Exam Cheat Sheet · Quick Reference
ICC G16 Master 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
100
Passing score
75%
Exam time
300 min
Administered by
Pearson Vue
Format
Reference materials allowed
National State Portion 100 questions
General Knowledge
12 Q · 12%
Electrical Theory and General Electrical Load CalculationsCode Definitions and TermsPlan ReadingNEC Purpose, Scope, and Code ArrangementEquipment Approval, Listing, and Labeling RequirementsGeneral Installation Requirements (Article 110)Working Space and Clearances Around Electrical EquipmentConductor Materials, Sizes, and Temperature RatingsElectrical Symbols and Wiring DiagramsUnits of Measurement, Conversions, and Math FundamentalsAC Circuit Properties (Impedance, Reactance, Inductance, Capacitance, Power Factor)
Services and Service Equipment
16 Q · 16%
Services and Fault CurrentService Load CalculationsService Equipment & Service ConductorsTransformersSystem Grounding and BondingTemporary Service WiringService entrance conductor installation methods and clearancesService disconnecting means requirements and ratingsOvercurrent protection for services and transformersGrounding electrode system types and installationEquipment grounding conductor sizing and identificationSurge arresters and surge-protective devices (SPDs)
+1 more
Feeders
4 Q · 4%
Load CalculationsEquipment GroundingFeeder conductor sizing and ampacity requirementsOvercurrent protection for feedersFeeder neutral load calculations and demand factorsOutside feeders: clearances, conductor sizing, and disconnecting meansDemand factors for dwelling and non-dwelling feeder loadsGround-fault protection of equipment for feedersFeeder conductor identification requirements
Branch Circuits and Conductors
16 Q · 16%
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 FactorsGrounded Conductor Identification and UseMultiwire Branch CircuitsBranch-Circuit Voltage Limitations
Wiring Methods and Materials
19 Q · 19%
Raceway InstallationsUnderground Wiring MethodsBoxes and EnclosuresCabinets, Panelboards, & SwitchboardsClearance and GuardingFlexible Cords and CablesCable Wiring Methods (NM, AC, MC, MI, SE, UF, TC, MV, FCC, FC, IGS cable types)Conduit and Tubing Types (RMC, IMC, EMT, FMC, LFMC, PVC, HDPE, RTRC, ENT, LFNC, FMT)Conductor Fill and Conduit Sizing (percent fill, conductor area tables, conduit dimensions)Conduit Bending Methods (90° bends, offsets, saddle bends, back-to-back, multi-shot)Wireways, Auxiliary Gutters, Busways, and Cable TraysGeneral Wiring Requirements (physical protection, conductor grouping, fire spread, temperature limitations)
+2 more
Equipment and Devices
10 Q · 10%
LuminairesReceptacles, Switches and Other DevicesAppliances and Other EquipmentOther Utilization EquipmentHeating and Cooling EquipmentFixture Wire Types, Ampacity, and Installation RequirementsNEMA Receptacle and Plug ConfigurationsLighting Track Installation and Construction RequirementsLow-Voltage Lighting Systems (Article 411)Disconnect Requirements for Fixed Electric Heating EquipmentOvercurrent Protection for Resistance Heating ElementsGround-Fault Protection for Deicing, Snow-Melting, and Pipeline Heating Equipment
+1 more
Control Devices
3 Q · 3%
Switches, Disconnects and ControllersMotor controller ratings and markings (horsepower, voltage, short-circuit current)Motor control circuit overcurrent protection and wiring (Article 430 Part VI)Motor disconnecting means types, location, and ampere ratingsMotor control center construction, overcurrent protection, and groundingClass 1, Class 2, and Class 3 remote-control circuit classifications and power source requirementsStop-start station wiring and control relay circuits (jogging, hand-off-automatic)Industrial control panel overcurrent protection, short-circuit current rating, and disconnecting meansElectronic lighting control switches and dimmer switch ratings (Article 404)
Motors and Generators
8 Q · 8%
MotorsGeneratorsMotor branch-circuit conductor sizing (125% FLC rule)Motor branch-circuit short-circuit and ground-fault protection (Table 430.52)Motor overload protection (sizing and placement of overload devices)Motor disconnecting means (type, location, and rating requirements)Motor controllers (ratings, types, and design requirements)Motor control centers (overcurrent protection, grounding, and busbar requirements)Capacitors in motor circuits (conductor sizing, discharge requirements, and effect on overload device settings)Phase converters (conductor ampacity, overcurrent protection, and disconnecting means)
Special Occupancies, Equipment, and Conditions
12 Q · 12%
Special OccupanciesSwimming Pools and Similar InstallationsMobile Home and RV ParksData Processing EquipmentMiscellaneous Special EquipmentEmergency SystemsSignaling and Fire Alarm SystemsHazardous (Classified) Locations — Class I, II, and III Division and Zone ClassificationProtection Techniques for Hazardous Locations (explosionproof, intrinsically safe, dust-ignitionproof, pressurized)Specific Hazardous Occupancies (commercial garages, aircraft hangars, motor fuel dispensing, bulk storage, spray finishing)Health Care Facilities — Essential Electrical Systems and Patient Care WiringStandby and Emergency Power Systems (legally required standby, optional standby, critical operations power systems, fire pumps)
+3 more
Key Distinctions
Main bonding jumpervsSystem bonding jumper
Per NEC Article 100, the main bonding jumper is the connection between the grounded circuit conductor and the equipment grounding conductor at the service, while the system bonding jumper makes that same connection (to the supply-side bonding jumper, the equipment grounding conductor, or both) at a separately derived system.
