Verified, not estimated. Every figure below is drawn from the official exam structure we maintain — question counts, passing standard and topic weighting. Practice questions are grounded in the source law with statute citations. We omit any figure we can't verify rather than guess at it.
Total questions
80
Passing score
70%
Exam time
240 min
Administered by
Pearson Vue
Format
Reference materials allowed
National State Portion
80 questions
General Knowledge5 Q · 6%
Electrical Theory and General Electrical Load CalculationsCode Definitions and TermsPlan ReadingNEC Code Structure, Scope, and Enforcement (Article 90)Equipment Approval, Listing, Labeling, and IdentificationWorking Space and Clearances Around Electrical Equipment (Article 110)Electrical Connections, Terminations, and Temperature RatingsArc-Flash Hazard Warnings, Equipment Markings, and Disconnecting Means IdentificationAC/DC Distribution System Configurations and Conductor Color CodingPower Factor, Impedance, Reactance, and Capacitance CalculationsApplied Math for Electricians (Fractions, Equations, Trigonometry, and Unit Conversions)Article 110 - Requirements for Electrical Installations+2 more
Services and Service Equipment9 Q · 11%
Services and Fault CurrentService Load CalculationsService Equipment & Service ConductorsTransformersSystem Grounding and BondingTemporary Service WiringNumber of services permitted and service configurationsOverhead and underground service conductor requirements and clearancesService disconnecting means requirements and ratingsService overcurrent protection requirementsArc-flash hazard warning labels for service equipmentSurge arresters and surge-protective devices (SPDs) at services+4 more
Feeders3 Q · 4%
Load CalculationsEquipment GroundingMinimum feeder conductor ampacity and sizing (Article 215)Overcurrent protection requirements for feedersFeeder conductor identification (grounded, ungrounded, and EGC)Ground-fault protection of equipment for feeders rated 1000A or moreOutside feeder installation requirements (clearances, wiring methods, disconnecting means)Neutral load calculations and demand factors for feedersDemand factors for dwelling and non-dwelling feeder loads (lighting, appliances, cooking equipment, dryers)Article 215 - Feeders
Branch Circuits and Conductors15 Q · 19%
Branch Circuit CalculationOvercurrent ProtectionConductorsRequired Outlets & GFCI/AFCI ProtectionEquipment GroundingVoltage Drop Calculations (Single-Phase and Three-Phase)Conductor Insulation Types and Application EnvironmentsAmpacity Correction and Adjustment Factors (Temperature and Conduit Fill)Multiwire Branch Circuit RequirementsGrounded Conductor Identification and UseBranch-Circuit Voltage LimitationsFeeder and Service Load Demand Factors+3 more
Wiring Methods and Materials21 Q · 26%
Raceway InstallationsUnderground Wiring MethodsBoxes and EnclosuresCabinets, Panelboards, & SwitchboardsClearance and GuardingFlexible Cords and CablesCable Wiring Methods (NM, AC, MC, MI, SE, UF, TC, MV)Conductor Fill Calculations and Conduit SizingPhysical Protection of Cables and RacewaysConduit Bending Techniques and CalculationsWireways, Auxiliary Gutters, and BuswaysCable Trays and Cablebus Systems+12 more
Equipment and Devices10 Q · 13%
LuminairesReceptacles, Switches and Other DevicesAppliances and Other EquipmentOther Utilization EquipmentHeating and Cooling EquipmentFixture Wire Types, Ampacity, and Installation RequirementsNEMA Receptacle and Attachment Plug ConfigurationsLighting Track Installation and Construction RequirementsLow-Voltage Lighting System RequirementsRecessed Luminaire Installation and Clearance RequirementsDisconnecting Means for Fixed Electric Space-Heating EquipmentDisconnecting Means for Air-Conditioning and Refrigerating Equipment+5 more
Control Devices3 Q · 4%
Switches, Disconnects and ControllersMotor controller ratings and marking requirements (NEC Article 430)Motor control circuit overcurrent protection and wiring (Article 430 Part VI)Motor disconnecting means types, location, and ratings (Article 430 Part IX)Stop-start station control circuits and jogging/inching circuitsHand-off-automatic (HOA) control schemesClass 1, Class 2, and Class 3 remote-control circuit classifications and power limitationsMotor control centers: overcurrent protection, grounding, and busbar requirementsIndustrial control panel overcurrent protection, short-circuit ratings, and disconnecting meansArticle 430 - Motors, Motor Circuits, and Controllers
Motors and Generators5 Q · 6%
