Exam Cheat Sheet · Quick Reference
Oklahoma Unlimited Electrical Journeyman
Oklahoma · PSI Services Contractor
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
70%
Exam time
240 min
Administered by
PSI Services Contractor
Format
Reference materials allowed
Oklahoma State Portion 100 questions
General Knowledge
4 Q · 4%
NEC Article 90 scope, purpose, and code arrangementNEC mandatory vs. permissive rules and explanatory material (shall/shall not vs. shall be permitted)Authority having jurisdiction (AHJ) enforcement and special permissionField terms versus NEC terms (common trade names mapped to NEC article references)Electrical schematic symbols and wiring diagram notationU.S. and metric units of measurement and conversion (linear, area, weight, capacity)Metric prefixes and metric designator/trade sizes for conduitApplied math for electricians: fractions, decimals, equations, geometry of the circle, and trigonometric functions
General Electrical Knowledge
10 Q · 10%
Ohm's Law and power formulas (P, E, I, R relationships)Series, parallel, and combination circuit calculationsElectrical formulas for AC/DC amperes, horsepower, kilowatts, and kVAConductor ampacity tables and temperature ratings (NEC Table 310.16/310.17)Ampacity correction and adjustment factors (ambient temperature and number of conductors)Voltage drop calculations for single-phase and three-phase circuitsConductor types, insulation designations, and application provisionsGrounded conductor identification and use (color coding, terminal marking)
Electrical Installation Requirements
10 Q · 10%
Branch-circuit ratings, conductor sizing, and overcurrent protection requirementsGFCI protection requirements by location and occupancy typeAFCI protection requirements by occupancy and installation typeReceptacle outlet placement and spacing requirements for dwelling and non-dwelling occupanciesLoad calculations using demand factors for lighting, appliances, cooking equipment, and dryersUnderground installation minimum cover requirements by wiring methodWorking space clearances and live-part clearance requirements at electrical equipmentOutside branch circuit and feeder clearances, disconnecting means, and support requirements
Services, Feeders, and Branch Circuits
10 Q · 10%
Service conductor sizing, ampacity, and minimum size requirements (Articles 230, 215)Branch-circuit, feeder, and service load calculations using demand factors (Article 220)Service disconnecting means: location, rating, number, and grouping requirementsOvercurrent protection for services and feeders, including ground-fault protection of equipmentOverhead service conductor clearances: above roofs, from grade, and from building openingsVoltage drop calculations for single-phase and three-phase circuitsMotor branch circuit and feeder conductor sizing and overcurrent protectionOutside branch circuit and feeder requirements: clearances, disconnecting means, and wiring methods
Overcurrent Protection
9 Q · 9%
Protection of conductors by overcurrent device ratings and ampacity (NEC 240.4)Standard ampere ratings for fuses and circuit breakers (NEC 240.6 Table)Location of overcurrent protective devices in circuits, including tap conductor rules (NEC 240.21)Circuit breaker requirements: marking, ratings, arc energy reduction, and series ratings (NEC 240.80–240.87)Fuse types and requirements: plug fuses, cartridge fuses, Type S fuses, and fuseholder rules (NEC 240.50–240.61)Motor branch-circuit overcurrent protective device maximum ratings and settings (NEC 430.52 / Ugly's Table)Short-circuit current calculations and component protection using let-through chartsOvercurrent protection for systems rated over 1000 volts: circuit breakers, power fuses, and feeder requirements (Article 245)
Grounding and Bonding
10 Q · 10%
Grounding electrode types, specifications, and installation requirements (NEC 250.52–250.54)Grounding electrode conductor sizing using Table 250.66Equipment grounding conductor types, sizing, and identification (NEC 250.118–250.122)Main bonding jumper and system bonding jumper installation and sizingSupply-side bonding jumper sizing using Table 250.102(C)(1)Bonding of piping systems, structural metal, and service equipment (NEC 250.92–250.104)Grounding of separately derived AC systems (NEC 250.30)General requirements for grounded vs. ungrounded systems and effective ground-fault current path
Conductors and Cables
7 Q · 7%
Conductor ampacity tables (raceway, cable, free air, and direct burial installations)Ampacity correction and adjustment factors (ambient temperature and number of current-carrying conductors)Conductor insulation types, temperature ratings, and application provisionsCable type uses permitted and uses not permitted (NM, MC, AC, SE, USE, UF, MI, TC, ITC, MV, and specialty types)Securing, supporting, and bending radius requirements for cable typesConductor sizing, materials, and minimum size requirements (copper, aluminum, copper-clad aluminum)Conductor fill calculations and maximum number of conductors in conduit or tubingMedium voltage (Type MV) cable construction, shielding, insulation levels, and ampacity
Raceways and Boxes
8 Q · 8%
Conduit fill calculations and conductor count limits (Chapter 9, Table 1)Securing and supporting requirements for each raceway typeUses permitted and uses not permitted for metallic conduit systems (RMC, IMC, EMT, FMC, LFMC, FMT)Uses permitted and uses not permitted for nonmetallic conduit systems (PVC, RTRC, HDPE, NUCC, ENT, LFNC)Box fill calculations and volume allowances (Article 314)Pull and junction box sizing for straight, angle, and U pullsBox and enclosure support methods and mounting requirementsCable tray types, fill limits, ampacity, and grounding requirements
