Exam Cheat Sheet · Quick Reference
Oklahoma Limited Electrical Contractor
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
Conocimientos Generales
4 Q · 4%
a. Permits and Inspectionsb. Preservation of Structural Integrityc. Needs Analysis and Estimate
Conocimientos Generales de Electricidad
10 Q · 10%
a. Voltage, Current, and Resistance in Series, Parallel, and Combination Circuitsb. Power Used in a Circuitc. Power Lost (called Heat Lost) in Any Circuitd. Fundamental AC Theorye. Fundamental Three-phase AC Theoryf. Cost of Power Used in a Circuitg. Troubleshooting and Test Systemsh. National Electrical Codebooki. Definitions Used by the NECj. Temporary Wiringk. Cranes and Hoistsl. Elevators and Escalators
Requisitos de Instalación Eléctrica
10 Q · 10%
a. Approved Methods of Installation of Electrical Equipmentb. Approved Methods of Installation of Electrical Equipment in Excess of 600 volts
Servicios, Alimentadores y Circuitos Ramales
10 Q · 10%
a. Servicesb. Voltage Drop for Branch Circuits or Feedersc. Services in Excess of 600 voltsd. Feederse. Outside Branch Circuits and Feedersf. Branch Circuitsg. Space-heating, Snow-melting, and Pipeheating Circuitsh. Air-conditioning and Refrigeration Equipment
Protección contra Sobrecorriente
9 Q · 9%
a. NEC Overcurrent Protection Requirement
Puesta a Tierra y Unión
10 Q · 10%
a. General Requirementsb. Required Sizes of Grounding Electrode Conductorsc. Required Sizes of Equipment Grounding Conductors
Conductores y Cables
8 Q · 8%
a. Underground Conductors and Cablesb. Vertical Installationsc. Selecting Conductorsd. Armored Cable, Type ACe. Metal-clad Cable, Type MCf. Nonmetallic-sheathed Cable, Types NM, NMC, NMSg. Service Entrance Cables, Types SE and USEh. Underground Feeder and Branch Circuit Cable, Type UFi. Mineral Insulated, Type MIj. Flat Cable Assemblies, Type FC, and Flat Conductor Cable, Type FCCk. Medium Voltage Cable, Type MV
Canaletas y Cajas
10 Q · 10%
a. General Raceway Requirementsb. General Box Requirementsc. Pull Boxesd. Conduit Fittingse. Type RMC (Rigid Metal Conduit)f. Type EMT (Electric Metallic Conduit)g. Type IMC (Intermediate Metal Conduit)h. Type RNC (Rigid Nonmetallic Conduit)i. Type FMC (Flexible Metal Conduit)j. Type LFMC (Liquid-tight Flexible Metal Conduit)k. Type FMT (Flexible Metallic Tubing)l. Type HDPE (High-density Polyethylene Conduit)
+10 more
Ocupaciones y Equipos Especiales
7 Q · 7%
a. Wiring in Class I, II, and III Hazardous Locationsb. Wiring in Commercial Garages and Fuel Dispensing Facilitiesc. Wiring in Bulk Storage Plants, Paint, and Spray Areasd. Special Occupanciese. Wiring in Health Facilities and Places of Assemblyf. Wiring of Mobile Home, Mobile Home Parks, RVs, and RV Parksg. Wiring of Floating Buildingsh. Wiring to Swimming Pools, Fountains, and Hot Tubs
Baja Tensión, Alarmas, Sistemas de Señalización y Comunicaciones
6 Q · 6%
a. Remote Control or Signaling Circuitsb. Communication Circuitsc. Equipment Operating at 50 volts or Lessd. Fiber Opticse. Photovoltaicsf. Remote Controlsg. Fire Alarmsh. Circuit Wiring for an Emergency Systemi. Communications Systems Wiring
Iluminación y Letreros
4 Q · 4%
a. Fixture Installationb. Fixture Groundingc. Fixture Wiringd. Fluorescent Fixturese. Fixture Construction Requirementsf. Recessed Fixturesg. Lighting Systems that Operate at Less Than 30 voltsh. Neon Lighting and Electric Signs
Seguridad
10 Q · 10%
a. Job Site Sanitationb. Responsibility for Providing Personal Protective Equipmentc. Excavation Safetyd. Emergency Action Planse. Safety Training Requirementsf. Ventilationg. First Aid Kit Requirementsh. Use of Personal Protective Equipmenti. Signs, Signals, and Barricadesj. Tools and Equipmentk. Laddersl. Workplace Illumination
+6 more
Motores y Transformadores
2 Q · 2%
a. Motors Used in Dwellingsb. Motor Branch Circuits in Industrial and Commercial Locationsc. Feeder Transformersd. Use of Transformers
Key Distinctions
Series Circuit Total ResistancevsParallel Circuit Total Resistance
In a series circuit, total resistance equals the sum of all individual resistances (RT = R1+R2+R3…), whereas in a parallel circuit the total resistance is always less than the resistance of any individual branch.