NEC 2017 Article 100 (Definition: Bonding Jumper, Main)Chapter 9, Table 5vsChapter 9, Table 4
Table 5 gives the required area of each individual conductor while Table 4 gives the usable area within the selected conduit or tubing, and both must be used together when conductors are of different sizes or insulation types (instead of the Informative Annex C tables).
NEC 2017 Chapter 9, Table 5GEC to rod, pipe, or plate electrode [250.66(A)]vsGEC to concrete-encased electrode [250.66(B)]
A grounding electrode conductor connected solely to single or multiple rod, pipe, or plate electrode(s) is not required to be larger than 6 AWG copper, whereas the portion that is the sole connection to a concrete-encased electrode is not required to be larger than 4 AWG copper.
NEC 2017 Section 250.66(A)Nontime-delay fuse, single-phase motorvsDual-element (time-delay) fuse, single-phase motor
Per Table 430.52, the maximum rating for a nontime-delay fuse on a single-phase motor is 300% of full-load current, while a dual-element (time-delay) fuse has a maximum of 175% of full-load current.
Ugly's Electrical References 2020, Page 38Instantaneous trip breaker, DC constant voltage motorvsInstantaneous trip breaker, AC polyphase or single-phase motor
Per Table 430.52, the maximum setting for an instantaneous trip breaker is 250% of full-load current for a direct-current constant voltage motor, versus the 800% allowed for AC polyphase and single-phase motors.
Ugly's Electrical References 2020, Page 38, Table 430.52Wye-start, delta-run motor conductors [430.22(C)]vsPart-winding connected motor conductors [430.22(D)]
Conductors between controller and motor shall not be less than 72 percent of motor full-load current for a wye-start, delta-run motor (58% × 1.25), but not less than 62.5 percent for a part-winding connected motor (50% × 1.25).
NEC 2017 Section 430.22(C)Motor branch-circuit conductor sizingvsMotor feeder conductor sizing
Branch-circuit conductors are sized at 125% of the 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 41-42Generator output conductors (445.13)vsMotor branch-circuit conductors (430.22(A))
Conductors from the generator terminals to the first overcurrent device must have ampacity of not less than 115% of the generator nameplate current, whereas motor branch-circuit conductors must be sized at 125% of motor full-load current.
Ugly's Electrical References 2020, Pages 41-42Single-phase voltage drop calculationvsThree-phase voltage drop calculation
The single-phase calculation uses a factor of 2, while the three-phase calculation replaces it with 1.73 (the square root of 3): Vd = (1.73 × K × L × I) ÷ Cm.
Ugly's Electrical References 2020, Voltage Drop CalculationsDamp location receptacle (roofed open porch/patio, not subject to beating rain)vsWet location receptacle
Per 406.9(A), a receptacle in a damp location such as a covered patio with open sides not subjected to beating rain or runoff needs an enclosure weatherproof when the receptacle is covered (plug not inserted, covers closed), and 15- and 20-ampere, 125- and 250-volt nonlocking receptacles there must be listed weather-resistant type; such a covered patio is classified as a damp, not wet, location.