Special Occupancies and Equipment
10 Q · 10%
Hazardous location classification (Class I, II, III; Divisions 1 and 2; Zone 0/1/2 and Zone 20/21/22)Wiring methods and sealing requirements in hazardous classified locationsProtection techniques for hazardous locations (explosionproof, intrinsically safe, pressurized, dusttight, encapsulation)Health care facility essential electrical systems (Type 1 and Type 2 EES, life safety and critical branches)Patient care space wiring, grounding, bonding, and receptacle requirementsSpecial occupancy area classification (commercial garages, aircraft hangars, motor fuel dispensing, bulk storage, spray application)Electrical requirements for mobile homes, manufactured homes, recreational vehicles, and park trailersElevators, escalators, cranes, and hoists electrical installation requirements
Low Voltage, Alarms, Signaling Systems, and Communications
6 Q · 6%
Fire alarm circuit wiring methods and installation requirements (NPLFA and PLFA)Power-limited fire alarm (PLFA) cable types, listings, and substitutionsCircuit separation and mixing rules for Class 2, Class 3, and communications circuitsEmergency system wiring, transfer equipment, and alternate power sourcesGrounding and bonding of communications, antenna, and broadband systemsCommunications cable types and installation by building location (plenum, riser, general-purpose)Legally required standby and critical operations power system requirementsLow-voltage lighting system voltage limits, isolation, and branch circuit requirements
Lighting and Signs
4 Q · 4%
Luminaire location requirements (wet, damp, corrosive, bathtub/shower zones, clothes closets)Luminaire support methods and weight limitationsGrounding and bonding of luminaires and lighting equipmentWiring methods and conductor requirements within luminairesRecessed luminaire installation (Type IC, thermal protection, clearances from insulation and combustibles)Lighting track installation, construction, and restrictionsElectric signs and outline lighting branch circuits, disconnecting means, and groundingEnergy cost calculations and lamp efficiency comparisons
Safety
10 Q · 10%
Lockout/tagout and electrically safe work condition proceduresPersonal protective equipment (PPE) selection and requirementsElectrical shock protection boundaries and approach limitsArc-flash hazard identification and equipment labelingFall protection systems and requirementsFire protection, prevention, and flammable liquid storageConfined space entry requirements and permit proceduresLadder and stairway safety requirements
Motors and Transformers
2 Q · 2%
Motor branch-circuit conductor sizing (125% rule, NEC 430.22)Branch-circuit short-circuit and ground-fault protective device selection (NEC Table 430.52)Motor overload protection requirements and trip current percentages (NEC 430.32)Motor disconnecting means type, location, and rating requirements (NEC 430.102–430.110)Motor feeder conductor sizing and feeder overcurrent protection (NEC 430.24, 430.62)Transformer overcurrent protection sizing for primary and secondary (NEC 450.3, Tables 450.3(A) and 450.3(B))Transformer calculations: kVA sizing, primary/secondary current, turns ratio, and short-circuit currentHermetic refrigerant motor-compressor branch-circuit and overload protection requirements (NEC Article 440)Delta and wye transformer connections (line vs phase voltage and current, neutral current, balancing)
Key Distinctions
Class I LocationvsClass II Location
Class I is hazardous due to flammable gases or vapors under normal operating conditions, while Class II is hazardous due to combustible dusts.
NEC 500.5(B)(1)Class II LocationvsClass III Location
Class II involves combustible dusts suspended in air in ignitible quantities, while Class III involves easily ignitible fibers or flyings that are not normally suspended in air in ignitible concentrations.
NEC 500.5(D)(1)Class I, Division 1vsClass I, Division 2
Division 1 locations have ignitible concentrations of flammable gases/vapors present under normal operating conditions; explosionproof equipment is permitted in both divisions.
NEC 500.5(B)(1)Mandatory NEC RulesvsInformational Notes
Mandatory rules use 'shall' or 'shall not' and are enforceable, while Informational Notes are included for informational purposes only and are NOT enforceable.
NEC 90.5(A)NEC Chapters 1–4vsNEC Chapters 5, 6, and 7
Chapters 1–4 apply generally to all installations, while Chapters 5, 6, and 7 apply only to special occupancies, special equipment, or other special conditions.
NEC 90.3NEC Chapters 1–7vsNEC Chapter 8
Chapters 1–7 apply generally (with varying scope), while Chapter 8 (Communications Systems) is NOT subject to Chapters 1–7 except where specifically referenced within Chapter 8.
NEC 90.3Emergency System Response Time (NEC 700.12)vsEmergency Power Source Minimum Duration (NEC 700.12(C))
Emergency power must become available within 10 seconds of normal supply failure, while the source must sustain the total load for a minimum of 2 hours.
NEC 700.12Motor Branch-Circuit Conductor Ampacity (430.22(A))vsMotor Disconnect Ampere Rating (430.110(A))
Branch-circuit conductors must be sized at 125% of motor full-load current, while the disconnecting means must have an ampere rating of at least 115% of motor nameplate current.