Ugly's Electrical References, Series Circuits, Book Page 3Dwelling Unit Lighting Unit Load (3 VA/sq ft)vsRetail Occupancy Lighting Unit Load (1.9 VA/sq ft)
NEC 220.41 requires a minimum of 3 VA per square foot for dwelling units, while NEC Table 220.42(A) assigns only 1.9 VA per square foot for retail occupancies.
NEC 220.41Small-Appliance Branch Circuit Load (1500 VA)vsReceptacle Outlet Load (180 VA)
Each 2-wire small-appliance branch circuit in a dwelling unit is calculated at 1500 VA per NEC 220.52(A), whereas each single or multiple receptacle on one yoke is calculated at a minimum of 180 VA per NEC 220.14(I).
NEC 220.52(A)Temporary Holiday Decorative Lighting (90 days max)vsTemporary Construction Site Wiring (project duration)
NEC 590.3(B) limits temporary holiday decorative lighting to 90 days, while temporary construction wiring is permitted for the duration of the construction, remodeling, maintenance, or demolition activity.
NEC Article 590.3(B)Crane Power Supply Conductors – Largest Motor (100%)vsCrane Power Supply Conductors – Next Largest Motor (50%)
Per NEC 610.14(E)(2), the minimum ampacity for crane power supply conductors is 100% of the largest motor's nameplate FLA plus only 50% of the next largest motor's nameplate FLA.
NEC Article 610.14(E)(2)Fixed Electric Space-Heating Load (100%)vsCommercial Kitchen Equipment Load (demand factor allowed)
NEC 220.51 requires fixed electric space-heating loads to be calculated at 100% of connected load with no demand factor, whereas NEC Table 220.56 permits a 65% demand factor for 6 or more units of commercial kitchen equipment.
NEC 220.51Non-Dwelling Receptacle Demand: First 10 kVA (100%)vsNon-Dwelling Receptacle Demand: Remainder over 10 kVA (50%)
Per NEC Table 220.47, the first 10 kVA of non-dwelling receptacle load is taken at 100%, while any load in excess of 10 kVA is reduced to 50% for the calculated demand.
NEC Table 220.47Elevator Feeder Demand Factor – 1 Elevator (1.00)vsElevator Feeder Demand Factor – 5 Elevators (0.82)
Per NEC Table 620.14, a single elevator on a feeder requires a demand factor of 1.00 (no reduction), while five elevators on a single feeder use a reduced demand factor of 0.82.
NEC Table 620.14Temporary Wiring – Cable on Ground (prohibited)vsTemporary Wiring – GFCI at Receptacles (required)
NEC 590.4(J) prohibits cable assemblies and flexible cords used as branch circuits or feeders from being installed on the floor or ground, while NEC 590.6(A)(1) separately requires GFCI protection for all 125V single-phase 15-, 20-, and 30-A receptacles not part of permanent wiring.
NEC Article 590.4(J)Rounding: Decimal < 0.5 (drop)vsRounding: Decimal ≥ 0.5 (round up)
Per NEC 220.5(B), load calculation results in amperes may be rounded to the nearest whole ampere, dropping fractions smaller than 0.5 and rounding up fractions of 0.5 or greater.
NEC 220.5(B)Key Terms
Nominal System Voltage (NEC 220.5(A)) NEC 220.5(A)
NEC 220.5(A) lists standard nominal voltages for branch-circuit and feeder load calculations as 120, 120/240, 208Y/120, 240, 347, 480Y/277, 480, 600Y/347, and 600 volts; '277/480' is not a listed designation.
Calculated Floor Area – Dwelling Unit (NEC 220.5(C)) NEC 220.5(C)
Per NEC 220.5(C), the floor area used for dwelling unit load calculations shall NOT include open porches or unfinished areas not adaptable for future use as a habitable room or occupiable space.
Minimum Dwelling Unit Lighting Load (NEC 220.41) NEC 220.41
Per NEC 220.41, one-family, two-family, and multifamily dwellings must use a minimum unit load of 3 volt-amperes per square foot for load calculations.
