unchanged
The Electrical Code requires that bends in either Electrical Metallic Tubing (EMT) or Rigid Metallic Conduit (RMC) be made by a means that does not damage the tubing or effectively reduce its internal diameter. EMT is too thin to bend with a hickey, which would kink the tubing, but a conduit bender makes a smooth bend in either EMT or RMC.
15
Q
A building has a 120/208 V wiring system and requires a 400-amp service. A 480 V power line is available. What size and type of transformer is needed?
A. 480 V, 400-amp in, 1.73:1 delta-wye with 120 V center taps B. 480 V, 100 amp in, 1:4 delta with neutral leg C. 832Y/480 V, 100-amp in, wye-connected 4:1 step-down D. 480/208 V, 400-amp in, 120 T-tap delta step-down
A
C. 832Y/480 V, 100-amp in, wye-connected 4:1 step-down
The building has a 3-phase 120/208 volt 4-wire wiring system, also called a “208Y/120.” This is obtained by using a 832Y/480 primary to 208Y/120 secondary 4:1 step-down transformer. When you step down the voltage 4:1, you step up the current 1:4, from 100 amps to 400 amps.
16
Q
What ohmmeter reading might indicate a good capacitor?
A. a high resistance reading, like an open circuit B. initial high reading followed by a low reading C. initial low reading dropping to a high reading D. you can only test a capacitor with a capacitance meter
A
C. initial low reading dropping to a high reading
An ohmmeter connected across a good capacitor should jump toward a zero reading, then fall back toward an infinity reading (open circuit) as it charges.
17
Q
At least two 20-amp circuits must be provided in the kitchen for small appliance receptacles, but one of these circuits may be extended to receptacles in a:
A. bedroom B. family room C. bathroom D. dining room
A
D. dining room
Bathrooms must have a separate 20-amp circuit. The two or more small-appliance circuits for the kitchen may also supply outlets for refrigeration and pantry areas, breakfast rooms, dining rooms, and similar areas.
18
Q
What is the maximum distance that outlets must be spaced for kitchen countertops?
A. 12" B. 24" C. 36" D. 48"
A
D. 48”
No point on a wall may be more than 24” from an outlet. This will be satisfied if the outlets are no more than 48” apart.
19
Q
What is the maximum rating for a garbage disposal on a 20-amp branch circuit?
A. 50% B. 70% C. 80% D. 90%
A
A. 50%
20
Q
What is the maximum length of a power cord for a self-contained spa when it is protected by a GFCI?
A. 5' B. 6' C. 10' D. 15'
A
D. 15’
As defined in the Electrical Code, a self-contained spa has a built-in power panel. A cord of up to 15 feet may be used only if protected by a GFCI. If liquidtight flexible conduit is used, it is limited to 6 feet.
21
Q
A transformer that provides a 120/240 V service entrance must be grounded:
A. at the low leg of the primary B. at the high leg of the primary C. anywhere on the secondary D. at the center tap of the secondary
A
D. at the center tap of the secondary
The center tap is the neutral in this system, also called the grounded circuit conductor. Grounding the center tap minimizes the hot-to-ground voltage to 120 volts. In a typical residential installation, grounding electrodes are installed to establish this connection to earth both at the service-pole-mounted transformer and within 5 feet of the service panel. The first is installed by the electric company and the second by the residential electrician.
22
Q
Where would a 208Y/120 V service most likely be installed?
A. single family residence B. light industrial building C. heavy industrial building D. special purpose only
A
B. light industrial building
A grounding electrode system is the last step in contact with the earth. According to the current code, a gas line may not be used as a grounding electrode. If one is present, a metal water pipe MUST be connected as a grounding electrode, but it cannot be used as the only electrode in the system. A copper ground rod, a 10’ section of empty steel pipe, or a connection to steel reinforcing bar in a slab foundation may each be used as additional electrodes. Connections 5 & 6 are part of the equipment grounding system, not the grounding electrode system.
23
Q
The secondary of a transformer provides 240∆/120 V power in an older factory service drop. Where must this transformer be grounded?
A. at the A-phase terminal B. at any phase terminal C. on the winding that provides the two 120 V legs D. it should not be grounded
A
C. on the winding that provides the two 120 V legs
This older delta system provides power for three-phase motors and a limited number of lighting and general use circuits. If a phase terminal (a corner of the “delta”) were grounded, this would limit the hot-to-ground to 240 V. But grounding the center tap in the one winding that provides 120 V has the effect of limiting the hazard to 208 V.
