Exam Cheat Sheet · Quick Reference
Louisiana Electrical Statewide
Louisiana · 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
Louisiana State Portion 100 questions
General Knowledge
4 Q · 4%
Ohm's Law formulas and calculations (voltage, current, resistance, power)Series, parallel, and combination circuit analysisElectrical formulas for AC and DC systems (amperes, kilowatts, kVA, horsepower)Kirchhoff's Current and Voltage LawsThree-phase and single-phase power calculations and distribution systemsImpedance, inductive reactance, and capacitive reactanceNEC Article 90 scope, purpose, code arrangement, and enforcementSelecting and using test instruments (multimeters, clamp-on ammeters, non-contact voltage testers)
General Electrical Knowledge
10 Q · 10%
Ohm's Law formulas and calculations (voltage, current, resistance, power)Series, parallel, and combination circuit analysisVoltage drop calculations for single-phase and three-phase circuitsElectrical formulas for amperes, kilowatts, kVA, and horsepower (DC, single-phase, three-phase)Impedance, reactance, inductance, and capacitance in AC circuitsPower factor, apparent power, and power factor correctionCommon electrical distribution systems and conductor color codingNEC scope, arrangement, and mandatory vs. permissive rule language
Electrical Installation Requirements
10 Q · 10%
Branch circuit ratings, types, and voltage limitationsGrounding and bonding requirements for electrical systems and equipmentOvercurrent protection sizing and device placementService entrance conductor sizing, installation, and clearancesLoad calculations for branch circuits, feeders, and servicesWiring methods and raceway selection (EMT, RMC, IMC, PVC, FMC, LFMC)Cable assembly installation requirements (NM, MC, AC, SE/USE)GFCI and AFCI protection requirements by location and occupancy
Services, Feeders, and Branch Circuits
10 Q · 10%
Branch-circuit load calculations for dwelling and non-dwelling occupanciesFeeder and service load calculations including demand factorsGFCI and AFCI protection requirements by location and occupancy typeService conductor sizing, ampacity, and wiring methodsOvercurrent protection: ratings, location, and tap conductor rulesGrounding electrode system, conductor sizing, and bonding requirementsConductor ampacity correction and adjustment factorsVoltage drop calculations for branch circuits and feeders
Overcurrent Protection
9 Q · 9%
Standard ampere ratings for fuses and circuit breakers (Table 240.6)Protection of conductors by overcurrent device ratings (240.4 small conductor rules and next-size-up provisions)Location of overcurrent protective devices in circuits including feeder and transformer secondary tap rules (240.21)Motor branch-circuit short-circuit and ground-fault protection ratings and device selection (Table 430.52)Motor overload protection requirements and trip current percentages (430.32)Transformer overcurrent protection requirements (Tables 450.3(A) and 450.3(B))Fire pump overcurrent protection special rules (no overload protection, locked-rotor carry requirements)Overcurrent protection for systems over 1000 volts including high-voltage fuses and circuit breakers (Article 245)
Grounding and Bonding
10 Q · 10%
Grounding electrode system types and installation requirements (NEC 250.52–250.54)Sizing of grounding electrode conductors for AC systems (Table 250.66)Equipment grounding conductor types, sizing, and identification (NEC 250.118–250.122)Main bonding jumper and system bonding jumper requirements (NEC 250.28)Sizing of grounded conductor, main bonding jumper, and supply-side bonding jumper (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)Identification and use of grounded conductors (NEC Article 200)
Conductors and Cables
8 Q · 8%
Conductor insulation types, temperature ratings, and application provisions (Table 310.4)Ampacity tables for conductors in raceways, cables, and free air (Tables 310.16–310.21)Ampacity correction factors for ambient temperature and adjustment factors for more than three current-carrying conductorsConductor material, minimum size, stranding, and parallel installation requirementsCable type uses permitted and uses not permitted (NM, MC, AC, MI, SE/USE, UF, TC, ITC, FC, FCC, MV)Securing, supporting, and bending radius requirements for cable typesGrounded conductor identification methods and color coding (Article 200)Voltage drop calculations and conductor sizing for single-phase and three-phase circuits
Raceways and Boxes
7 Q · 7%