Small-Appliance Branch Circuit Load (NEC 220.52(A)) NEC 220.52(A)
Per NEC 220.52(A), each 2-wire small-appliance branch circuit in a dwelling unit shall be calculated at 1500 volt-amperes.
Receptacle Outlet Load (NEC 220.14(I)) NEC 220.14(I)
Per NEC 220.14(I), each single or multiple receptacle on one yoke shall be calculated at not less than 180 volt-amperes for branch-circuit load purposes.
Existing Installation Maximum Demand Method (NEC 220.87) NEC 220.87
Per NEC 220.87, when using a minimum 1-year metered demand data record for existing installations, the maximum demand multiplied by 125% plus the new load must not exceed the feeder ampacity or service rating.
Commercial Kitchen Equipment Demand Factor (NEC Table 220.56) NEC Table 220.56
Per NEC Table 220.56, a demand factor of 65% is permitted for 6 or more units of commercial electric cooking equipment, but the calculated load shall never be less than the sum of the two largest individual equipment loads.
Fixed Electric Space-Heating Load (NEC 220.51) NEC 220.51
Per NEC 220.51, fixed electric space-heating loads shall be calculated at 100% of total connected load for feeder and service calculations, with an exception only if the AHJ permits reduced loading for intermittent operation.
Temporary Wiring – Holiday Lighting Duration (NEC 590.3(B)) NEC Article 590.3(B)
Per NEC 590.3(B), temporary electric power and lighting for holiday decorative lighting and similar purposes is permitted for a period not to exceed 90 days.
Temporary Wiring – GFCI Requirement (NEC 590.6(A)(1)) NEC Article 590.6(A)(1)
Per NEC 590.6(A)(1), all 125-volt, single-phase, 15-, 20-, and 30-ampere receptacle outlets not part of permanent wiring and in use by personnel must have ground-fault circuit-interrupter protection.
Elevator Supply Voltage Limit (NEC 620.3) NEC Article 620.3
Per NEC 620.3, the supply voltage for elevators, dumbwaiters, escalators, and moving walks shall not exceed 300 volts between conductors unless specific exceptions in 620.3(A)–(C) apply.
Crane Working Space Clearance (NEC 610.57) NEC Article 610.57
Per NEC 610.57, the minimum working space clearance in the direction of access to energized live parts on a crane that may require examination, adjustment, or maintenance while energized is 750 mm (2½ ft).
Parallel Circuit Total Resistance Ugly's Electrical References, Parallel Circuits, Book Page 5
In a parallel circuit, the total resistance is always less than the resistance of any single individual branch, regardless of the number of branches.
Series Circuit Total Resistance Ugly's Electrical References, Series Circuits, Book Page 3
In a series circuit, total resistance equals the arithmetic sum of all individual resistances (RT = R1 + R2 + R3 + …).
Luminaire Outlet Load (NEC 220.14(D)) NEC 220.14(D)
Per NEC 220.14(D), an outlet supplying a luminaire shall be calculated based on the maximum volt-ampere rating of the equipment and lamps for which the luminaire is rated.
Elevator Feeder Demand Factor (NEC Table 620.14) NEC Table 620.14
Per NEC Table 620.14, demand factors ranging from 1.00 (1 elevator) down to 0.72 (10 or more elevators) are applied to feeder conductor sizing based on a 50% duty cycle assumption.
Formulas to Know
General Lighting Load (any occupancy)
Lighting Load (VA) = Floor Area (sq ft) × Unit Load (VA/sq ft)Series Circuit Total Resistance
RT = R1 + R2 + R3 + … (sum of all resistors)Three-Phase Kilowatts
KW = (E × I × PF × 1.73) / 1000Three-Phase Amperes from Kilowatts
I = (KW × 1000) / (E × PF × 1.73)Ohm's Law – Resistance from Power and Voltage
R = E² / P (also R = E / I)Operating Cost
Cost ($) = (Watts × Hours) / 1000 × Rate ($/kWh)Non-Dwelling Receptacle Demand Load
Demand (VA) = (First 10,000 VA × 100%) + (Remainder over 10,000 VA × 50%)Crane Power Supply Minimum Ampacity (Multiple Motors)
Ampacity = 100% × (Largest motor FLA) + 50% × (Next largest motor FLA)Existing Installation Load Check (NEC 220.87)
Maximum Demand × 1.25 + New Load ≤ Feeder Ampacity (or Service Rating)