Exam Cheat Sheet · Quick Reference
Texas Residential Wireman Electrician
Texas · 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
80
Passing score
70%
Exam time
240 min
Administered by
PSI Services Contractor
Format
Reference materials allowed
Texas State Portion 80 questions
Definitions, Calculations, Theory, and Plans
8 Q · 10%
Branch-circuit, feeder, and service load calculations using demand factorsDwelling unit load calculations including lighting, small appliance, and laundry circuitsNEC code arrangement, mandatory vs. permissive rules, and enforcement authorityGrounding electrode system types, sizing, and installation requirementsOvercurrent protection sizing and location requirements for conductors and equipmentGFCI and AFCI protection requirements by location and occupancy typeDwelling unit receptacle and lighting outlet placement requirementsUnits of measurement, nominal voltages, and rounding conventions used in calculations
Electrical Services, Service Equipment, and Separately Derived Systems
16 Q · 20%
Service conductor clearances and installation requirements (overhead and underground)Service disconnecting means location, rating, and maximum numberService entrance conductor sizing, ampacity, and permitted wiring methodsService equipment overcurrent protection and ground-fault protection requirementsGrounding and bonding of service-supplied AC systems and service equipmentGrounding electrode system types, installation, and conductor sizingSeparately derived system grounding, bonding jumpers, and grounding electrode connectionsSurge-protective devices and emergency disconnects for dwelling services
Electrical Feeders
7 Q · 9%
Minimum feeder conductor ampacity for continuous and noncontinuous loads (125% rule and exceptions)Feeder overcurrent protection requirements and ratingsFeeder load calculations including demand factors for dwelling units, multifamily, and non-dwelling occupanciesFeeder conductor sizing using ampacity correction and adjustment factorsGround-fault protection of equipment for feeder disconnects rated 1000 amperes or moreSurge-protective device (SPD) requirements for feeders supplying dwelling and care facility unitsFeeder conductor and equipment grounding conductor identification and labelingOutside feeders: clearances, disconnecting means, number of supplies, and ratings for buildings supplied by feeders
Branch Circuit Calculations and Conductors
14 Q · 18%
Minimum conductor ampacity and sizing for continuous and noncontinuous loads (210.19, 215.2)Overcurrent protection ratings for branch circuits including continuous load calculations (210.20, 240.4)GFCI protection requirements by location for dwelling and non-dwelling occupancies (210.8)AFCI protection requirements and approved means of protection for dwelling units (210.12)Branch circuit ratings and permissible loads by circuit size (210.18, 210.23, 210.24)Dwelling unit load calculations including lighting, small-appliance, and cooking appliance loads (220.41, 220.52, 220.55)Conductor ampacity tables, temperature correction, and adjustment factors for more than three current-carrying conductors (310.15, 310.16)Required receptacle outlet placement in dwelling units including kitchens, bathrooms, garages, and outdoor locations (210.52)
Electrical Wiring Methods and Electrical Materials
10 Q · 12%
Conductor types, insulation ratings, and ampacity tables (Articles 310, 402)Physical protection of cables and raceways through framing members and structural elements (Article 300.4)Underground installation requirements and minimum cover depths (Article 300.5)Nonmetallic-sheathed cable (Type NM/NMC) uses, securing, and support intervals (Article 334)Outlet, device, junction, and pull box sizing, fill calculations, and support requirements (Article 314)Armored cable (Type AC) and metal-clad cable (Type MC) uses, bending radius, and securing requirements (Articles 320, 330)Flexible cord and fixture wire types, permitted uses, and ampacity (Articles 400, 402)Corrosion protection, raceway sealing, and wiring in environmental air spaces (Articles 300.6, 300.7, 300.22)
Electrical Equipment and Devices
12 Q · 15%
Switch types, ratings, and permitted uses (AC/DC snap switches, dimmers, knife switches, circuit breakers as switches)Receptacle ratings, grounding types, and termination requirements (CO/ALR, tamper-resistant, weather-resistant, isolated ground)Luminaire installation requirements by location (wet/damp, clothes closets, bathtub/shower areas, recessed)Panelboard and switchboard installation, overcurrent protection, and grounding requirementsMotor branch-circuit conductor sizing and overload protection requirementsDisconnecting means requirements for motors, appliances, air-conditioning equipment, and generatorsTransformer overcurrent protection, installation, and vault requirementsAppliance branch-circuit ratings, GFCI protection requirements, and flexible cord use
