Exam Cheat Sheet · Quick Reference
Texas Master Sign 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
100
Passing score
70%
Exam time
300 min
Administered by
PSI Services Contractor
Format
Reference materials allowed
Texas State Portion 100 questions
Definitions, Calculations, and Theory
6 Q · 6%
Branch-circuit, feeder, and service load calculations using Article 220 demand factors and tablesConductor ampacity tables and temperature correction/adjustment factors (Article 310)Overcurrent protection sizing, types, and location requirements (Article 240)Grounding and bonding system requirements, electrode types, and conductor sizing (Article 250)NEC code structure, mandatory vs. permissive rules, and authority having jurisdictionUnits of measurement, voltage ratings, and rounding of calculationsEquipment grounding conductor identification and sizingGeneral wiring method requirements including conductor installation and protection (Article 300)
Electrical Services, Service Equipment, and Separately Derived Systems
16 Q · 16%
Service conductor requirements: overhead and underground installation, clearances, and wiring methodsService disconnecting means: location, rating, number, and grouping requirementsService overcurrent protection: overload protection, ground-fault protection of equipment, and arc energy reductionGrounding and bonding of services and separately derived systems: system bonding jumpers, grounding electrode conductors, and grounding electrode systemSwitchboards, switchgear, and panelboards: installation, overcurrent protection, marking, and clearancesTransformer installation and overcurrent protection: dry-type, liquid-insulated, and transformer vaultsService load calculations: feeder and service sizing, demand factors, and continuous load requirementsSurge protection, emergency disconnects, and equipment connected on the supply side of service disconnect
Electrical Feeders
3 Q · 3%
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 for grounded and equipment grounding conductorsGround-fault protection of equipment for feeders rated 1000 amperes or moreSurge-protective device (SPD) requirements for feeders supplying dwelling and similar occupanciesFeeder conductor identification for grounded, ungrounded, and equipment grounding conductorsOutside feeder installation requirements including clearances, disconnecting means, and number of supplies to buildings
Branch Circuit Calculations and Conductors
15 Q · 15%
Minimum conductor ampacity for continuous and noncontinuous loads (125% rule)Branch circuit ratings and permissible loads by circuit size (10A through 50A+)Overcurrent protection sizing for branch circuits including standard ampere ratingsConductor ampacity tables and correction/adjustment factors for temperature and conduit fillGFCI protection requirements by location for dwelling and non-dwelling occupanciesAFCI protection requirements by occupancy type and means of protectionMultiwire branch circuit requirements including disconnecting means and line-to-neutral loadsDwelling unit load calculations including general lighting, small-appliance, laundry, and cooking appliance loads
Electrical Wiring Methods and Electrical Materials
8 Q · 8%
Conductor types, insulation ratings, and temperature limitations (Article 310)Ampacity tables and correction/adjustment factors for current-carrying conductorsProtection of cables and raceways against physical damage (boring, notching, framing members)Underground installation requirements including minimum cover depths and backfillSecuring and supporting requirements for raceways and cable assembliesBox and conduit body fill calculations and sizing requirementsUses permitted and not permitted for Type AC, MC, NM, NMC, SE, USE, and IMC wiring methodsWiring in environmental air-handling spaces, plenums, and ducts
Electrical Equipment and Devices
10 Q · 10%
Switch types, ratings, and load control requirements (Articles 404.14, 404.7, 404.8)Receptacle installation, grounding, and replacement requirements (Article 406)Switchboards, switchgear, and panelboard installation and overcurrent protection (Article 408)Luminaire installation locations, supports, grounding, and wiring requirements (Article 410)Motor branch-circuit conductors, overload protection, and disconnecting means (Article 430)Transformer overcurrent protection, installation types, and vault requirements (Article 450)Air-conditioning and refrigerating equipment branch-circuit and disconnecting means requirements (Article 440)Generator overcurrent protection, disconnecting means, and emergency shutdown requirements (Article 445)
