Exam Cheat Sheet · Quick Reference

ICC G17 Journeyman Electrician Exam (2017 NEC)

National · Pearson Vue

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

Passing score

70%

Exam time

240 min

Administered by

Pearson Vue

Format

Reference materials allowed

National State Portion 80 questions

General Knowledge 5 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)

Services and Service Equipment 9 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 +1 more

Feeders 3 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)

Branch Circuits and Conductors 15 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

Wiring Methods and Materials 21 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 +2 more

Equipment and Devices 10 Q · 12%

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 +1 more

Control Devices 3 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 means

Motors and Generators 5 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)

Special Occupancies, Equipment, and Conditions 9 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) +3 more

Key Distinctions

Chapter 9, Table 5vsChapter 9, Table 4

Table 5 gives the required area of each individual conductor while Table 4 gives the usable area inside the selected conduit or tubing; both must be used together (instead of Informative Annex C) when conductors are of different sizes or insulation types.

NEC 2017 Chapter 9, Table 5

Single-phase voltage dropvsThree-phase voltage drop

Single-phase uses a factor of 2 (round-trip length) in Vd = (2K × L × I) ÷ Cm, while three-phase replaces the 2 with 1.73 (√3).

Ugly's Electrical References 2020, Voltage Drop Calculations

Damp location receptacle (covered patio, not subject to beating rain)vsWet location receptacle

Per 406.9(A) a damp location such as a roofed open porch not subjected to beating rain needs an enclosure weatherproof only when the receptacle is covered (plug not inserted, covers closed), plus listed weather-resistant type for 15/20 A, 125/250 V nonlocking receptacles.

NEC 2017 Section 406.9(A)

Continuous loadvsNoncontinuous load

Continuous load is multiplied by 125% while noncontinuous load is counted at 100% when sizing feeder conductor ampacity (215.2(A)(1)(a)) and the feeder overcurrent device (215.3).

NEC 2017 Section 215.2(A)(1)(a)

Nontime-delay fuse for a single-phase motorvsDual element (time-delay) fuse for a single-phase motor

Per Table 430.52 the nontime-delay fuse may be rated up to 300% of full-load current, while the dual element (time-delay) fuse is limited to 175% of full-load current.

Ugly's Electrical References 2020, Page 38

Inverse time circuit breaker for a wound rotor motorvsInverse time circuit breaker for a single-phase motor

Table 430.52 allows a maximum of 150% of full-load current for a wound rotor motor versus 250% of full-load current for a single-phase motor.

Ugly's Electrical References 2020, Page 38

Instantaneous trip breaker on a DC constant-voltage motorvsInstantaneous trip breaker on AC polyphase/single-phase motors

Table 430.52 limits the DC constant-voltage motor to 250% of full-load current, far lower than the 800% allowed for AC polyphase and single-phase motors.

Ugly's Electrical References 2020, Page 38, Table 430.52

Motor branch-circuit conductor sizingvsMotor feeder conductor sizing

Branch-circuit conductors are sized at 125% of that motor's full-load current (430.22(A)), while feeder conductors are sized at 125% of the largest motor's full-load current plus the sum of the remaining motors' full-load currents.

Ugly's Electrical References 2020, Pages 41-42

GEC to a rod, pipe, or plate electrodevsGEC to a concrete-encased electrode

Per 250.66(A) the conductor need not be larger than 6 AWG copper when it is the sole connection to rod/pipe/plate electrodes, while 250.66(B) caps the sole connection to a concrete-encased electrode at 4 AWG copper.

NEC 2017 Section 250.66(A)

Motor nameplate current ratingvsTables 430.247 through 430.250 values

For general motor applications 430.6(A)(1) requires the table values (430.247–430.250), not the nameplate current, to determine conductor ampacity and ratings of switches and branch-circuit short-circuit/ground-fault protection.

NEC Section 430.6(A)(1)

Panelboard plan symbolvsJunction box plan symbol

A panelboard is a solid filled rectangle, while a junction box is a circle with the letter 'J' inside.

Lampholder symbolvsLampholder with pull switch symbol

They are two distinct plan symbols: the lampholder with a pull switch carries the added designation 'PS'.

Ugly's Electrical References 2020, Electrical Symbols

Real power in a three-phase systemvsApparent power in a three-phase system

Raising power factor at constant voltage and current increases real power (P = √3 × V × I × cos θ) but leaves apparent power unchanged.

