Test 3 Flashcards
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
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.
Exterior connectors used on conduit must be:
A. waterproof B. water-resistant C. either water-resistant or waterproof D. galvanized
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.
Which of the following substances is now regulated by Title 8?
A. concrete B. asbestos C. plaster board D. electric wire
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.
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'
D. 15’
At least 15’ clearance is required for service drops from 300 V to 600 V.
Who schedules the next phase of work after the rough wiring is done?
A. city inspector B. architect C. owner D. prime contractor
D. prime contractor
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
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.
Type MC cable may have what type of conductors?
A. copper B. aluminum C. copper-clad aluminum D. any of the above
D. any of the above
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
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.
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
C. the authority having jurisdiction
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
C. all devices must be approved by the authority having jurisdiction, or listed for use with the panel
NFPA = National Fire Protection Association
In fire alarm systems, the wire coming from the alarms must be:
A. mechanically supervised B. electronically supervised C. manually supervised D. unsupervised
B. electronically supervised
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
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.”
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. 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.
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"
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.
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
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.
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
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.
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
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.
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
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.
What is the maximum distance that outlets must be spaced for kitchen countertops?
A. 12" B. 24" C. 36" D. 48"
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.
What is the maximum rating for a garbage disposal on a 20-amp branch circuit?
A. 50% B. 70% C. 80% D. 90%
A. 50%
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'
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.
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
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.
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
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.
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
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.
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.
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.
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.
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.
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.
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.
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
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.
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.
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.
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.
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.
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”.
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.
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.
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
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
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.
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.
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.
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.
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.