Motors and Generators
2 Q · 2%
Motor branch-circuit conductor sizing and ampacity requirements (125% rule, single and multiple motors)Motor overload protection selection, ratings, and placement (separate devices, thermal protectors, trip current percentages)Branch-circuit short-circuit and ground-fault protective device ratings for motors (Table 430.52, fuse and circuit breaker maximums)Motor disconnecting means requirements (type, location, rating, in-sight rule)Motor controller requirements (ratings, markings, horsepower ratings, number of motors served)Motor and controller nameplate marking requirements (locked-rotor code letters, design letters, service factor)Generator installation requirements (overcurrent protection, conductor ampacity, disconnecting means, emergency shutdown)Motor control center requirements (overcurrent protection, grounding, busbar arrangement, marking)
Electrical Control Devices and Disconnecting Means
2 Q · 2%
Switch connection requirements and grounded conductor rules (Article 404.2)Motor disconnecting means location, type, and rating requirements (Article 430, Part IX)Switch and circuit breaker ratings, types, and load control limitations (Article 404.14)Panelboard and switchboard overcurrent protection and installation requirements (Article 408)Motor controller ratings, design, and disconnecting means (Article 430, Parts VII and IX)Switch and enclosure accessibility, mounting height, and position requirements (Article 404.6–404.8)Industrial control panel supply conductor sizing, overcurrent protection, and disconnecting means (Article 409)Enclosure requirements for switches, circuit breakers, and motor controllers in damp/wet locations (Articles 404.4, 408.16, 408.37)
Special Occupancies, Equipment, and Conditions
7 Q · 9%
Classification of hazardous locations (Class I, II, III and Division 1 vs. Division 2)Material group classifications for Class I (Groups A, B, C, D) and Class II (Groups E, F, G)Protection techniques for classified locations (explosionproof, dust-ignitionproof, intrinsically safe, purged/pressurized, nonincendive, etc.)Wiring methods permitted in Class I, II, and III Division 1 and Division 2 locationsSealing and drainage requirements for conduit and cable systems in hazardous locationsEquipment marking requirements including temperature class (T codes), class, division, and groupSpecial occupancy requirements for commercial garages, aircraft hangars, motor fuel dispensing facilities, bulk storage plants, and spray application areasHealth care facility wiring requirements including patient care spaces, essential electrical systems, and isolated power systems
Renewable Energy Technologies
2 Q · 2%
PhotovoltaicsElectric Vehicle Chargers
Key Distinctions
NEC Chapters 1, 2, 3 and 4vsNEC Chapters 5, 6 and 7
Chapters 1–4 apply generally to all electrical installations, while Chapters 5, 6 and 7 cover special occupancies, special equipment or other special conditions and may supplement or modify the general requirements.
NEC 2026 Section 90.3Continuous loadvsNoncontinuous load
The 125 percent multiplier is applied only to the continuous load portion; the noncontinuous load is added at 100 percent when sizing branch-circuit/feeder conductors and overcurrent devices.
NEC 2026 Section 210.193 percent voltage dropvs5 percent voltage drop
The Informational Note to 210.19 recommends branch-circuit conductors be sized so voltage drop does not exceed 3 percent at the farthest outlet, while the combined feeder plus branch-circuit drop to the farthest outlet should not exceed 5 percent.
NEC 2026 Section 210.19, Informational NoteSmall-appliance branch circuits (dwelling)vsLaundry branch circuit (dwelling)
Dwelling units require two or more 20-ampere small-appliance branch circuits for the receptacle outlets of 210.52(B), but only at least one additional 20-ampere circuit for the laundry receptacle outlet(s) of 210.52(F).
NEC 2026 Section 210.11Type SO flexible cordvsType SJ flexible cord
Per Table 400.4, Type SO is rated 600 volts for extra-hard usage in damp locations, while Type SJ (junior hard service) is rated for pendant or portable use in damp locations at hard usage only.
NEC 2026 Table 400.4GEC to rod, pipe, or plate electrode onlyvsGEC to concrete-encased electrode only
Where it does not extend to other electrode types requiring a larger conductor, the GEC need not be larger than 6 AWG copper (4 AWG aluminum) for a rod/pipe/plate electrode, but need not be larger than 4 AWG copper for a concrete-encased electrode.
NEC 2026 Section 250.66Multiwire branch circuit supplying line-to-neutral loadsvsMultiwire branch circuit supplying line-to-line loads
Multiwire branch circuits shall supply only line-to-neutral loads, except they are permitted to supply line-to-line loads where they supply only one utilization equipment or where all ungrounded conductors are opened simultaneously by the branch-circuit overcurrent device.
