229 Multiple choice questions
- Per NEC 250.116 ground rods should attach to metal fences
- Visible and within 50 ft.
- The current stays the same cause the doubling is offset by the halving.
- Two outside ground wire are needed on a 400 amp.
- "Authority Having Jurisdiction (AHJ)"
- active or live
- NEC Section 250.118(5)
- NEC 225.18
- A grounded conductor is a system or circuit that is intentionally grounded.
- False, demand factors of lighting does not apply to this table.
- The smallest grounding conductor permitted is 6 awg or larger.
- 1. The Builder
- 2 ground rods 6 ft apart.
Depending on the location and environment, 3ft. may be insufficient
clearance. While grouping apparatuses tightly may save space, repair and
maneuvering options are limited should a device fail.
- NEC 250.114
- Is dedicated to the sizes of the grounding conductor
- False, run ground wire from panel to copper water pipe then jump the water meter using grounding clamps.
- Isolated systems are used in healthcare facilities due to explosive gases.
maximum amount of electrical current a conductor or device can carry
before sustaining immediate or progressive deterioration.
- NEC Tables Annex C1 and C2 identify both wire sizing and the temperature a wire can handle in amps.
- Per NEC 230.10, vegetation is disallowed as a support device.
- True, Receptacles fed from subpanels must have their equipment grounding bar that is electrically isolated from the neutral bar.
- It guards wire against damage.
- Per NEC 225.14, separated by 4in.
permanent joining of metallic parts to form an electrically conductive
path that ensures electrical continuity and the capacity to conduct
safely any current likely to be imposed."
- A device designed to trip when an overcurrent is detected.
Arcing is the phenomenon in which electrons jump across insulators to
positive terminals, which can occur through air, paper, rubber, or any
- 48 in.
- 350MCM or 400MCM
- 16 in.
- Shows in two columns (milimeters and inches), how many wires in trade size you can place in a box.
- True, although there are exceptions.
- NEC Section 250-126
- NEC 310.8
- Air, does not conduct electricity.
- Covers the sizes of alternating current grounding electrode conductors.
- Voltage level, amount of protective clothing, and moisture on skin or outerwear all impact a ground connection.
- 2/0 or 4/0
- Identified as the "B" leg
- False, Per NEC 230.24, Service drop connectors shall not be readily accessible.
- NEC Article 358 covers EMT.
- True, One is required, Two are suggested.
- Is a measure of the amount of electric charge passing a point in an electric circuit per unit time.
- Electrical installations at permanently installed pools.
- False, Protecting a motor and a motor circuit are two very different things
- Safety is the most important aspect of an electrician's job.
- True, Per NEC 422.35
- True, motors convert electricity to rotational motion, while generators convert rotary motion to electricity.
- For a raceway to be used. Find a value for area larger than the raceway area calculated previously.
- The fill of metal boxes appears in NEC Tables 314.6 A and B.
- False, Per 360.12, FMT is disallowed from battery storage areas
- True, when those water pipes are grounded.
- True - NEMA is the acronym for National Electrical Manufacturers Association.
- 1.Insulated Housings.
2. Ground prong on plugs.
- people and property
to underground service, overhead electrical service is simpler to
troubleshoot and repair and is the easier option when running
electricity across roadways, waterways, and right-of-ways.
- False, The way to ground a transformer in a commercial building is to place a grounding rod outside or beneath the building.
- NEC 314.3
- True, An attic with a furnace requires a receptacle to honor safety and sound wiring requirements.
- Covers clearances on buildings.
- NEC 320
- 1. Listed Pressures Connectors
2. Terminal Bars
3. Pressure Connectors Listed As Ground and Bonding Equipment
4. Exothermic Welding
5. Machine screw-type fasteners that engage not less than two threads or are screwed with nuts
- Green finish
- According to the NEC, an outlet is defined as a point in a circuit at which current is taken.
- False, NEC 314.4, requires all metallic boxes to be grounded.
ohms law, the fuse value would be 10V/2ohms or 5 amperes. However, if
the voltage increased slightly and harmlessly, the fuse would blow.
Therefore the fuse should be based on the nature of the load.
- When only the steel is connected to earth ground.
- True, Per NEC 210.11
- True (NEC 250.92B)
- A grounding conductor is green.
- 30amps (10 x 3)
- True, Electricians may use rebar as a grounding means.
DC, electrons flow in one direction only. In AC, electrons "saw" back
and forth in the load. AC is easier to manufacture and is most often
delivered and used in a residence, business, or factory.
- True, Intrinsically safe areas are safe with out enclosure, but enclosure are required for other protections.
- NEC 250.66 provides the sizing of grounding electrode conductors
- A Direct burial clamp is needed to properly connect number 4 copper to a ground rod.
- A bonding screw is green.
- False, Fuses on the load side do not protect the transformer.