Conduit fill calculations and conductor count limits by raceway typeSecuring and support intervals for conduit and tubing typesPermitted and prohibited uses for each raceway type (RMC, IMC, EMT, FMC, LFMC, PVC, ENT, LFNC, FMT, HDPE, RTRC, NUCC)Box fill calculations and minimum box volume requirementsPull and junction box sizing for conductors 4 AWG and largerUnderground installation requirements and minimum cover depths for racewaysProtection of raceways and cables against physical damageGrounding and bonding requirements for metal raceways and boxes
Special Occupancies and Equipment (Including Swimming Pools)
10 Q · 10%
Swimming pool bonding and equipotential bonding requirementsGFCI and SPGFCI protection for pools, spas, fountains, and similar installationsUnderwater luminaires and junction box installation requirementsHazardous location classification (Class I, II, III; Division 1 and 2; Zone 0/1/2)Wiring methods and sealing requirements for hazardous classified locationsHealth care facility essential electrical systems and patient care space wiringSpecial occupancy wiring requirements for garages, marinas, motor fuel dispensing, and agricultural buildingsElectrical installations for elevators, fire pumps, cranes, and electric vehicle supply equipment
Low Voltage, Alarms, Signaling Systems, and Communications
2 Q · 2%
Fire alarm circuit wiring methods and cable types (NPLFA and PLFA)Power sources and branch circuit requirements for fire alarm systemsSeparation and mixing rules for low-voltage circuit conductors with other systemsClass 2 and Class 3 power-limited circuit installation and power source requirementsCommunications cable types, applications, and substitution hierarchyGrounding and bonding of communications system entrance cablesOptical fiber cable types, applications, and installation in buildingsClass 4 fault-managed power systems installation and listing requirements
Lighting and Signs
10 Q · 10%
Luminaire installation requirements by location (wet, damp, corrosive, closets, bathtub/shower zones)Recessed luminaire clearances, thermal protection, and Type IC vs. non-IC classificationsLighting track installation, construction requirements, and prohibited locationsElectric sign and outline lighting disconnecting means, branch circuit requirements, and grounding/bondingNeon secondary-circuit wiring requirements (1000 volts or less and over 1000 volts)Low-voltage lighting system voltage limitations, isolation, and branch circuit requirementsFixture wire types, ampacity, minimum size, and permitted usesStage and theater lighting wiring methods, dimmers, and equipment grounding
Safety
4 Q · 4%
Lockout/tagout procedures and establishing an electrically safe work conditionElectrical shock protection boundaries (limited and restricted approach)Arc-flash hazard assessment and PPE categories by arc ratingGround-fault circuit interrupter (GFCI) and assured equipment grounding conductor program requirementsWorking clearances and minimum depth of clear working space at electrical equipmentPersonal protective equipment for electrical work (rubber insulating gloves, sleeves, blankets, and classes)Fall protection systems for electrical construction work (personal fall arrest, positioning, guardrail)Ladder and stairway safety requirements on construction sites
Motors and Transformers
6 Q · 6%
Motor branch-circuit conductor sizing (125% of full-load current rule)Motor branch-circuit short-circuit and ground-fault protective device ratings (Table 430.52)Motor overload protection requirements and trip current percentages (430.32)Motor disconnecting means types, ratings, and location requirements (430.109/430.110)Motor feeder conductor sizing and overcurrent protection for multiple motors (430.24/430.62)Transformer overcurrent protection ratings for primary and secondary (Article 450/Table 450.3)Transformer sizing, kVA calculations, and primary/secondary current calculationsMotor controller ratings, marking requirements, and motor control centers (430.8/430.83/430.98)
Key Distinctions
Series circuitvsParallel circuit
In a series circuit total resistance is the sum of the resistances and the current is the same in every part (IT = I1 = I2 = I3), while in a parallel circuit the voltage is the same across every branch (ET = E1 = E2 = E3) and total current is the sum of the branch currents.
Ugly's Electrical References 2020, Series Circuits, Book Page 3Ammeter (meter in series)vsVoltmeter (meter in parallel)
An ammeter is inserted in series so full circuit current flows through it and must have very low internal resistance, while a voltmeter is connected across (in parallel with) a component to read potential difference and has very high internal resistance so it draws negligible current.