Motors
2 Q · 2%
Motor branch-circuit conductor sizing and ampacity requirements (Article 430, Part II)Motor overload protection selection and settings (Article 430, Part III)Branch-circuit short-circuit and ground-fault protective device ratings and settings (Article 430, Part IV)Motor disconnecting means types, location, and ratings (Article 430, Part IX)Motor controller ratings, markings, and requirements (Article 430, Part VII)Motor nameplate markings and locked-rotor code letters (Article 430.7)Motor control centers installation, grounding, and overcurrent protection (Article 430, Part VIII)Adjustable-speed drive systems conductor sizing and overload protection (Article 430, Part X)
Electrical Control Devices and Disconnecting Means
4 Q · 4%
Types and ratings of disconnecting means for motors and motor circuits (Articles 430 Part IX, 440 Part II)Location requirements for motor disconnecting means — in-sight, lockable, accessibleService disconnecting means — location, rating, number of disconnects, and marking (Article 230 Part VI)Switch connections, grounded conductor switching rules, and three-way/four-way switch wiring (Article 404)Rating and use of switches — AC/DC snap switches, dimmers, CO/ALR, cord-and-plug-connected loads (404.14)Panelboard and switchboard overcurrent protection, circuit directories, and grounding requirements (Article 408)Motor controller requirements — ratings, horsepower, disconnecting means serving as controller (Article 430 Parts VII, IX)Overcurrent protection location, standard ratings, and arc energy reduction for fuses and circuit breakers (Article 240)
Electric Signs and Outline Lighting
36 Q · 36%
Branch circuit requirements for electric signs (ratings, amperage limits, dedicated circuits)Disconnecting means requirements (location, accessibility, lockable provisions, control switch rating)Grounding and bonding of sign equipment and metal partsListing, labeling, and marking requirements for signs and outline lighting systemsNeon secondary-circuit wiring (over and under 1000 volts, GTO cable, conduit methods, conductor spacing)Transformers, electronic power supplies, and Class 2 power sources (ratings, ground-fault protection, voltage limits)Enclosures and location requirements (wet locations, clearances from vehicles and combustibles, drain holes)Neon tubing, electrode connections, and support requirements
Key Distinctions
Conductor ampacity (Table 310.16)vsMaximum overcurrent protection (240.4(D))
12 AWG THWN copper has a table ampacity of 25 A at 30°C, while the commonly cited 20 A figure is only the maximum overcurrent protection permitted for 12 AWG, not its ampacity.
NEC 2026 Table 310.16Class II, Division 1 locationvsClass III, Division 1 location
Class II Div 1 has combustible dust in the air under normal operating conditions in quantities sufficient to produce explosive/ignitible mixtures, while Class III Div 1 involves easily ignitible fibers/flyings that are not normally suspended in air but can collect on machinery or lighting.
NEC 2026 Section 500.5Class I locationvsClass II / Class III locations
Class I locations involve flammable gases or vapors (equipment surfaces must stay below the gas/vapor autoignition temperature), whereas Class II involves combustible dusts and Class III involves ignitible fibers/flyings.
NEC 2026 Section 500.5Neon tubing branch circuit (600.5(C)(1))vsAll other sign/outline lighting branch circuits (600.5(C)(2))
Branch circuits supplying neon tubing installations shall not be rated over 30 amperes, while branch circuits for all other signs and outline lighting are limited to 20 amperes.
NEC 2026 Section 600.5Emergency power source general minimum duration (700.12(C))vsStorage batteries/UPS for emergency illumination (700.12(C)(4))
The general emergency power source must supply the total load for at least 2 hours, while storage batteries and UPS used for emergency illumination need only 1½ hours, with load voltage not falling below 87½ percent of nominal.
NEC 2026 Section 700.12Branch-circuit conductor sizing (210.19(A)(1))vsFeeder/service conductor sizing (215.2(A)(1)(a), 230.42(A))
Branch-circuit conductors must be at least 125% of the continuous load, while feeder and service conductors must be at least 100% of the noncontinuous load plus 125% of the continuous load.