24
You would ground a transformer for a 480Y/277 V service at:
A. the common connection between the 3-phase windings
B. one corner of the "wye"
C. one corner of the "delta"
D. the center tap that provides the neutral
A. the common connection between the 3-phase windings
This transformer provides 480 V three-phase power for heavy motors and 277 V single-phase power for industrial lighting. This can be achieved by connecting the secondaries of three single-phase transformers in a "wye" configuration with a common connection providing the neutral for the single phase lighting circuits and the phase connections providing the three-phase motor power. Grounding the neutral limits the hot-to-earth to 277 V.
25
An electrician hired to upgrade a service from 100 to 200 amps must:
A. obtain a permit before running the new drop
B. consult with an engineer
C. notify the utility company first
D. let the utility company run the wire
D. let the utility company run the wire
The utility company has to plan any changes to their power lines and has special training and equipment for working on the high voltage end of the drop. As with the telephone company, no one else is allowed to tamper with their equipment. After you install an approved panel, they will bring the power drop to you.
26
Where must bonding jumpers be installed?
A. around water meters or unions in water pipes
B. around gas meters
C. from gas lines on the house side of the meter to water pipes
D. between hot and cold pipes going to a water heater
B. around gas meters
The gas pipes inside a building must be bonded to the grounding system in the building to reduce the shock hazard should a wire come into contact with the gas pipe. The gas pipes might also be isolated electrically from the underground portion by an insulating bushing.
27
Which metal objects must be bonded near a pool or spa?
A. ladders
B. light housings
C. base of diving board
D. all of the above
D. all of the above
All metal objects within 5 feet of the pool or spa must be bonded to the grounding system unless they are separated by a non-conducting fence or other effective barrier.
28
Which should you not use for motor overload protection?
A. single-element fuse
B. dual-element fuse
C. thermal relay
D. magnetic relay
A. single-element fuse
Motor overload protection must sense excess current and distinguish it from normal temporary starting currents. Dual element (time delay) fuses will do this, but single element fuses cannot.
29
All of the following might be an acceptable controller for a 1/2 HP motor except:
A. attachment plug and receptacle
B. heavy-duty snap switch
C. manual starter
D. magnetic starter
A. attachment plug and receptacle
The Electrical Code does not allow a plug and cord to be the only control for motors larger than 1/2HP.
30
Which rating system is not used to identify the correct size starter for a motor?
A. UL rating
B. NEMA number system
C. integral horsepower
D. letter rating
A. UL rating
31
Which of the following arrangements is not a correct sequence when going from Phase-A to Phase-B to Phase-C in a panel?
A. LEFT → RIGHT
B. BACK → FRONT
C. TOP → BOTTOM
D. BLACK → RED → BLUE
B. BACK → FRONT
Busbars in a panel should go from Phase-A in front to phase-C in back. The color code given in "D" is typical but not required.
32
When a fused main is installed in a service panel having breaker branches, all of the following are true except:
A. breakers must interrupt more than 10,000 amps
B. fuses must be current limiting
C. fuses must be listed for use as service equipment
D. panel is listed as "series rated"
A. breakers must interrupt more than 10,000 amps
In a series rated panel, the branch breakers depend on the main breakers or fuses to limit overload or fault currents to within the interrupt rating of the branch breakers, which is typically 10,000 amps. The use of current-limiting fuses for mains reduces overcurrents to what the branch breakers can handle. In a fully rated panel, the branch circuit protection must have interrupt ratings of 20,800 amps or more (which is close to the service main rating) in order to handle expected overcurrents without any help from the mains.
33
What is meant by a "selective system" in a panelboard?
A. the breakers detect only certain types of faults
B. a branch circuit fuse will trip before the main does
C. separate breakers are provided for many small circuits
D. separate fuses are provided for many small circuits
B. a branch circuit fuse will trip before the main does
When an overcurrent device trips in a selective system it isolates the overload or fault without disabling other circuits in the panel. Panels tend to be selective for low-level faults and non-selective for high-level faults.
34
A Type-S fuse adapter fits the same size socket as a(n):
A. Type-T fuse
B. Type-W fuse
C. Edison base plug fuse
D. all of the above
D. all of the above
Type-S fuse adapters all fit the same plug-fuse socket in the panel but will accept only the specific size fuse for which it is rated.
35
If a panel uses rejection fuseholders for the mains, you might have to install:
A. Class-R fuses
B. Class-H fuses
C. extra insulating barriers
D. a circuit breaker adapter
A. Class-R fuses
Rejection fuseholders accept only fuses above a given voltage/interrupt rating. Class-R fuses are designed to be mated with rejection fuseholders.