Key Terms

Authority Having Jurisdiction (AHJ) Article 90.4(B)

Per Article 90.4, the enforcing authority responsible for interpreting the Code rules, approving equipment and materials, and granting special permission.

NEC scope exclusions (90.2) Article 90.2(D)

The Code does not cover installations in ships, watercraft other than floating buildings, railway rolling stock, aircraft, or automotive vehicles other than mobile homes and recreational vehicles.

Grounded (neutral) conductor identification, 200.6(A) NEC Section 200.6(A)

An insulated grounded conductor 6 AWG or smaller must have a continuous white or gray outer finish, or three continuous white or gray stripes over its entire length on other than green insulation; in a 120/240 V single-phase, three-wire system the neutral is white or gray and the ungrounded conductors are black and red.

Continuity of the grounded conductor, 200.2(B) NEC 2017 Section 200.2(B)

The continuity of a grounded conductor shall not depend on a connection to a metallic enclosure, raceway, or cable armor.

Delta high-leg system (120/240 V, three-phase, four-wire) Ugly's Electrical References, 2023 ed., Common Electrical Distribution Systems, Page 13 (2020 ed.: Common Electrical Distribution Systems)

A distribution system whose B phase (the high leg) must be colored orange or tagged, with caution noted for 208 volts orange to white.

Ambient temperature baseline for ampacity, 310.15(B) NEC 2017 Section 310.15(B)

Ampacity correction factors must be applied where the ambient temperature is other than the standard 30°C (86°F) baseline of Table 310.16.

Standard ampere ratings, Table 240.6(A) NEC 2017 Table 240.6(A)

The listed standard ratings for fuses and inverse time circuit breakers include values such as 45, 70, and 110 amperes; 85 amperes is not a standard rating.

Next higher standard rating rule, 240.4(B) NEC 2017 Section 240.4(B)

The next higher standard overcurrent device rating above the conductor ampacity is permitted provided the selected rating does not exceed 800 amperes and the conductors are not part of a branch circuit supplying more than one receptacle for cord-and-plug-connected portable loads.

Small conductor rule, 240.4(D)(3) NEC 2017 Section 240.4(D)(3)

14 AWG copper conductors shall have overcurrent protection not exceeding 15 amperes.

Ground-fault protection of equipment, 240.13 NEC 2017 Section 240.13

Required on solidly grounded wye systems of more than 150 volts to ground but not exceeding 1000 volts phase-to-phase for each device used as a building or structure main disconnecting means rated 1000 amperes or more.

System of coordination, 240.12 NEC 2017 Section 240.12

Where an orderly shutdown is required to minimize hazards, coordination based on (1) coordinated short-circuit protection and (2) overload indication from monitoring systems or devices is permitted.

Industrial control panel single main OCPD, 409.21(B)(2) NEC 2017 Section 409.21(B)

A single main overcurrent protective device located within the industrial control panel is permitted, and the supply conductors are then considered feeders or taps as covered by 240.21.

Part-winding start induction motor, 430.4 NEC 2017 Section 430.4

Each motor-winding connection of a standard part-winding start induction motor must have branch-circuit short-circuit and ground-fault protection rated not more than one-half that specified by 430.52.

Receptacle outlet load, 220.14(I) NEC 2017 Section 220.14(I)

Each single or multiple receptacle on one yoke is calculated at not less than 180 volt-amperes; a single piece of equipment with four or more receptacles is calculated at not less than 90 VA per receptacle.

Heavy-duty lampholder outlet, 220.14(E) NEC 2017 Section 220.14(E)

Outlets for heavy-duty lampholders are calculated at a minimum of 600 volt-amperes.

Class 1 remote-control and signaling circuits, Article 725 NEC 2017 Section 725.41(B)

Class 1 circuits are not permitted to exceed 600 volts.

Low-voltage lighting secondary circuits, 411.6(A) NEC 2017 Section 411.6(A)

Secondary circuits of low-voltage lighting systems shall not be grounded.

Service raceway conductors, 230.7 Exception No. 1 NEC 2017 Section 230.7, Exception No. 1

Although 230.7 generally prohibits other conductors in service raceways, Exception No. 1 permits grounding electrode conductors and supply-side bonding jumpers or conductors within service raceways.

Cable bending radius (Type AC and Type MC) NEC 2017 Section 320.24

Per 320.24 bends in Type AC cable must have an inner-edge radius not less than five times the cable diameter; per 330.24(B) Type MC cable with interlocked armor or corrugated sheath requires seven times the external diameter of the metallic sheath.