- 1. Branch circuit in which the initial run is encased in AC up to the first receptacle, which is mounted in a plastic box.
2. Branch circuit in which the initial run is encased in AC up to the first receptacle, which is mounted in a metal box.
3. clothes closet measuring more than 10 sq ft.
- NEC 220.16 - 220.20 cover appliance calculations.
- A bonding jumper should be installed inside or outside raceway within 6ft. of attachment. (NEC 250.118)
- Heat, Magnetism, and Light
not required by NEC, in general any receptacles below grade, including
those in finished basements, should be GFCI protected. Receptacles in
dwelling accessory building with floors at or below grade level require
GFCI protection. unfinished basements require GFCI-protected
- Mechanical and Electrical continuity conductors.
- NEC Section 250-119 1-14
- A 12in. counter requires a receptacle because it holds small appliances.
- A gounding system is connected to the ground or to a conductive body that extends the ground connection.
- Ground and Arc are two types of electrical faults.
- Per NEC 230.40, "Every service drop or lateral shall supply only one set of service entrance conductors."
- Chapter 9
- False, a A/C unit needs only 220 and a ground to complete the circuit.
- Ground Rod
NEC 450.3, phases must arrange in a particular order: A, B, C, from
left to right or from top to bottom as seen from the front.
- True, Per NEC 422.31
- NEC Article 250
lacks insulation qualities because it conducts electricity. As a
result, it is one of the most hazardous substances in an electrical
- False, Per NEC 450.4 a OCPD is no needed.
- False, Current is fatal to people not Voltage
- Although a 15amp breaker is above code, it is preferable when considering expansion.
must be installed on a peninsula when the peninsula's long edge is at
least 24in. and its short edge is at least 12in.
- A mandatory act or condition
- To test conduit for proper grounding, check ohms or use 120V receptacle and touch to ground to check for voltage.
- True, Per NEC 300.11 hanging a second support when running new over old is acceptable and a common practice.
- A grounding conductor is a conductor or circuit of a wiring system to a grounding electrode (ground rod).
- To ground a subpanel in the another building, run bare copper wire from subpanel to ground rod inside or outside.
- NEC Article 408 covers panel board applications.
- NEC 110.23 states that, "Unused current transformers associated with potentially energized circuits shall be short circuited."
all equipment must be installed per manufacturer's instructions and
specifications, The apparatus is void and violates NEC if this is not
- According to new codes, ARC fault protection is needed many additional parts of the house.
- Per NEC 250.26, The Neutral conductor serves as ground.
- Two hots are needed to operate the heater neutral. The timers can serve as ground for tripping mechanism.
- Chapter 5
sizes of copper and aluminum wire, as well as the coating of wire that
has fewer than three current carrying wires in a cable or conduit or
that is buried in the earth.
- Per NEC 220.84, A 21 unit building would be rated at 32% and any occupancy over 62 units rated at 23%
- False, via a green wire
- High impedance grounding is used for grounding radio towers. NEC 250.20(E)
- Per NEC 422.11, The size of the breaker to use.
- NEC Article 230
- NEC 300.5, provides requirements up to 600V
- Per NEC 680.90(A), GFCI protection Must reside on whirlpool tubs.
- False, grounding conuctors belong on the green screws.
- False, unless it is 8ft above the rim of the shower zone and listed for wet environments.
- NEC is also know as the NFPA 70
- Terms and Definitions
- Per NEC 100, Property owners can act as their own "Authority Having Jurisdiction" (AHJ)
to NEC Article 100, a device that opens and closes a circuit by
nonautomatic means automatically closes for a predetermined overcurrent.
- Chapter 9, Table 4 outlines trade size of conduit as well as raceway size.
- False, No disconnect is required.
- Circuit Breaker
- False, NEC does not approve tress as service conductors.
- False, the smaller the diameter increases resistance to flow.
can use sheet metal screws for bonding when those screws are green and
have hexagonal heads (NEC 250.8), but it is generally considered unwise.
make a proper grounding system using three 200-amp disconnects, use a
ground wire of sufficient size to go from panel to panel with a lug,
screw, or ground bar, if provided.
determine whether the application is residential. For residential
applications, the NEC provides no guidance. The answer for
nonresidential applications is based on box fill. For these
applications, most electricians calculate between 1 and 1.5 amperes per
- The thicker the wire. Gauge was designed to reflect the number of wires that can fit through an opening.
- 20ft. of bare copper not smaller than 2 AWG
- 6.25amps, 750 watts divided by 120V is 6.25amps
- Equipment fastened or connection between metal parts.
- NEC Articles 342, 344, and 358 outline the installation requirements of RMC, IMC, and EMT.
- Per NEC 392.7(B) Bonding of all cable tray sections is required.
- Per NEC 225.34, a maximum of six disconnects are allowed per service entrance.
- False, The term electricity is defined as the imbalance in the negative charges, or electrons, between two points.