NEC 430.22(A)Plug Fuses ≤15 AvsPlug Fuses >15 A
Fuses rated 15 amperes or lower are identified by a hexagonal window, cap, or prominent part to physically distinguish them from higher-rated fuses.
NEC 2023, Section 240.50(C)Solid Conductors in RacewaysvsStranded Conductors in Raceways
Conductors 8 AWG and larger installed in raceways must be stranded; smaller conductors may be solid unless otherwise required.
NEC 2023, Section 310.3(C)MV Cable Ampacity Tables (Air Ambient)vsGeneral Wiring Ampacity Tables (310.16/310.17 Ambient)
Ampacity tables for medium-voltage cables in air are based on a 40°C ambient temperature, while the standard general-wiring ampacity tables use a 30°C ambient.
NEC 2023, Section 315.60(E)Group E (Class II)vsGroup A (Class I)
Group E atmospheres contain combustible metal dusts such as aluminum and magnesium, while Group A is specifically acetylene gas.
NEC 500.6(B)(1)Key Terms
Purpose of the NEC (NEC 90.1(A)) NEC 90.2(A)
The practical safeguarding of persons and property from hazards arising from the use of electricity; it is not a design specification or instruction manual.
Authority Having Jurisdiction (AHJ) — NEC 90.4 NEC 90.4(B)
The party responsible for making interpretations of NEC rules, approving equipment and materials, and granting special permissions under the Code.
Mandatory Rule Language — NEC 90.5(A) NEC 90.5(A)
Rules characterized by 'shall' or 'shall not' that identify actions specifically required or prohibited by the Code.
NEC Scope Exclusions — NEC 90.2(B) NEC 90.2(D)
The NEC 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.
Emergency System Maximum Response Time — NEC 700.12 NEC 700.12
Emergency lighting and/or power must be available within the time required for the application but not to exceed 10 seconds after failure of the normal supply.
Emergency Power Source Minimum Duration — NEC 700.12(C) NEC 700.12(C)
The emergency power source must supply and maintain the total load for no less than 2 hours of full-demand operation.
Emergency Feeder Fire Rating — NEC 700.10(D)(2) NEC 700.10(D)(2)
Feeder-circuit wiring for emergency systems in assembly occupancies (1,000+ persons) or buildings above 75 ft must be protected by a listed electrical circuit protective system with a minimum 2-hour fire rating.
Service Disconnect Maximum Count — NEC 230.71(B) NEC 230.71(B)
A single service is permitted a maximum of six disconnecting means.
Single-Family Dwelling Service Rating — NEC 230.79(C) NEC 230.79(C)
Service equipment for a one-family dwelling shall have a rating of not less than 100 amperes, 3-wire.
NPT Thread Engagement — NEC 500.8(E)(1) NEC 500.8(E)(1)
NPT-threaded entries into explosionproof equipment must be made up with at least five threads fully engaged.
Explosionproof Equipment — NEC 500.7(A) NEC 500.7(A)
A protection technique permitted for electrical equipment in Class I, Division 1 or Division 2 hazardous locations.
Equipment Grounding Conductor (EGC) in Flexible Cord — NEC 250.122(E) NEC 250.122(E)
The EGC in a flexible cord shall not be smaller than 18 AWG copper and shall not be smaller than the circuit conductors; on a 15 A circuit (14 AWG conductors), the EGC must be at least 14 AWG.
Grounding Electrode Conductor Size — NEC Table 250.66 NEC Table 250.66
For 4/0 AWG copper service entrance conductors, the minimum grounding electrode conductor is 2 AWG copper.
Group A — Class I Hazardous Material (NEC 500.6(A)(1)) Article 500.6(A)(1)
Group A is specifically acetylene, the most hazardous Class I gas classification.
Class III, Division 1 — NEC 500.5(D)(1) NEC 500.5(D)(1)
Locations where easily ignitible fibers or materials producing combustible flyings are handled, manufactured, or used; fibers are not normally suspended in air in ignitible quantities but can collect around machinery.
Storage Battery Emergency Illumination Voltage — NEC 700.12(C)(4) NEC 700.12(C)(4)
Storage batteries supplying emergency illumination must maintain load voltage at no less than 87.5% of nominal voltage for a minimum period of 1½ hours.
Formulas to Know
Motor Branch-Circuit Conductor Ampacity
Conductor ampacity ≥ 1.25 × Motor Full-Load Current (FLC)Motor Disconnect Minimum Ampere Rating
Disconnect rating ≥ 1.15 × Motor Nameplate CurrentGrounding Electrode Conductor Size
Use NEC Table 250.66 based on size of largest service-entrance conductor (e.g., 4/0 AWG Cu service → 2 AWG Cu GEC)Emergency System Available Time
Available time ≤ 10 seconds after normal supply failureEmergency Power Source Minimum Run Duration
Duration ≥ 2 hours at full load (≥ 1.5 hours for storage battery emergency illumination)Single-Family Dwelling Minimum Service Size
Service rating ≥ 100 A, 3-wire