Outdoor overhead span minimum size, 225.6(A)(1) NEC 2017 Section 225.6(A)

For 1000 volts or less, open individual conductors must be at least 10 AWG copper for spans up to 50 ft and 8 AWG copper for longer spans unless supported by a messenger wire; open conductors must also be separated from open conductors of other circuits or systems by not less than 4 in. (225.14(C)).

Common neutral for feeders, 215.4(A) NEC 2017 Section 215.4(A)

Up to three sets of 3-wire feeders, or two sets of 4-wire or 5-wire feeders, are permitted to use a common neutral.

Series circuit current rule Ugly's Electrical References, 2023 ed., Series Circuits, Page 3 (2020 ed.: Series Circuits)

The total current in a series circuit equals the current in any other part of the circuit (IT = I1 = I2 = I3).

Formulas to Know

Ohm's Law and power relationships

I = W ÷ E (1500 W ÷ 120 V = 12.5 A); R = E ÷ I (240 V ÷ 8 A = 30 Ω); E = I × R (10 A × 12 Ω = 120 V); P = E × I; P = E² ÷ R (240² ÷ 20 = 2880 W); R = E² ÷ P (14,400 ÷ 1200 = 12 Ω)

Three-phase power and current (1.73 = √3 multiplier for the 120° phase relationship)KW = (E × I × PF × 1.73) ÷ 1000; I = (KW × 1000) ÷ (E × PF × 1.73); I = (HP × 746) ÷ (E × %EFF × PF × 1.73)

Voltage drop (inductance negligible)

Single-phase: Vd = (2K × L × I) ÷ Cm; three-phase: Vd = (1.73 × K × L × I) ÷ Cm, with K = 12.9 for copper at 75°C, L = one-way length in feet, I = amperes, Cm = circular mils. Vd is proportional to length, so a 20% longer run raises a 3% drop to 3.6%; one standard size up adds ~26% circular mils and cuts Vd ~20%, restoring the 3% limit.

Feeder conductor ampacity and feeder OCPD with continuous and noncontinuous loads

Minimum = noncontinuous load + (1.25 × continuous load); e.g., 120 A + (80 A × 1.25) = 220 A conductor ampacity (215.2(A)(1)(a)); 40 A + (1.25 × 80 A) = 140 A OCPD (215.3)

Ampacity adjustment and temperature correction

4 through 6 current-carrying conductors in a raceway: multiply table ampacity by 0.80 (100 A × 0.80 = 80 A at 30°C base); at 40°C (104°F) ambient with 75°C-rated conductors multiply base ampacity by the 0.88 correction factor

Ampacity of parallel conductor sets

Total ampacity = single-set table ampacity × number of sets; 350 kcmil THHN copper at 90°C = 350 A, two parallel sets = 350 × 2 = 700 A

Motor branch-circuit and feeder conductor sizing

Branch circuit: 125% × full-load current (430.22(A)); 1.25 × 65 A = 81.25 A. Feeder: 125% of the largest motor's FLC plus the sum of the other motors' full-load currents.

Motor branch-circuit short-circuit/ground-fault device sizing with next-size-up

Nontime-delay fuse = 300% × FLC (300% × 65 A = 195 A); where the result is not a standard size, 430.52(C)(1) Exception No. 1 permits the next standard size from Table 240.6(A) (200 A). Single-phase inverse time breaker = 250% × FLC (250% × 50 A = 125 A), and if the motor will not start, the next higher standard size (150 A) is permitted.

Hermetic refrigerant motor-compressor circuit sizing

Conductors ≥ 125% × RLA (440.32): 1.25 × 30 A = 37.5 A, 1.25 × 20 A = 25 A. OCPD ≤ 175% × RLA (440.22(A)): 1.75 × 30 A = 52.5 A → 50 A standard size (the 2017 NEC has no next-higher-size exception here); 1.75 × 20 A = 35 A. If the device cannot carry starting current, it may be increased to a maximum of 225% of RLA.

Dwelling-unit general load calculation (Article 220)

General lighting = 3 VA/sq ft (Table 220.12) + 1500 VA per small-appliance circuit + 1500 VA laundry circuit; 2000 sq ft: 6000 + 3000 + 1500 = 10,500 VA; 1200 sq ft unit: 3600 + 3000 + 1500 = 8100 VA, × 4 units = 32,400 VA before demand factors

DC resistance corrected for temperature (Chapter 9, Table 8 notes)R2 = R1[1 + α(T2 − 75)], where α(copper) = 0.00323 at 75°C (167°F)

Start free practice Full study guide