36
Class-T fuses are:
A. the same as Edison base fuses
B. time-delay fuses
C. compact, fast acting, and high interrupt rating
D. not suitable for mains
C. compact, fast acting, and high interrupt rating
Class-T fuses are a type of cartridge fuse that comes in different physical sizes with different ratings. They are generally high performance and fast-acting. They are also current-limiting, so they can be used as mains in series rated panels with 10,000-amp interrupting capacity branch circuit breakers. Be careful not to confuse "Class-T" with "Type-T".
37
When troubleshooting a living room circuit, you observe that one light will not go on but another is brighter than normal. What might be the problem?
A. a short
B. an open hot wire
C. an open neutral
D. high ground resistance at panel
A. a short
Possible scenario: In a 3-wire circuit, a hot wire from the non-working circuit has come loose from an untightened terminal in the light fixture, thus disconnecting the voltage to that light. The loose wire is also shorted to (touching) the neutral terminal. In addition, the neutral is poorly grounded at the panel or has a weak connection somewhere in the circuit. This causes an increase in the voltage between the neutral and the working circuit, causing that light to glow brighter. None of the answers are right on target, but "a short" seems closest to an accurate description.
38
A toaster that is running on a kitchen circuit becomes overheated. What problem should you look for?
A. a short in the appliance
B. an open neutral
C. ground and hot reversed
D. ground and neutral reversed
A. a short in the appliance
If the heater coils are shorted midway they can run hotter than normal without tripping the 20-amp breaker.
39
The controller for a motor on a separate circuit has a much louder AC hum than controllers for similar motors in the same room. Which would not be a cause of this extra noise?
A. lower than normal voltage
B. higher than normal voltage
C. dirt or misalignment preventing armature from seating
D. replacement coil is the wrong specification
B. higher than normal voltage
40
When an appliance that is connected to a particular circuit comes on, the lights dim. When it goes off, the lights become bright again. What is the problem?
A. overloaded circuit wires
B. too low a rating for the fuses
C. fluorescent lights where incandescent should have been used
D. poor neutral connection in split-wired circuit
A. overloaded circuit wires
41
All circuits in a house are working except in one bedroom, where none of the lights or receptacles work. A neon test light indicates there is voltage between the line and ground screw. What is the problem?
A. tripped breaker
B. open circuit neutral
C. open service panel neutral
D. missing ground
B. open circuit neutral
A tripped breaker would result in no voltage at the receptacle. If the panel neutral were open the rest of the house would be dead too, and a missing ground would fail to complete the test circuit.
42
In which location is the use of a test meter with a CAT-II 600-volt safety rating strongly recommended?
A. low energy electronics in protected office equipment
B. outlets more than 10 meters (33 ft) from service panel
C. outlets 6 meters (20 ft) from service panel
D. main service panel
B. outlets more than 10 meters (33 ft) from service panel
The IEC (International Electrotechnical Commission) has defined four Overvoltage Installation Categories {or CAT I-IV) based on the capacity of wiring to carry surge currents ("spikes") that can result from events upstream. Since wire impedances limit surge currents, the danger progressively lessens as you move downstream from the large gage wires in powerlines toward the smaller gage branch wires. CAT-III locations are considered to have an impedance of 2 ohms, compared to 12 ohms for CAT-II, and 30 ohms for CAT-I.
Test meters are CAT rated to certify the level of surge they can handle without damage to the meter or hazard to the user. CAT-I meters offer the lowest level of protection, and their use is best restricted to low energy circuits inside surge-protected electronic equipment. A CAT-II location includes branch circuits more than 10 meters from a panel. CAT-III locations include work on distribution panels and on branch circuits within 10 meters of a panel.
43
What is the purpose of using a "three-point test" procedure when troubleshooting with a test light or meter?
A. to test watts by connecting current, voltage, and common
B. to gain more clues by measuring three different voltages
C. to detect an intermittent problem
D. safety
D. safety
In a three-point test you confirm that a meter (or test light) is working by testing it: (1) on a good circuit, (2) on the unknown circuit, and (3) on the good circuit again. This way you know for certain that the meter will not falsely indicate zero voltage where in fact power is present.
44
What is not true of electrical equipment rated for hazardous locations?