NEC 2026 Section 210.4Ratings for other than individual branch circuitsvsRatings for individual branch circuits
Per 210.18, circuits other than individual branch circuits are rated 10, 15, 20, 30, 40 and 50 amperes (50 A being the maximum standard multioutlet rating), while individual branch circuits may have other ratings based on the load served and Exception No. 1 permits multioutlet circuits over 50 A for nonlighting outlet loads under specific conditions.
NEC 2026 Section 210.18Grounded conductor identification in a multiconductor cablevsWhite/gray conductor reidentified as an ungrounded conductor
Per 200.6(E) the grounded conductor in a multiconductor cable is identified by a continuous white or gray outer finish or three continuous white/gray stripes on other than green insulation, whereas per 200.7(C) a white or gray conductor used as ungrounded at 50 volts or more must be permanently reidentified by painting, taping or other effective means in a color other than white, gray or green at each visible and accessible location.
NEC 2026 Section 200.7(E)Hermetic motor-compressor conductor sizingvsHermetic motor-compressor overcurrent device sizing
Branch-circuit conductors must be at least 125 percent of the rated-load current (440.32), while the branch-circuit protective device must not exceed 175 percent of RLA (440.22(A)), with the next higher standard size permitted and a 225 percent ceiling only if needed for starting.
NEC 2026 Section 440.22(A), 440.32Generator output conductorsvsMotor feeder conductors
Conductors from generator terminals to the first overcurrent device must be rated at least 115 percent of the generator nameplate current, while a motor feeder is sized at 125 percent of the largest motor FLC plus 100 percent of the other motors' FLC.
Cables/raceways needing steel plate protection in notched woodvsWiring methods exempt from the steel plate
Where the required clearance cannot be maintained, cables and raceways must be protected by a steel plate at least 1.6 mm (1/16 in.) thick, but rigid metal conduit, intermediate metal conduit, rigid nonmetallic conduit and electrical metallic tubing do not require the plate.
NEC 2026 Section 300.6(A)(1)Key Terms
Multiwire branch circuit NEC 2026 Section 210.4
A branch circuit recognized by Article 210 that is permitted to be multiwire and that must supply only line-to-neutral loads except as specifically permitted.
Small-appliance branch circuit NEC 2026 Section 210.11
One of the two or more 20-ampere circuits required in dwelling units in addition to other required branch circuits to supply the receptacle outlets specified by 210.52(B).
Laundry branch circuit NEC 2026 Section 210.11
At least one additional 20-ampere branch circuit required in a dwelling unit to supply the laundry receptacle outlet(s) required by 210.52(F).
Continuity of the grounded conductor NEC 2026 Section 200.4(B)
Per 200.2(B), the continuity of a grounded conductor shall not depend on a connection to a metal enclosure, raceway, or cable armor.
Neutral conductor use restriction NEC 2026 Section 200.6(A)
Per 200.4(A), a neutral conductor shall not be used for more than one branch circuit, more than one multiwire branch circuit, or more than one set of ungrounded feeder conductors unless specifically permitted elsewhere in the Code.
AFCI protection (dwelling unit) NEC 2026 Section 210.12
Per 210.12(B), all 120-volt, single-phase, 10-, 15- and 20-ampere branch circuits supplying outlets or devices in listed locations such as bedrooms must be protected by one of the means in 210.12(A)(1) through (A)(6).
Free conductor at outlets NEC 2026 Section 300.16
Per 300.14, at least 150 mm (6 in.) of free conductor, measured from where it emerges from the raceway or cable sheath in the box, must be left at each outlet, junction and switch point for splices or connection of luminaires or devices.
Bored hole clearance in wood members NEC 2026 Section 300.6(A)(1)
Per 300.4(A)(1), holes for cables or raceways through joists, rafters or wood members must be bored so the edge of the hole is not less than 32 mm (1¼ in.) from the edge of the wood member.
40 percent conduit fill NEC 2026 Chapter 9, Table 1
Per Chapter 9, Table 1, with more than 2 conductors or cables the total conductor cross-sectional area shall not exceed 40 percent of the internal cross-sectional area of the conduit or tubing.
Chapter 3 wiring method voltage limit NEC 2026 Section 300.4(A)
Per 300.2(A), Chapter 3 wiring methods are used for 1000 volts AC, 1500 volts DC, nominal, or less, where not specifically limited elsewhere in Chapter 3.
Minimum cover for direct burial NEC 2026 Table 300.7(A) (NEC 2023: 300.5(A)); NEC 2026 Table 300.7(A)
Per Table 300.5(A), direct-buried cables or conductors in all locations not otherwise specified require a minimum cover of 600 mm (24 in.).
Raceway sealing for condensation NEC 2026 Section 300.9(A)(1)
Per 300.7(A), where portions of a raceway are subjected to different temperatures and condensation is known to be a problem, the raceway must be sealed to prevent circulation of warm air to a colder section.