NEC 2017 Section 406.9(A)NEC 2017 and 2020 — hermetic compressor OCPDvsNEC 2023 and 2026 — hermetic compressor OCPD
Under the 2017 and 2020 editions there is no next-size-up exception, so the 440.22(A) device may not exceed 175% of RLA (e.g., 52.5 A means a 50 A device), while the 2023 and 2026 editions (440.22(A) Exception No. 1) permit the next higher standard rating (60 A).
NEC 2017 Section 440.22(A), 440.32Overhead span up to 50 ft [225.6(A)(1)]vsOverhead span longer than 50 ft [225.6(A)(1)]
For 1000 volts or less, open individual conductors must be not smaller than 10 AWG copper for spans up to 50 ft, but not smaller than 8 AWG copper for longer spans unless supported by a messenger wire.
NEC 2017 Section 225.6(A)Key Terms
Authority Having Jurisdiction (AHJ) NEC 2017 Article 100 (Definitions)
Per NEC Article 100, an organization, office, or individual responsible for enforcing the requirements of a code or standard, or for approving equipment, materials, an installation, or a procedure; per 90.4 the AHJ has responsibility for interpreting the rules, approving equipment and materials, and granting special permission.
Continuous load NEC 2017 Article 100 — Continuous Load definition
Per NEC Article 100, a load where the maximum current is expected to continue for 3 hours or more.
Main bonding jumper NEC 2017 Article 100 (Definition: Bonding Jumper, Main)
Per NEC Article 100, the connection between the grounded circuit conductor and the equipment grounding conductor at the service; without it the effective ground-fault current path at the service is incomplete.
System bonding jumper NEC 2017 Article 100 (Definition: Bonding Jumper, System)
Per NEC Article 100, the connection between the grounded circuit conductor and the supply-side bonding jumper, the equipment grounding conductor, or both, at a separately derived system.
Tap conductor NEC 2017 Section 240.2
Per NEC 240.2, a conductor, other than a service conductor, that has overcurrent protection ahead of its point of supply exceeding the value permitted for similar conductors protected as described elsewhere in 240.4.
Objectionable current (250.6(D)) NEC 2017 Section 250.6(D)
Currents that introduce noise or data errors in electronic equipment shall NOT be considered the objectionable currents addressed in 250.6, so they do not justify the alterations permitted by 250.6(B).
Type IGS (Integrated Gas Spacer) cable NEC 2017 Section 326.104
Per 326.104, a cable whose conductors are solid aluminum rods laid parallel, consisting of one to nineteen 12.7 mm (½ in.) diameter rods, with a minimum conductor size of 250 kcmil and a maximum of 4750 kcmil.
Type AC cable bending radius NEC 2017 Section 320.24
Per 320.24, bends shall be made so the cable is not damaged and the radius of the curve of the inner edge of any bend shall be not less than five times the diameter of the Type AC cable.
Type MC cable (interlocked armor) bending radius NEC 2017 Section 330.24(B)
Per 330.24(B), the minimum bending radius for Type MC cable with interlocked-type armor or corrugated sheath is seven times the external diameter of the metallic sheath (e.g., 7 × 1.5 in. = 10.5 in.).
Class 1 remote-control and signaling circuit NEC 2017 Section 725.41(B)
Per Article 725 commentary, Class 1 circuits are not permitted to exceed 600 volts.
Grounded conductor identification, 6 AWG or smaller NEC 2017 Section 200.6(A)
Per 200.6(A), an insulated grounded conductor 6 AWG or smaller shall be identified by a continuous white outer finish, a continuous gray outer finish, or three continuous white or gray stripes along its entire length on other than green insulation.
120/240-Volt, Three-Phase, Four-Wire (Delta High Leg) system Ugly's Electrical References, 2023 ed., Common Electrical Distribution Systems, Page 13 (2020 ed.: Common Electrical Distribution Systems)
A distribution system whose B phase (high leg) must be colored orange or tagged, with caution noted for 208 volts orange to white.
Pull point (EMT bend limit) NEC 2017 Section 358.26
A conduit body counts as a pull point, and because bends are limited to 360° between pull points, each section between pull points may have up to 360° of bends.