- True, Per NEC Article 400, only when rated for wet areas.
- NEC Article 517
current, in amperes, that a conductor can carry continuously under the
conditions of use without exceeding its temperature rating"
- False, NEC 402.5 defines ampacity requirements for fixture wires.
- Resistive, impedance, and skin effect.
- True, It is a good idea to exceed the requirements by a foot or two.
- Liquid Filled and Dry Versions
fibrillation is the major cause of death from electrical shock. The
shock disrupts the normal electrical brain to heart signals.
NEC 450.46 only transformers over 100KW require a drain, however
installing a drain in case of dielectric spills is good practice.
receptacle with NEMA 5-20R on it has an amperes rating of 20, will take
a NEMA-5-15P or NEMA-5-20P plug, and has a voltage rating of 125.
- Breaker Rating determines ampacity, or size, of a circuit.
- Deicing systems
garage space is not considered livable space, subtract its area from
the total living area. The home's livable area 28 x 40 is 1,120ft.
NEC 220.13, use 100% of the first 10KW and 50% of the demand above
10KW. In this case, the demand factor would be 10,000 plus half the
remaining 10,000 or 15,000W
- NEC Article 392
- True (NEC 250.92B)
- Bonding jumpers
- 1. Bonding jumper is sized not less than 12.5% of the largest phase conductor.
2. Based on the largest ungrounded service conductor.
3. Based on the largest sum of the service conductors.
- False, Per NEC 450.23-26 liquid-filled transformers have different requirements based on the dielectric fluid.
- Two hots are needed to operate the stove neutral. The timers and clocks can serve as ground for tripping mechanism.
- Smaller its AWG
- False, NEC 312.3, disallows recessing panels in flammable walls.
- Three residential areas that require 20-amp circuits are the kitchen, bathroom, and laundry room.
- sledge hammer, hammer drill, and ground rod pounders
- NEC requires a clearance width of 30in. and a clearance depth of 36in.
- In a parallel circuit, each load is connected in a separate path. In a circuit schematic, the branch lines are parallel.
- NEC Section 250-118
- Annex C of NEC covers conduit and tubing fill for conductors and fixture wire fill.
locate wire type and size to be installed. Repeat for each conductor,
keeping a running total. Derate by 40% to ge the total raceway area.
- 15v 120V/8
- Damage may occur in the meter and or personal injury.
- The National Fire Protection Association (NFPA) sponsors the NEC
- NEC Table 250.66
- Chapter 3
- amperes, named after the French scientist, Andre Marie Ampere
- False, ceiling tiles are never appropriate device support.
like a refrigerator the appliance should continue running when another
component fails, the grounding system must be able to support the
service on its own.
- Per NEC 402.3, FFH-2 fixture wiring is useable up to 75 degrees C
- NEC requires a minimum of 3 watts per residential sq ft. The kitchen may require more for better lighting.
- NEC 90.1(C)
- True, Per NEC 422.31
- False, A bonding screw is unneeded in a subpanel.
circuit conductors between the service equipment, the source of a
separately derived system, or other power source of a separately derived
system, or other power supply source and the final branch-circuit
- False, a TVSS is only for protecting against predictable anomalies, and short-duration spikes of high-voltage.
- Exothermic welding involves the fusion of metal materials or copper to rebar.
- 14 gauge; 2
12 gauge; 2.25
10 gauge; 3
- Yes, a receptacle is required in close proximity to an air-conditioning unit. At most, it must be 25ft. distant.
- 7.5amps, 1,800 watts divided by 240V is 7.5amps
- 1. Air-borne Particulate
receptacle or switch counts as 2 conductors, and 14 AWG wire conductors
require 2 cu.in. each. Therefore, 2 conductors x 2 cu.in. = 4 cu. in.
Add to this 2 for the yoke and 2 for the ground for a total 0f 8 cu.in.
- Given that power equals voltage times resistance, power in this example is 24 watts (2amp x 12V)
Pipe, A grounding system designed as a main service ground takes
priority over a system that provides grounding alone. While requiring as
large a grounding surface area as possible is advantageous, the
grounding system must be able to support the service on its own.
- The size of the largest conductor determines what size ground wire used on a service.
- An isolated grounded reciprocal is a separate ground from a device directly to a panel.
- Equipment Bonding Jumpers
- NEC Article 386 covers metallic or metal raceway; NEC Article 388 covers PVC pipe.
- Marked CO/ALR
- False, The negative terminal has a surplus of electrons and the positive terminal has a surplus of protons
- An Intrinsically Safe System.
- A main bonding jumper and a system bonding jumper.
NEC 90.4, 510.2, and various local codes, occupancy is permitted in the
event of a code violation as long as the occupancy remains unchanged
and no hazardous condition exists.
- To ground a subpanel in the same building, run a four-wire system from main panel to subpanel.