MotorsGeneratorsMotor branch-circuit conductor sizing (125% FLC rule)Motor branch-circuit short-circuit and ground-fault protection (Table 430.52 ratings)Motor overload protection (overload device selection and trip settings)Motor disconnecting means (types, ratings, and location requirements)Motor controllers (ratings, types, and marking requirements)Motor control centers (overcurrent protection, grounding, and marking)Locked-rotor current and code lettersCapacitors in motor circuits (conductor sizing, disconnecting means, and overload device adjustment)Article 430 - Motors, Motor Circuits, and Controllers
Special Occupancies, Equipment, and Conditions9 Q · 11%
Special OccupanciesSwimming Pools and Similar InstallationsMobile Home and RV ParksData Processing EquipmentMiscellaneous Special EquipmentEmergency SystemsSignaling and Fire Alarm SystemsHazardous Location Classification (Classes I, II, III; Divisions 1 and 2; Zones 0, 1, 2, 20, 21, 22)Wiring Methods and Equipment for Hazardous LocationsSpecific Hazardous Occupancies (Commercial Garages, Aircraft Hangars, Motor Fuel Dispensing, Bulk Storage, Spray Application)Health Care Facilities Wiring and Essential Electrical SystemsStandby and Backup Power Systems (Legally Required Standby, Optional Standby, Critical Operations Power Systems, Fire Pumps)+7 more
Key Distinctions
Unventilated pit in a major repair garagevsUnventilated pit in a minor repair garage
Without mechanical ventilation a pit/belowgrade work area in a major repair garage is Class I, Division 1 [511.3(C)(3)(b)], while the same unventilated pit or depression below floor level in a minor repair garage is Class I, Division 2 extending up to floor level [511.3(D)(3)(b)]; a major-garage pit becomes Division 2 only where mechanical ventilation provides at least six air changes per hour.
Equipment terminations for circuits rated 100 amperes or less, or marked for 14 AWG through 1 AWG, are limited to 60°C ampacity unless the equipment is listed and identified for higher-temperature conductors, whereas the 75°C basis applies to circuits rated over 100 amperes; higher-temperature conductors may still be used for ampacity adjustment or correction.
NEC 2014 Section 110.14(C)(1)(a)
800 A panic-hardware rule [110.26(C)(3)]vs1200 A two-entrance rule [110.26(C)(2)]
Where equipment rated 800 A or more containing overcurrent, switching, or control devices has a personnel door less than 7.6 m (25 ft) from the nearest edge of the working space, that door must open in the direction of egress with listed panic hardware; the 1200 A figure instead triggers the requirement for two entrances to the working space.
Single-phase uses the factor 2 for the out-and-back length of both conductors, VD = (2 × K × I × L)/CM, while three-phase substitutes 1.732 (√3) for the 2, VD = (1.732 × K × I × L)/CM.
Copper K = 12.9vsAluminum K = 21.2
Aluminum has roughly 1.6 times the resistance of copper, so its K constant (21.2) is higher than copper's (12.9) and yields a larger calculated voltage drop for the same size, current, and length.
Service lateralvsService drop / underground service conductors
A service lateral is the underground conductors between the utility electric supply system and the service point; a service drop is the overhead equivalent, and underground service conductors run from the service point to the first point of connection to the service-entrance conductors.
NEC 2014 Article 100 — Definitions of Service Lateral and Service Point
Heavy-duty lampholder outlet — 600 VA [220.14(E)]vsReceptacle outlets — 180 VA per yoke, or 90 VA per receptacle for a single piece of equipment with four or more receptacles [220.14(I)]
Outlets supplying heavy-duty lampholders are calculated at a minimum of 600 volt-amperes each; receptacle outlets are calculated at not less than 180 VA for each single or multiple receptacle on one yoke, except that a single piece of equipment consisting of a multiple receptacle comprised of four or more receptacles is calculated at not less than 90 VA per receptacle (sign and outline lighting outlets use 1200 VA under 220.14(F)).
NEC 2014 Section 220.14(E)
Multioutlet assembly — 5 ft increment [220.14(H)(1)]vsMultioutlet assembly — 1 ft increment [220.14(H)(2)]
Where the connected appliances are unlikely to be used simultaneously, each 1.5 m (5 ft) or fraction thereof of each separate and continuous length counts as one outlet of not less than 180 VA; where they are likely to be used simultaneously, each 1 ft or fraction thereof is treated as an outlet.
NEC 2014 Section 220.14(H)
18 AWG copper at 7 A [240.4(D)(1)]vs16 AWG copper [240.4(D)(2)]
18 AWG copper may be protected at 7 amperes only where continuous loads do not exceed 5.6 amperes and the protection is a branch-circuit-rated breaker or fuse listed for 18 AWG copper or a Class CC, J, or T fuse; the 8-ampere continuous limit belongs to 16 AWG copper.