NEC 2026 Section 210.19Direct-burial cover for residential 120 V GFCI-protected branch circuit (12 in.)vsDirect-burial cover under driveways (18 in. residential / 24 in. general)
Residential branch circuits 120 V or less with GFCI protection and 20 A maximum overcurrent protection need only 300 mm (12 in.) cover, one- and two-family dwelling driveways need 450 mm (18 in.), and the general street/driveway/parking-lot category requires 600 mm (24 in.).
NEC 2026 Table 300.7(A)Wiring methods exempt from steel plate protectionvsWiring methods requiring steel plates
Rigid metal conduit, intermediate metal conduit, rigid nonmetallic conduit, and electrical metallic tubing are exempt from steel plate protection at notches and within 1¼ in. of framing edges, while nonmetallic-sheathed cable, Type MC cable, and flexible metal conduit require the plates.
NEC 2026 Section 300.6(A)(2)Type SO flexible cordvsType SOW flexible cord
Type SO is a hard-usage, oil-resistant thermoset cord listed for damp locations, while the 'W' suffix on Type SOW indicates a 600-volt cord suitable for extra-hard usage in damp and wet locations.
NEC 2026 Table 400.4Hard-service cords (Types S, SO)vsJunior hard-service (Type SJ) and light-duty cords (SPT-1, SPT-2, SV)
Hard-service cords carry hard/extra-hard usage ratings, while junior hard-service cords are damp-location only with smaller conductors and light-duty cords (SPT-1, SPT-2, SV) are rated not-hard usage; the 400.13 repair exception permits splicing of BOTH hard-service and junior hard-service cords 14 AWG and larger.
NEC 2026 Section 400.13Elevator raceway conductor fill (620.33)vsGeneral Chapter 9, Table 1 fill
Article 620.33 is a special elevator provision limiting the sum of conductor cross-sectional areas to 50 percent of the raceway interior area, differing from the standard Chapter 9, Table 1 fill percentages used in general wiring.
NEC 2023 Section 620.33Flexible cord equipment grounding conductor (400.23)vsEquipment grounding conductor per Table 250.122
250.122(F) permits cord EGCs to be sized per 400.23/Table 400.4 (as small as 18 AWG copper for certain cord types), whereas Table 250.122 otherwise requires a 14 AWG minimum.
NEC 2026 Section 400.23Straight pull box sizing (314.28(A)(1))vsAngle pull box sizing (314.28(A)(2))
Straight pulls require a box length of 8 times the largest conduit trade diameter, while angle pulls require 6 times the largest conduit trade diameter on that wall plus the sum of the trade diameters of the other conduits on the same wall.
NEC 2026 Section 314.28Key Terms
Class III, Division 1 location NEC 2026 Section 500.5
An area where easily ignitible fibers or materials producing combustible flyings are handled, manufactured, or used, though not normally suspended in air in ignitible quantities.
Autoignition temperature limit (Class I equipment) NEC 2026 Section 500.8
Class I equipment shall not have any exposed surface operating at a temperature in excess of the autoignition temperature of the specific gas or vapor present.
Sign transformer/electronic power supply secondary limits NEC 2026 Section 600.23
Secondary-circuit voltage shall not exceed 15,000 volts nominal under any load condition with no output terminal exceeding 7500 volts to ground, and the secondary-circuit current rating shall not exceed 300 mA.
Sign working space (600.21(D)) NEC 2026 Section 600.21
A working space at least 900 mm (3 ft) high × 900 mm (3 ft) wide × 900 mm (3 ft) deep must be provided at each ballast, transformer, electronic power supply, and Class 2 power source, or its enclosure, where not installed in a sign.
Neon secondary raceway minimum size (600.32(A)(3)) NEC 2026 Section 600.32
Conduit or tubing used for neon secondary circuits over 1000 volts nominal must be at least metric designator 16 (trade size 1/2).
Neon tubing spacing (600.41(C)) NEC 2026 Section 600.41
A spacing of not less than 6 mm (1/4 in.) must be maintained between neon tubing and the nearest surface other than its support.