A. arcs or sparks are contained within a rated housing
B. conduit seals limit an explosion to near the source
C. only cool gases are allowed to escape from an electrical explosion and into the hazardous location
D. an explosion will not occur inside rated equipment
D. an explosion will not occur inside rated equipment
Electrical enclosures and equipment that are rated for hazardous locations do not actually prevent electrical explosions, sparking, or arcing. Instead, they prevent what happens inside the equipment from causing a fire or explosion in the surrounding air. Any heat generated inside the equipment is cooled and dissipated before the pressure is released to the environment as cooled gases.
45
Which answer describes a Class-I hazardous location?
A. potentially explosive gases, vapors, or liquids
B. conductive and/or explosive metal or carbon dusts
C. combustible or explosive plastic dust or flour
D. ignitable textile fibers or sawdust in a wood shop
A. potentially explosive gases, vapors, or liquids
Answers "B" and "C" are examples of a Class II hazardous location. Answer "D" is an example of a Class III hazardous location.
46
What is the difference between a Class-II, Division-1 location and a Class-II, Division-2 location?
A. one is a more immediate hazard than the other
B. one is a location with acetylene and the other is a location with hydrogen gas
C. one is a location with metal dust and the other is a location with carbon dust
D. Division-1 is a less severe hazard than Division-2
A. one is a more immediate hazard than the other
Division 1 represents an immediate hazard, in this case ignitable concentrations of airborne dust. Division 2 represents a potential hazard, such as settled dust layers that might short out equipment or become explosive when disturbed.
47
How far from a door may the nearest receptacle be located on an interior wall?
A. 4'
B. 6'
C. 8'
D. 10'
B. 6'
Every wall space of at least 2 ft should be within 6 ft horizontally of a receptacle. This means a receptacle can be 6 ft from the doorframe, but if the wall space is less than 6 ft wide, it would have to be closer.
48
A lighting circuit has two three-way switches in the black line and you are asked to add another switch. Into which circuit leg would you tap a four-way switch?
A. red
B. black
C. white
D. green
B. black
Read the question carefully. What the question is saying is that the three-way switches serve to interrupt the black line. The white return wire should be marked with black marking tape. Since the four-way switch must be inserted between the two three-way switches, it also interrupts the black leg of the circuit.
49
One wall of a living room is 20' long and finished entirely in glass panels. The specifications call for three receptacles along this wall. What should you do?
A. use floor receptacles
B. eliminate the receptacles
C. install two receptacles at the corners of adjacent walls and eliminate the third one
D. ask the general contractor to get the specs changed
A. use floor receptacles
Three receptacles are one more than is required by the Electrical Code for a 20' wall, but you should follow the specs as long as they at least meet the minimum codes. The Electrical Code allows floor receptacles to replace required wall outlets, but only if they are within 18" of the wall.
50
The allowed wire fill in a raceway is usually:
A. 20%
B. 40%
C. 75%
D. 90%
B. 40%
In most circumstances raceways hold more than two conductors, and the allowable fill area for more than two conductors is 40%.
51
When a gutter is used as a raceway, what is the maximum wire fill allowed throughout its length?
A. 60 wires
B. 30 wires
C. 40%
D. 75%
B. 30 wires
The allowable wire fill is the same for both gutters and wireways: a maximum of 30 wires (except in theaters & elevators). Based on cross-sectional areas, the maximum fill is 20% for wires running through and 75% only at the points where splices and taps are made.
52
The maximum wire fill allowed in the side-gutter or wiring space contained inside a load center, meter, or other enclosure is:
A. 20%
B. 30%
C. 40%
D. 75%
C. 40%
A "side gutter" is an interior wiring space in an enclosure.
53
The maximum wire fill permitted at all points in an auxiliary gutter is:
A. 20%
B. 30%
C. 40%
D. 75%
A. 20%
An auxiliary gutter is a trough separate from the enclosure it is associated with.
54
The maximum wire fill allowed in a nipple is usually:
A. 20%
B. 60%
C. 75%
D. 90%
B. 60%
A nipple extends a maximum of 24" to connect two boxes or enclosures. It may have greater wire fill than a raceway.
55
The allowed wire fill in a wireway is usually:
A. 20%
B. 40%
C. 60%
D. 75%
A. 20%
56
Which type of conduit would be best between a building and parking lot lights?
A. Romex
B. electrometallic tubing
C. intermediate metal conduit
D. rigid metal conduit
D. rigid metal conduit
Romex (type NM) is not approved for burial, EMT is not recommended, and IMC is less durable than rigid conduit. Rigid non-metallic conduit (PVC) may also be used. All methods require at least 24" burial under a parking lot or road.