On an outlet of a dwelling branch circuit required to have AFCI protection, only a listed outlet branch-circuit type AFCI receptacle, a receptacle protected by one, or a receptacle protected by a listed combination-type AFCI breaker is permitted; a GFCI receptacle provides ground-fault protection for personnel, not arc-fault protection (tamper-resistance is a separate requirement).
NEC 2014 Section 406.4(D)(4)
Inverse time breaker increase for motors 100 A or lessvsInverse time breaker increase for motors over 100 A
Under 430.52(C)(1) Exception No. 2, where the motor will not start at the Table 430.52 setting (up to 250% of FLC for an inverse time breaker), the rating may be increased but shall in no case exceed 400% of full-load current for motors of 100 A or less, versus 300% for motors above 100 A.
NEC Section 430.52(C)(1), Exception No. 2; Table 430.52(C)(1)
EMT supported by framing-member openings — 10 ft [358.30(B)]vs358.30(A) Exception No. 1 — 5 ft
Horizontal EMT runs supported by openings through framing members are permitted where the openings occur at intervals not greater than 3 m (10 ft) and the tubing is securely fastened within 900 mm (3 ft) of terminations; the 5 ft figure applies only to the Exception No. 1 increase for unbroken lengths where structural members do not readily permit fastening within 3 ft.
NEC 2014 Section 358.30(B)
Key Terms
In Sight From (Within Sight From, Within Sight) NEC 2014 Article 100 — Definition of In Sight From (Within Sight From, Within Sight)
Equipment that is visible from and not more than 15 m (50 ft) distant from the other equipment — both the visibility and the 50 ft limit must be met.
Continuous Load NEC 2014 Article 100 — Definition of Continuous Load
A load where the maximum current is expected to continue for 3 hours or more, which drives the 125 percent sizing rules for branch circuits and feeders.
Dwelling, Multifamily NEC 2014 Article 100 — Definition of Dwelling, Multifamily
A building that contains three or more dwelling units (two units is a two-family dwelling, one unit is a one-family dwelling).
Copper-Clad Aluminum Conductors NEC 2014 Article 100 — Definition of Copper-Clad Aluminum Conductors
Conductors drawn from a copper-clad aluminum rod with the copper metallurgically bonded to an aluminum core, the copper forming a minimum of 10 percent of the cross-sectional area of a solid conductor or each strand.
Overcurrent Protective Device, Branch-Circuit NEC 2014 Article 100 — Definition of Overcurrent Protective Device, Branch-Circuit
A device capable of protecting service, feeder, and branch circuits over the full range of overcurrents between its rated current and its interrupting rating, with an interrupting rating of not less than 5000 amperes.
Surge-Protective Device (SPD), Type 1 NEC 2014 Article 100 — Definition of Surge-Protective Device (SPD)
A permanently connected SPD intended for installation between the secondary of the service transformer and the line side of the service disconnect overcurrent device (Type 2 is load side of that device, Type 3 is point-of-utilization, Type 4 is a component SPD).
Volatile Flammable Liquid NEC 2014 Article 100 — Definition of Volatile Flammable Liquid
A flammable liquid having a flash point below 38°C (100°F), a flammable liquid whose temperature is above its flash point, or a qualifying Class II combustible liquid whose temperature is above its flash point.
Branch Circuit, Individual NEC 2014 Article 100 — Definition of Branch Circuit, Individual
A branch circuit that supplies only one utilization equipment (a general-purpose branch circuit supplies two or more receptacles or outlets; a multiwire branch circuit has two or more ungrounded conductors sharing a grounded conductor).
Approved NEC 2014 Article 100 — Definition of Approved
Acceptable to the authority having jurisdiction; Listed and Labeled involve a product evaluation organization acceptable to the AHJ, and Identified means recognizable as suitable for a specific purpose or application.
Main bonding jumper (250.24(B)) NEC 2014 Section 250.24(B)
An unspliced jumper, installed per 250.28, that connects the equipment grounding conductors and service-disconnect enclosure to the grounded conductor within the enclosure for each service disconnect; it may be a wire, bus, screw, or similar suitable copper or corrosion-resistant conductor sized from Table 250.102(C)(1).
Working space width (110.26(A)(2)) NEC 2014 Section 110.26(A)(2)
The width of working space in front of electrical equipment must be the width of the equipment or 762 mm (30 in.), whichever is greater, and must permit at least a 90-degree opening of equipment doors or hinged panels.
Dedicated electrical space (110.26(E)(1)(a)) NEC 2014 Section 110.26(E)(1)(a)
The space equal to the width and depth of indoor equipment extending from the floor to a height of 1.8 m (6 ft) above the equipment or to the structural ceiling, whichever is lower, in which piping, ducts, or other foreign equipment may not be located (suspended ceilings with removable panels are the only stated exception).