Raceway-supported enclosure WITHOUT a device or luminaire — 314.23(E)vsRaceway-supported enclosure WITH a device or supporting a luminaire — 314.23(F)
Under 314.23(E) an enclosure containing only splicing devices and supported by entering raceways shall not exceed 1650 cm³ (100 in.³), whereas under 314.23(F) an enclosure containing a device or supporting a luminaire/lampholder must be supported by two or more wrenchtight conduits each secured within 450 mm (18 in.) of the enclosure (tighter than the 900 mm/3 ft rule applying under 314.23(E)).
NEC 2023 Section 314.23(E)Portable power feeder cable Types G, SHD-PCG, SHD-CGCvsPortable power feeder cable Types SH, SHD, SHD-GC
Per 400.50, Types G, SHD-PCG, and SHD-CGC shall be used only from 2000 to 5000 volts, while Types SH, SHD, and SHD-GC are permitted from 2000 to 25,000 volts.
NEC 2023 Section 400.50Type SJ flexible cordvsType SO flexible cord
Per Table 400.4, Type SJ (junior hard service) is rated for pendant or portable use in damp locations at hard usage, while Type SO (hard service) is rated for extra-hard usage at a maximum 600 volts.
NEC 2023 Table 400.4Type SPT-1 flexible cordvsType SO flexible cord
Type SPT-1 is rated 300 volts maximum and is suitable for pendant/portable use in damp locations at not hard (light) usage, while Type SO is rated 600 volts and extra-hard usage.
NEC 2023 Table 400.4Office furnishing flexible power supply cord — 605.9(A)vsLighting accessory cord connection — 605.6(B)(1)
The freestanding office-furnishing power supply cord must be extra-hard usage, 12 AWG or larger with an insulated EGC, and shall not exceed 600 mm (2 ft), while the 2.7 m (9 ft) limit applies only to lighting accessory cord connections.
NEC 2023 Section 605.9(A)Direct-buried cables/conductors — minimum covervsRigid metal conduit or IMC — minimum cover
Per Table 300.5(A), direct-buried cables or conductors in all locations not otherwise specified require 600 mm (24 in.) of cover, while RMC or IMC requires only 150 mm (6 in.).
NEC 2023 Table 300.5(A)Continuous loadvsNoncontinuous load
Continuous load is multiplied by 125 percent when sizing the branch-circuit overcurrent device (210.20(A)) and feeder conductors (215.2(A)(1)), while noncontinuous load is added at 100 percent.
NEC 2023 Section 210.20(A)Motor branch-circuit conductors — 430.22vsMotor feeder conductors — 430.24
A single motor's branch-circuit conductors must be at least 125 percent of that motor's full-load current, while feeder conductors must be at least 125 percent of the largest motor's FLC plus 100 percent of the FLC of all other motors.
NEC 2023 Section 430.22, Table 430.248Nontime delay fuse for AC polyphase motorvsInverse time circuit breaker for wound-rotor motor
Per Table 430.52, a nontime delay fuse is permitted at up to 300 percent of motor full-load current, while an inverse time breaker on a wound-rotor motor is limited to 150 percent of full-load current (next standard size permitted where the calculation does not correspond).
NEC Table 430.52, Table 430.250, 430.52(C)(1)Plug fuses rated 15 amperes and lowervsPlug fuses rated above 15 amperes
Per 240.50(C), 15-ampere and lower plug fuses must be identified by a hexagonal configuration of the window, cap, or other prominent part to distinguish them from higher-rated fuses.
NEC 2023 Section 240.50(C)Main/system bonding jumper screw identificationvsIncorrect red identification
Per 250.28(B), when the main or system bonding jumper is a screw only, the screw must be identified with a GREEN finish visible with the screw installed — not red.
NEC 2023 Section 250.28(B)Key Terms
Stranded conductor requirement in raceways (310.3(C)) NEC 2023 Section 310.3(C)
Where installed in raceways, conductors 8 AWG and larger must be stranded rather than solid, unless specifically permitted or required elsewhere in the Code to be solid.