57
In a bearing wall, a hole bored through a wood stud or top plate may have diameter of up to _____ of the beam width without first being detailed in the plans.
A. 25%
B. 30%
C. 40%
D. 50%
B. 30%
The Building Code allows up to 1/3 or 33% (the best answer offered is 30%). If larger holes are needed, they must be detailed in the plans and approved before installation.
58
When you drill through a wood joist, the hole may be no closer than _____ to the edge.
A. 1"
B. 1-1/4"
C. 1-1/2"
D. 2"
D. 2"
Compare this to 1-1/4" for bearing wall studs. Some requirements are different for joists than for studs because of larger bending forces. Like holes in studs, the diameter must also be no more than ⅓ the width of the joist.
59
What percentage of a bearing stud's width may be notched?
A. 0%
B. 10%
C. 17%
D. 25%
D. 25%
60
What percentage of a wood joist's depth may be notched at the top or the bottom?
A. 10%
B. 17%
C. 25%
D. 33%
B. 17%
17% is an odd percentage, but it represents the code limit of 1/6 (16.67%) of the depth of the framing member. Notches of any depth are not allowed in the middle one third of a span.
61
To penetrate a masonry wall in an old home you would use a:
A. ram jet
B. hole saw
C. stucco bit
D. core drill
D. core drill
The basic tools for drilling masonry and concrete are a masonry bit, which has carbide cutting edges, and a core drill, which has carbide or diamond cutting edges. Another way to drill is with a with a hammer and star drill. We are not aware of a special bit for stucco.
62
How much current does the neutral carry in a 208-V panel?
A. the same as the hot wires
B. 54% of the phase current
C. only the unbalanced load
D. none
C. only the unbalanced load
Since this is a three-phase Y-connected system, the neutral carries the unbalanced load from the three-phase wires.
63
What size service is needed for a family residence with 5000 square feet of living area and all electric appliances?
A. 100 amps
B. 200 amps
C. 300 amps
D. 400 amps
B. 200 amps
We calculated a minimum of 200 amps for the service based on a formula and sample calculation in the Electrical Code. The heating load would depend on climate and construction. The main components of the calculation follow (note that 1 kVA = 1000 VA):
```
CIRCUITS LOAD (VA)
General lighting: 5000 sq ft x 3 VA = 15,000
Small appliance: 3 x 1500 VA = 4,500
Required laundry: 1,500
Range: 8,000
Clothes dryer: 5,000
Washing machine: 1,500
Dishwasher: 1,000
Garbage disposal: 800
Attic fan: 700
Bath light/fan/heat units: 2 x 1,500 = 3,000
Garage door opener: 800
Water heater: 4,000
```
```
GENERAL LOAD TOTAL:
21,000 + 24,800 = 45,800 VA
First 10 kVA at 100%: 10,000
Balance at 40%: (45.8k - 10.0k) x 0.40 = 18,320 VA
TOTAL: 28,320 VA EST.
```
ELECTRIC HEATING LOAD
Furnace: 5000 sq ft x 8 VA = 40,000 VA
Demand factor: 40% x 40.0 kVA = 16,000 VA
TOTAL CALCULATED LOAD = 28,320 VA + 16,000 VA = 44,320 VA
CALCULATED AMPERAGE = 44,320 VA ÷ 240 V = 184.67
Round up to a common service size of 200 amps. As you can see, over half of the load is contributed by the electric furnace, water heater, and clothes dryer. The other factor that makes this house different is the large floor area.
64
More than one service entrance may be supplied from a single service drop in each of the following cases except:
A. multiple occupancy building (residential or commercial)
B. common area circuits in a duplex
C. up to 6 service disconnects grouped in one location
D. a single-family residence and 2 guest cottages
D. a single-family residence and 2 guest cottages
The Electrical Code allows one extra building associated with a single family dwelling to be supplied by the same service drop, not two extra buildings.
65
What section of the Electrical Code covers wire sizes?
A. 100
B. 310
C. 500
D. 680
B. 310
66
When may a basement be counted as a story in calculating living space floor area in a residence?
A. when local codes permit
B. when the ceiling is at least 7-1/2 feet high
C. when the basement is finished
D. never
C. when the basement is finished
67
At an excavation, an Underground Service Alert (U.S.A.) marking on the dirt with red paint or chalk indicates:
A. gas lines
B. water lines
C. telephone lines
D. electric power lines
D. electric power lines
Yellow = gas, other chemicals, or steam; blue = water; orange = telephone/CATV; red = electric; green = sewer or storm drain; white = outline of proposed excavation.