Flexible cord overcurrent protection NEC 2026 Section 400.16
Per 400.16, flexible cords not smaller than 18 AWG (and tinsel cords or equivalent smaller cords approved for specific appliances) are considered protected against overcurrent in accordance with 240.5.
Portable power feeder cable over 2000 volts NEC 2026 Section 400.44
Per 400.44(A), its conductors must be 6 AWG copper or larger and must employ flexible stranding.
Supplemental electrode spacing / bonding jumper NEC 2026 Section 250.53
Per 250.53(A)(3) multiple rod, pipe or plate electrodes must be not less than 1.8 m (6 ft) apart, and per 250.53(E) the portion of the bonding jumper that is the sole connection to a rod, pipe or plate supplemental electrode need not be larger than 6 AWG copper (4 AWG aluminum or copper-clad aluminum).
Load-side grounded conductor restriction NEC 2026 Section 250.24
Per 250.24(B), a grounded conductor shall not be connected to normally non-current-carrying metal parts, to equipment grounding conductors, or be reconnected to ground on the load side of the service disconnecting means except as otherwise permitted in the article.
Large-scale PV electric supply station NEC 2026 Section 691.4
A PV installation covered by Article 691 that, per 691.4, shall not be installed on buildings.
Multiple sources of power plaque NEC 2026 Section 705.10
Per 705.10, permanent plaques, labels or directories at each service equipment location for premises with interconnected power production sources must be marked 'CAUTION: MULTIPLE SOURCES OF POWER.'
Manufactured wiring system luminaire tap NEC 2026 Section 604.100, Exception No. 1
Per 604.100(A), Exception No. 1, a luminaire tap no longer than 1.8 m (6 ft) intended for connection to a single luminaire may contain conductors smaller than 12 AWG but not smaller than 18 AWG.
Freestanding office furnishings supply cord NEC 2026 Section 605.9
Per 605.9(A), the flexible power supply cord must be extra-hard usage type with 12 AWG or larger conductors, include an insulated equipment grounding conductor, and not exceed 600 mm (2 ft) in length.
Formulas to Know
Minimum branch-circuit conductor ampacity with continuous loads
Ampacity ≥ noncontinuous load + (1.25 × continuous load); e.g., 10 A + (16 A × 1.25) = 30 AMinimum overcurrent device / feeder rating with continuous loads
Rating ≥ noncontinuous load + (1.25 × continuous load), then use the next standard size from 240.6(A); e.g., 12 A × 1.25 = 15 A; 40 A + (60 A × 1.25) = 115 A → 125 A; feeder ampacity (100 A × 1.25) + 30 A = 155 AMinimum motor feeder conductor ampacity
(1.25 × FLC of largest motor) + sum of FLC of remaining motors; e.g., (1.25 × 15.2) + 15.2 + 15.2 = 49.4 AHermetic motor-compressor conductors and OCPD
Conductors ≥ 1.25 × RLA (e.g., 30 A × 1.25 = 37.5 A); OCPD ≤ 1.75 × RLA (30 A × 1.75 = 52.5 A → next standard 60 A permitted; maximum 2.25 × RLA only if needed to carry starting current)Inverse time circuit breaker for a motor
Maximum setting = 250% of FLC (50 A × 2.5 = 125 A; next standard size 150 A if the motor will not start); for starting, may be increased but not over 400% of FLC for currents of 100 A or less (60 A × 4 = 240 A)Generator conductor ampacity
Conductors from generator terminals to first overcurrent device ≥ 1.15 × nameplate current; 80 A × 1.15 = 92 A minimumApparent power from real power and power factor
S (kVA) = P (kW) ÷ PF; 200 kW ÷ 0.8 = 250 kVA (three-phase: P = √3 × V × I × cos θ)Dwelling unit general load (Article 220)
Total VA = (area in sq ft × 3 VA/sq ft) + (1500 VA × number of small-appliance circuits) + (1500 VA × number of laundry circuits); e.g., 2000 × 3 + 2 × 1500 + 1500 = 10,500 VA; per-unit totals are multiplied by the number of units before demand factorsPV source circuit maximum current and DC disconnect rating
Maximum current = 1.25 × sum of short-circuit current ratings of parallel-connected PV modules; DC disconnect ≥ 1.25 × maximum current rounded up to the next standard size (30 A × 1.25 = 37.5 A → 40 A)Maximum rating of one cord-and-plug-connected utilization equipment not fastened in place
Rating ≤ 80% of the branch-circuit ampere rating; 15 A × 0.80 = 12 A