Fixture wire (Article 402) NEC 2023 Section 402.3
Wire for luminaire wiring that shall not be smaller than 18 AWG (402.6) and, as listed in Table 402.3 (402.3 Types), is suitable for service at 600 volts nominal unless otherwise specified; Type FFH-2 is rated 75°C (167°F) and Type RFHH-2 is rated 90°C (194°F).
Prohibited uses of flexible cords (400.12) NEC 2023 Section 400.12
Flexible cords, flexible cables, cord sets, and power supply cords shall not be used as a substitute for the fixed wiring of a structure, nor run through holes in walls, structural ceilings, suspended ceilings, dropped ceilings, or floors.
Show window and showcase cords (400.15) NEC 2023 Section 400.15
Flexible cords in show windows and showcases must be Types S, SE, SEO, SEOO, SJ, SJE, SJEO, SJEOO, SJO, SJOO, SJT, SJTO, SJTOO, SO, SOO, ST, STO, STOO, or their 'W' variants; Types C and PD are not permitted.
Flexible cord surface marking (400.6(A)) NEC 2023 Section 400.6(A)
Certain flexible cords must be durably marked on the surface at intervals not exceeding 610 mm (24 in.) with the type designation, size, and number of conductors.
Portable power feeder cable (400.44, 400.47, Table 400.51(A)(3)) NEC 2023 Section 400.44(A)
Cable for feeders over 2000 volts that must use 6 AWG copper or larger flexible stranding, have a minimum bending radius of eight times the cable outer diameter for 5001–25,000 volts, and be derated by 0.65 when 2 layers are wound on a reel; single-conductor Type SH at 15,001–25,000 volts is permitted in sizes 1–500 AWG/kcmil.
Branch circuits derived from autotransformers (210.9) NEC 2023 Section 210.9
Branch circuits shall not be derived from autotransformers unless the circuit supplied has a grounded conductor electrically connected to a grounded conductor of the system supplying the autotransformer.
Optional calculation for a dwelling unit (220.82(A)) NEC 2023 Section 220.82(A)
Permitted where the total connected load is served by a single 120/240-volt or 208Y/120-volt set of 3-wire service or feeder conductors with an ampacity of 100 amperes or greater.
Receptacle outlet load (220.14(I)) NEC 2023 Section 220.14(I)
Each single or each multiple receptacle on one yoke (including a duplex receptacle) is calculated at not less than 180 volt-amperes.
Non-dwelling receptacle demand factors (Table 220.47) NEC 2023 Table 220.47
The first 10 kVA of calculated receptacle load is taken at 100 percent and the remainder over 10 kVA at 50 percent.
General lighting unit load for retail (Table 220.42(A)) NEC 2023 Table 220.42(A)
Retail occupancies use 1.9 volt-amperes per square foot, and per the table note the 125 percent continuous-load multiplier is already included so no additional multiplier is required.
Feeder tap not over 10 ft (240.21(B)(1)) NEC 2023 Section 240.21(B)(1)
Tap conductors that leave the enclosure or vault where the tap is made must have an ampacity not less than one-tenth of the rating of the feeder overcurrent device, and must also be not less than the combined calculated loads.
Supplemental grounding electrode bonding jumper (250.53(E)) NEC 2023 Section 250.53(E)
Where the supplemental electrode is a rod, pipe, or plate, the portion of the bonding jumper that is the sole connection to it is not required to be larger than 6 AWG copper or 4 AWG aluminum/copper-clad aluminum.
Free conductor length at boxes (300.14) NEC 2023 Section 300.14
At least 150 mm (6 in.) of free conductor, measured from where it emerges from the raceway or cable sheath, must be left at each outlet, junction, and switch point for splices or connection of luminaires or devices.
Switch/circuit breaker mounting height (404.8(A)) NEC 2023 Section 404.8(A)
Switches and circuit breakers must be installed so the center of the grip of the operating handle in its highest position is not more than 2.0 m (6 ft 7 in.) above the floor or working platform.