Guarding by elevation (110.27(A)(4)) NEC 2014 Section 110.27(A)(4)
Exposed live parts may be guarded by elevation above the working surface: minimum 2.5 m (8 ft) for 50 to 300 volts and minimum 2.6 m (8 ft 6 in.) for 301 to 600 volts (e.g., a 480-volt installation requires 8 ft 6 in.).
Concrete-encased electrode (250.52(A)(3)) NEC 2014 Section 250.52(A)(3)
An electrode whose metallic components are encased by at least 50 mm (2 in.) of concrete, located within that portion of a foundation or footing in direct contact with the earth.
Ground ring (250.52(A)(4)) NEC 2014 Section 250.52(A)(4)
An electrode encircling the building in direct contact with the earth consisting of at least 6.0 m (20 ft) of bare copper conductor not smaller than 2 AWG (4 AWG is the bare copper size for a concrete-encased electrode).
Rod-type grounding electrode (250.52(A)(5)) NEC 2014 Section 250.52(A)(5)
Stainless steel and copper- or zinc-coated steel rod electrodes must be at least 15.87 mm (5/8 in.) in diameter unless listed; the 3/4 in. figure is the minimum trade size for a pipe or conduit electrode.
Formulas to Know
Single-phase voltage drop (and its rearrangements)VD = (2 × K × I × L) / CM; solve for length L = (VD × CM)/(2 × K × I); for minimum size CM = (2 × K × I × L)/VD; for maximum load I = (VD × CM)/(2 × K × L). Use K = 12.9 for copper, K = 21.2 for aluminum; the factor 2 accounts for the out-and-back length of both conductors. Allowable drop at 3 percent = source volts × 0.03.
Three-phase voltage dropVD = (1.732 × K × I × L) / CM — e.g., (1.732 × 12.9 × 24 A × 90 ft)/10,380 cmil = 4.65 V.
Percentage voltage drop% VD = voltage drop ÷ source voltage — e.g., 8.4 V ÷ 240 V = 3.5 percent (3 percent is the recommended branch-circuit value).
Wye system line voltageLine-to-line voltage = line-to-neutral voltage × 1.732 — e.g., 277 V × 1.732 = 480 V (480Y/277).
Current from powerI = P / E — e.g., 1,800 W ÷ 120 V = 15 A.
Minimum motor feeder conductor ampacity (430.24)125% of the largest motor FLC + the FLC of each other motor — e.g., three 15.2 A motors: (1.25 × 15.2) + 15.2 + 15.2 = 49.4 A.
Motor branch-circuit inverse time breaker sizingTable 430.52(C)(1) maximum = 250% of motor FLC (50 A × 2.5 = 125 A); if the motor fails to start, 430.52(C)(1) Exception No. 2 permits an increase not exceeding 400% of FLC for motors of 100 A or less (50 A × 4 = 200 A; 60 A × 4 = 240 A) and 300% above 100 A — it is not simply the next standard size.
Hermetic refrigerant motor-compressor and generator conductor sizingCompressor branch-circuit conductors ≥ 125% of RLA (440.32) and OCPD rated not more than 175% of RLA (440.22(A)) — 20 A RLA gives 25 A conductors and a 35 A maximum OCPD; generator output conductors must have ampacity not less than 115% of nameplate current (445.13) — 200 A × 1.15 = 230 A.
EMT offset bends (Ugly's chart)Distance between the two bend marks = multiplier × offset depth (45° multiplier 1.4; 22-1/2° multiplier 2.6) — 1.4 × 5 = 7 in; 1.4 × 4 = 5-5/8 in; 2.6 × 10 = 26 in. Shrink from the chart is added to the measured distance to locate the FIRST mark (42 in + 1-7/8 in = 43-7/8 in for the 10-in 22-1/2° offset; 48 in + 1-1/2 in = 49-1/2 in for the 4-in 45° offset; 36 in + 4-1/2 in = 40-1/2 in). Shrink per inch of offset is taken from the chart for the particular bend, not a single universal rate — e.g., Figure EO-5: 1/4 in per inch × 4 in = 1 in; Figure EO-6: 1/2 in per inch × 9 in = 4-1/2 in.
EMT 3-point saddle and 90° stub-up (Ugly's)3-point saddle: side marks = 2.5 × obstruction height each side of the center mark (2.5 × 3 in = 7-1/2 in; 2.5 × 6 in = 15 in), center bent 45° and sides 22-1/2°, shrink = 3/16 × obstruction height. Stub-up: mark = stub height − take-up (18 − 5 = 13 in for 1/2 in EMT; 16 − 11 = 5 in for 1-1/4 in EMT).