68
Which colors are used to mark a 208-V branch circuit?
A. black, red, and white
B. black and blue
C. red and gray
D. orange and red
B. black and blue
208 V is normally found only as a phase-to-phase voltage from three-phase supplies, so the neutral is not used in the 208-V branch circuits from those supplies. The most common phase colors for any voltage are black, red, and blue. Using only two-phase wires supplies a single-phase 208-V load. Answers "A" & "C" are eliminated because they include a neutral. "D" would be a 240-volt circuit between phases of a 240/120 high leg panel.
69
A bonding jumper connected to a dryer chassis for a ground must be at least:
A. No. 12
B. No. 10
C. No. 8
D. No. 6
B. No. 10
This connects the neutral to the chassis. It must only be connected if a three-pole three-wire cord is installed to connect the appliance to the three-prong receptacle seen in the pre-existing wiring of older buildings. New building wiring must provide a three-pole four-wire receptacle with separate ground. A four-wire cord is then used, and the ground and chassis must not be connected to the neutral.
70
How many continuous watts of load are permitted in a 12-gage branch circuit?
A. 1500
B. 2000
C. 2500
D. 3000
B. 2000
The required overload protection for No. 12 AWG wire is 20 amps, and the permissible load of a branch circuit is 80% of the overload protection rating.
0.80 x 20 amp = 16 amp
16 amp x 125 volts = 2000 volt-amps
A volt amp (VA) is equivalent to a watt.
71
If a three-phase motor is running backwards, what can you do?
A. remove and reverse the rotor
B. reverse any two phase wires
C. send it back to the manufacturer
D. reverse the starter winding
B. reverse any two phase wires
The direction is determined by the phase direction, so swapping any two phase wires will reverse the rotation.
72
The wire size for a feeder supplying two or more continuous duty motors is based on ____ of the full load current of the largest motor plus ____ of that for all other motors.
A. 125% .... 100%
B. 125% .... 85%
C. 110% .... 100%
D. 175% .... 85%
A. 125% .... 100%
73
When installing grounds at a generator supplying power to a building with a metal roof and metal siding, what should the siding be grounded to?
A. generator frame
B. bond to the neutral bus in main distribution panel
C. grounding electrode conductor
D. equipment grounding conductor
D. equipment grounding conductor
74
Whom would you call for temporary power after a facility is wired?
A. the CSLB
B. local OSHA
C. the City Building Department
D. the power company
D. the power company
Only the power company makes power drop connections to their lines.
75
You have a three-phase motor with nine leads. How are the connections made?
A. phase I to 1,2,3; phase II to 4,5,6; phase III to 7,8,9
B. phase I to 1,7; phase II to 2,8; phase III to 3,9; wire 4,5,6 together
C. phase I to 1,2,3,4,5; phase II to 6,7; phase III to 8,9
D. phase I to 1,2,3,4,5; phase II to 6,7,8,9; phase III not connected
B. phase I to 1,7; phase II to 2,8; phase III to 3,9; wire 4,5,6 together
76
What is the ampere rating of a 75 kVA, 480 V, three-phase transformer?
A. 50 amps
B. 75 amps
C. 90 amps
D. 100 amps
C. 90 amps
With three-phase circuits, you still use Watt's Law (I = P ÷ E), but you multiply the voltage by 1.73 (the square root of 3):
```
I = P ÷ (E x 1.73)
I = 75,000 ÷ (480 x 1.73) I = 90 amps
```
77
What type of material may not be used in a seven-story office building?
A. non-metallic sheathed cable
B. flexible metal conduit
C. flexible metal tube
D. BX
A. non-metallic sheathed cable
You may not use type NM, NMC, or NMS in any building taller than three stories.
78
Double-cleat ladders may not be longer than:
A. 10'
B. 12'
C. 24'
D. 30'
C. 24'
Double-cleat ladders look like two ladders connected side-by-side. They are required for two-way traffic or when used by 25 or more employees.
79
You must design a 120/208-volt system for small appliances, lights, etc. What type of transformers would you use?
A. delta - delta
B. wye - delta
C. delta - wye
D. wye - wye
D. wye - wye
80
Which of the following would be considered good practice when working with energized equipment?