Standard ampere ratings (Table 240.6(A)) NEC 2017 Table 240.6(A)
Standard ampere ratings for fuses and inverse time circuit breakers include values such as 45, 70, and 110 amperes; 85 amperes is not a standard rating listed in the table.
Dwelling service conductor 83% allowance [310.15(B)(7)] NEC 2017 Section 310.15(B)(7) with Table 310.15(B)(16)
For a 3-wire, single-phase dwelling unit service, service conductors are permitted to have an ampacity of 83% of the service rating, which permits 2/0 AWG THW copper for a 200-ampere service instead of 3/0 AWG.
Receptacle outlet unit load [220.14(I)] NEC 2017 Section 220.14(I)
Receptacle outlets shall be calculated at not less than 180 volt-amperes for each single or each multiple receptacle on one yoke, and a single piece of equipment consisting of a multiple receptacle of four or more receptacles at not less than 90 volt-amperes per receptacle.
Formulas to Know
Ohm's Law and power formulas
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 ((240)² ÷ 20 = 2880 W; (120)² ÷ 12 = 1200 W); R = E² ÷ P (14,400 ÷ 1200 = 12 Ω)Three-phase power and current (1.73 = √3 multiplier for the 120-degree phase relationship)
KW = (E × I × PF × 1.73) ÷ 1000 — example: (460 × 52 × 0.80 × 1.73) ÷ 1000 ≈ 33 kW; I = (KW × 1000) ÷ (E × PF × 1.73)Feeder with continuous and noncontinuous loads
Minimum conductor ampacity [215.2(A)(1)(a)] = noncontinuous load + 125% of continuous load — example: 120 A + (80 A × 1.25) = 220 A. Minimum feeder OCPD rating [215.3] = noncontinuous load + 125% of continuous load — example: 40 A + (80 A × 1.25) = 140 A.Motor conductor sizing (using Tables 430.247–430.250 values, not nameplate current)
Branch circuit [430.22(A)] = 125% × FLC — example: 125% × 65 A = 81.25 A. Feeder = 125% of largest motor FLC + sum of remaining motor FLCs. Controller-to-motor: wye-start delta-run not less than 72% of FLC; part-winding not less than 62.5% of FLC (50% × 1.25).Motor branch-circuit short-circuit/ground-fault protection maximums (Table 430.52)
Single-phase motor: nontime-delay fuse max 300% of FLC; dual-element time-delay fuse max 175% of FLC. Wound rotor: inverse time breaker max 150% of FLC. DC constant voltage: instantaneous trip breaker max 250% of FLC; AC polyphase/single-phase instantaneous trip 800%. Where the calculated value is not a standard size, 430.52(C)(1) Exception No. 1 permits the next standard size from Table 240.6(A) — example: 300% × 65 A = 195 A → 200 A fuse. Part-winding start induction motor (430.4): each winding connection protected at not more than one-half the value specified by 430.52.Generator output conductor ampacity (445.13)
Ampacity ≥ 115% of generator nameplate current — examples: 80 A × 1.15 = 92 A minimum; 200 A × 1.15 = 230 A minimumHermetic refrigerant motor-compressor branch circuit (no branch-circuit selection current marked)
Conductors [440.32] ≥ 125% × RLA (30 A × 1.25 = 37.5 A; 20 A × 1.25 = 25 A). OCPD [440.22(A)] not more than 175% × RLA (30 A × 1.75 = 52.5 A; 20 A × 1.75 = 35 A). If that device will not carry the starting current, the rating may be increased to not more than 225% of RLA (30 A × 2.25 = 67.5 A, so a 60 A device).Ampacity correction and adjustment
Correction factors apply where ambient temperature is other than the 30°C (86°F) base of Table 310.16; at 40°C (104°F) with 75°C conductors the correction factor is 0.88. Adjustment for 4 through 6 current-carrying conductors in a raceway = 80% of table value — example: 100 A × 0.80 = 80 A at 30°C ambient.Three-phase voltage drop (inductance negligible)
Vd = (1.73 × K × L × I) ÷ Cm — 1.73 replaces the factor of 2 used in single-phase calculationsPV interconnection 120 percent rule, load side of service disconnect [705.12(B)(3)(b)]
125% of power source output circuit current + rating of main overcurrent device shall not exceed 120% of busbar ampacity — example: 200 A busbar × 120% = 240 A; 240 A − 200 A main = 40 A maximum backfed PV breaker