Support prohibition — vegetation (230.10 and 225.26) NEC 2023 Section 230.10
Vegetation such as trees shall not be used to support overhead service conductors or service equipment, nor overhead conductor spans for outside branch circuits and feeders — an absolute prohibition.
Transformer vault storage (450.48) NEC 2023 Section 450.48
Materials shall not be stored in transformer vaults, regardless of whether the materials are combustible or noncombustible.
Elevator feeder demand factors (Table 620.14) NEC 2023 Table 620.14
Demand factors applied to elevator feeders based on 50 percent duty cycle: 1 = 1.00, 2 = 0.95, 3 = 0.90, 4 = 0.85, 5 = 0.82, 6 = 0.79, 7 = 0.77, 8 = 0.75, 9 = 0.73, 10 or more = 0.72.
Crane/hoist power supply ampacity (610.14(E)(2)) NEC 2023 Section 610.14(E)(2)
For multiple motors on a single crane or hoist, minimum conductor ampacity is the nameplate full-load ampere rating of the largest motor or group of motors for any single crane motion plus 50 percent of the next largest.
Horsepower-to-watts constant Electrical conversion constants (1 hp = 746 W)
One horsepower equals 746 watts (550 ft-lb per second is the mechanical definition, not the electrical constant).
Formulas to Know
Ohm's Law and power (single-phase/DC)
P = E × I; I = P ÷ E; R = E ÷ I (or R = E² ÷ P). Example: 1200 W at 120 V → I = 1200/120 = 10 A, R = 120/10 = 12 Ω.Series and parallel circuit totals
Series: RT = R1 + R2 + R3 and IT = I1 = I2 = I3. Parallel: ET = E1 = E2 = E3 and IT = I1 + I2 + I3 (equal resistors in parallel: R ÷ number of branches). Example combination: RT = 2 Ω + (18 Ω ÷ 3) = 8 Ω, I = 24 V ÷ 8 Ω = 3 A.Three-phase power and current (1.73 = √3)
kW = (E × I × PF × 1.73) ÷ 1000; I = (kW × 1000) ÷ (E × PF × 1.73). Example: (460 × 52 × 0.80 × 1.73) ÷ 1000 ≈ 33 kW.Cost of operating a load
Cost = (Watts × Hours Used × Rate per kWh) ÷ 1000. Example: 5000 W × (12 hr × 30 days) × $0.15 ÷ 1000 = $270 per month.Continuous load sizing — branch OCPD and feeder ampacity
Branch-circuit OCPD ≥ 125% of continuous load (16 A × 1.25 = 20 A). Feeder/branch conductor ampacity ≥ noncontinuous load + 125% of continuous load (80 A + [60 × 1.25] = 155 A; 30 A + [100 × 1.25] = 155 A).Motor conductor sizing
Single motor branch circuit (430.22): ampacity ≥ 125% × FLC from Table 430.248/430.250 (28 A × 1.25 = 35 A). Feeder (430.24): ≥ (125% × largest motor FLC) + FLC of all other motors (65 × 1.25 + 40 = 121.25 A; 15.2 × 1.25 + 15.2 + 15.2 = 49.4 A).Motor branch-circuit short-circuit/ground-fault protection maximum
Nontime delay fuse: 300% × FLC (300% × 65 A = 195 A → next standard size 200 A permitted per 430.52(C)(1) Ex. 1). Inverse time breaker, wound-rotor motor: 150% × FLC (40 A × 1.50 = 60 A, a standard size per 240.6(A)).Generator conductor ampacity (445.13)
Conductor ampacity ≥ 115% of generator nameplate current rating: 80 A × 1.15 = 92 A minimum.Junction box sizing — angle pull (314.28(A)(2))
Distance to opposite wall ≥ (6 × trade size of largest raceway) + sum of diameters of all other raceway entries in the same row on the same wall: (6 × 3 in.) + 2 in. = 20 in.Parallel conductor sets — total ampacity and grounded conductor size
Total ampacity = ampacity of one set × number of sets (350 kcmil Cu at 90°C = 350 A; 2 sets = 700 A). For grounded conductor sizing, add parallel areas (2 × 350 = 700 kcmil) and use Table 250.102(C)(1): over 600 through 1100 kcmil → 2/0 AWG copper.