A. use a fault detector
B. remove jewelry
C. ground yourself
D. keep one hand in your pocket
D. keep one hand in your pocket
It may sound odd, but the theory is sound and could save your life. If you're working with both hands on an energized circuit and make a mistake, current could run up one arm and down the other -- crossing through your chest and possibly stopping your heart. If one hand is in your pocket, the current will more likely run down your side to the ground, giving you a burn but not crossing through any vital organs.
81
How many receptacles would be in a 2-gang box?
A. 1
B. 2
C. 3
D. 4
B. 2
82
What would you need if you wanted a single light fixture to be controlled by two different switches?
A. two-way switches
B. three-way switches
C. single phase switches
D. three-phase switches
B. three-way switches
83
Electrical conduits on gasoline islands must be sealed to a minimum height of:
A. 18"
B. 24"
C. 36"
D. 48"
D. 48"
This is only in the "immediate vicinity" of the island. However, within 20' of the island, conduits must still be sealed to a height of 18".
84
What is the minimum depth of clear working space for equipment up to 600 volts?
A. 30"
B. 36"
C. 48"
D. 72"
B. 36"
Equipment up to 600 volts is not considered "high voltage." The minimum depth of clear working space varies with the specific conditions: If there is live, exposed, and ungrounded equipment on either side of an operator, the minimum depth of clear working space increases to 48".
85
The owner of a house built between 1965 and 1972 tells you that a receptacle glowed bright orange, then quit working. Which of the following is a likely cause?
A. aluminum wires in a copper-rated receptacle
B. copper wires in an copper-rated receptacle
C. zinc wires in a copper-rated receptacle
D. magnesium wires in a copper-rated receptacle
A. aluminum wires in a copper-rated receptacle
Aluminum wires are less conductive than copper, and many fires have started because they are connected to devices that were designed for use with copper. Although still allowed by code (if used with properly designed equipment), they are no longer recommended.
86
What is the maximum height of a ladder-jack scaffold?
A. 6'
B. 10'
C. 12'
D. 16'
D. 16'
87
Why would you use a dry transformer?
A. to increase potential
B. to decrease potential
C. to increase current
D. to decrease current
B. to decrease potential
In this case "potential" is just another way of saying "voltage." The answer would be the same whether you use a dry or oil-filled transformer.
88
What is the minimum height for outlets in a shop with hazardous materials?
A. 12"
B. 15"
C. 18"
D. 24"
C. 18"
It depends on exactly what the "hazardous materials" are. For most repair garages (our interpretation of "shop"), the primary dangers are flammable liquids and fumes. In these situations, outlets must be at least 18" above the floor.
89
In an office with 120 40-watt fluorescent bulbs, how many 120-volt, 20-amp lighting circuits would you need?
A. 1
B. 2
C. 3
D. 4
B. 2
To calculate the number of branch circuits, use the following formula:
number of circuits = total load ÷ capacity of each circuit
number of circuits = (120 x 40 W) ÷ (120 V x 20 A) = 2
90
If the current drops, what would you do?
A. increase pipe size
B. increase wire size
C. decrease wire size
D. decrease pipe size
B. increase wire size
91
In a school, twenty 75-watt incandescent lights were replaced with twenty 20-watt fluorescent bulbs. If they pay $0.10/KWH, how much will they save in a year?
A. $100
B. $275
C. $375
D. $475
B. $275
For our calculations, we're assuming the lights are on for 10 hours a day, 5 days a week, 50 weeks a year. (The State might give you different numbers than this.)
Incandescent bulbs:
(20 bulbs x 75 watts) = 1500 watts
(10 hours x 5 days x 50 weeks) = 2500 hours per year
(1500 W x 2500 hrs) ÷ 1000 = 3750 kWH/yr
3750 kWH x $0.10/kWH = $375/yr
Fluorescent bulbs:
(20 bulbs x 20 watts) = 400 watts
(400 W x 2500 hrs) ÷ 1000 = 1000 kWH/yr
1000 kWH x $0.10/kWH = $100/yr
$375 - $100 = $275 per year.
92
What is the maximum height for an office light switch?
A. 24"
B. 36"
C. 48"
D. 60"
C. 48"
93
One 75-watt incandescent bulb is replaced with a 20-watt fluorescent bulb. If the customer is paying $0.45/KWH, how much do they pay per day using the fluorescent bulbs?
A. $0.20
B. $0.22
C. $0.45
D. $0.75
B. $0.22
We're assuming "day" means 24 hours. Also, notice the question asks "pay" not "save."
(20 W x 24 hrs) ÷ 1000 = 0.48 kWH;
0.48 kWH x $0.45 = $0.22.
94
What is the minimum horizontal distance between electrical outlets mounted on opposite sides of a fire wall?
A. 0"
B. 12"
C. 18"
D. 24"
D. 24"
95
A receptacle in a kitchen should have a GFCI:
A. if within 6' of the sink
B. if within 3' of the sink
C. if within 2' of the sink
D. regardless of location
A. if within 6' of the sink
96
An incandescent light is supposed to be controlled by two switches. One switch can turn the light on and off, but the other switch does nothing. The owner says it has been this way since the house was built. What could be the problem?
A. reversed neutral and grounded conductors
B. reversed hot and traveler conductors
C. reversed hot and grounded conductors
D. reversed cold and hot wires
B. reversed hot and traveler conductors
97
When deciding where to locate an electric meter:
A. check with the owner
B. check with the local building department
C. check with the local utility company
D. check with the CSLB
C. check with the local utility company
98
What size conduit should be used for 4/0 service-entrance conductors?
A. 1.25"
B. 1.5"
C. 2"
D. 3"
C. 2"
99
What is a conduit termination called?
A. dead end
B. dead front
C. dead after
D. dead before
A. dead end
100
What do you do first to confirm the repair of a system?
A. power up and load the system
B. reset the breaker and check for voltage
C. with the breaker off, use an ohmmeter to test for shorts
D. use an ammeter to test for shorts
C. with the breaker off, use an ohmmeter to test for shorts
The next thing you should do is power up and load the system to check each fixture and outlet.
101
At what DC voltage should you set a Megger when testing the insulation of a wire?
A. the same DC voltage as the circuit voltage
B. a slightly lower DC voltage than the normal peak AC voltage
C. the same DC voltage as the voltage rating of the insulation
D. a slightly higher DC voltage than the AC peak voltage.
D. a slightly higher DC voltage than the AC peak voltage.
A Megger uses DC voltages and should be set a little higher than the peak voltage of the rated AC voltage of the circuit under test. This will reveal borderline weaknesses in insulation that could affect circuit integrity.
102
Where may you not use PVC conduit?
A. embedded in concrete
B. in a Class I hazard area
C. buried in soil
D. in wet locations
B. in a Class I hazard area
103
What size pull box is needed for 4" PVC?
A. 18"
B. 24"
C. 32"
D. 36"
C. 32"
The length of a box for straight pulls must be at least 8 times the size of the largest conduit entering the box.
4" x 8 = 32"
104
What type of light can be mounted on the wall in a closet?
A. ceramic keyless
B. fluorescent
C. open incandescent
D. partly closed incandescent
B. fluorescent
105
What type of conduit is used in a Class I hazard area?
A. rigid metal
B. metallic flexible
C. PVC
D. EMT
A. rigid metal
106
An electrician has to run wires through a cold box to get to the outside. What should be used on the raceway to keep the air from the lines?
A. duct seal
B. pressure fittings
C. seal-off fittings
D. electrical tape
C. seal-off fittings
107
Where would you not use nonmetallic sheathed cable?
A. strip mall
B. two-story apartment
C. house remodel
D. five-story condo
D. five-story condo
108
Sheetmetal raceways must be secured every ___ along their entire length.
A. 3'
B. 4'
C. 5'
D. 6'
C. 5'
109
An ohmmeter pegs out when you hook up the leads. What does this indicate?
A. short
B. open circuit
C. closed circuit
D. capacitor is OK
C. closed circuit
A short would give the same reading, but "closed circuit" is a more general answer.
110
Where must the disconnect for a 460 V motor be located?
A. within sight of the motor
B. within 50 feet of the motor
C. on the controller
D. both A & B
D. both A & B
111
Which of the following may you use when installing a receptacle near a cleaning station using highly flammable chemicals?
A. PVC 40
B. EMT 10
C. intermediate metal conduit
D. NMC
C. intermediate metal conduit
112
According to the Energy Efficiency Standards, general lighting in a water closet must have an efficacy of at least how many lumens per watt?
A. 25
B. 30
C. 36
D. 40
D. 40
113
What type of conduit is used within 20' of a propane tank?
A. rigid metal
B. PVC
C. flexible metallic
D. EMT
A. rigid metal
This is another example of a Class I hazard.
114
What is the daily cost for a 600-watt appliance that runs 5 hours a day at $0.14 per kWh?
A. $0.48
B. $0.42
C. $0.70
D. $1.40
B. $0.42
600W ÷ 1000W/kW x 5 hr x $0.14/kWH = $0.42.