Sign ballast thermal protection (600.22(B)) NEC 2026 Section 600.22
Ballasts used in electric signs shall be thermally protected — a mandatory requirement.
PV powered sign battery compartment (600.34(F)) NEC 2026 Section 600.34
Battery compartments in PV powered signs shall require a tool to open, preventing unauthorized access.
Multiwire branch circuit disconnect (210.4(B)) NEC 2026 Section 210.4
Each multiwire branch circuit must be provided with a means to simultaneously disconnect all ungrounded conductors at the point where the branch circuit originates.
Continuity of the grounded conductor (200.2(B), 300.13(B)) NEC 2026 Section 200.4(B)
Grounded conductor continuity shall not depend on a connection to a metal enclosure, raceway, or cable armor, nor on device connections such as lampholders or receptacles whose removal would interrupt continuity.
Grounded conductor identification NEC 2026 Section 200.7(B)(4)
Conductors 4 AWG or larger may be identified by a distinctive white or gray marking at terminations that encircles the conductor, while grounded conductors in multiconductor cable require a continuous white or gray outer finish or three continuous white/gray stripes on other than green insulation.
Equipment grounding conductor identification (250.119, 400.23) NEC 2026 Section 400.23
Equipment grounding conductors are identified by a continuous green color or continuous green with one or more yellow stripes, and such conductors may not be used for any other purpose.
Main/system bonding jumper screw (250.28(B)) NEC 2026 Section 250.28
Where the bonding jumper is a screw only, the screw must be identified with a green finish that is visible with the screw installed.
Warning ribbon (300.5(D)(3)) NEC 2026 Section 300.7(D)(3)
Underground installations not encased in concrete and buried 450 mm (18 in.) or more below grade must be identified by a warning ribbon in the trench at least 300 mm (12 in.) above the installation.
AFCI extension exception (210.12(E)) NEC 2026 Section 210.12
AFCI protection is not required where an extension of existing branch-circuit conductors is not more than 1.8 m (6 ft) and adds no outlets or devices other than splicing devices.
Service disconnecting means (230.71(B)) NEC 2026 Section 230.71(B)
Each service is limited to one disconnecting means unless 230.71(B) applies, which permits two to six service disconnects, with one-family dwelling service equipment rated not less than 100 amperes, 3-wire.
Connected load (210.11(B)) NEC 2026 Section 210.11
Branch-circuit overcurrent devices and circuits are only required to be installed to serve the connected load, even if the wiring system capacity is designed larger.
Flexible cord prohibition (400.12) NEC 2026 Section 400.12(1)
Flexible cords and cables shall not be used as a substitute for the fixed wiring of a structure and must be used in continuous lengths without splice or tap except for permitted repairs.
Formulas to Know
Branch-circuit conductor ampacity for continuous loads
Minimum ampacity = continuous load × 125% (e.g., 48 A × 1.25 = 60 A; 36 A × 1.25 = 45 A)Feeder/service conductor minimum ampacity
Minimum ampacity = (continuous load × 1.25) + (noncontinuous load × 1.00); e.g., (48×1.25)+30 = 90 A; (80×1.25)+30 = 130 A; (85×1.25)+45 = 151 AMaximum continuous load permitted on a circuit
Max continuous load = OCPD rating ÷ 1.25 (20 A ÷ 1.25 = 16 A)Number of branch circuits for a continuous lighting load
Circuits = (VA × 1.25) ÷ (circuit volts × circuit amps), rounded UP; e.g., (36,000 × 1.25) ÷ (120 × 20) = 45,000 ÷ 2,400 = 18.75 → 19 circuitsSingle-phase current and next standard OCPD
I = (kVA × 1000) ÷ line-to-line volts (45,000 ÷ 240 = 187.5 A); for service OCPD, I = VA ÷ V (28,800 ÷ 240 = 120 A) then select next standard size per 240.6(A) = 125 AThree-phase current from VA
I = VA ÷ (E × 1.732); e.g., 23,000 ÷ (208 × 1.732) = 63.9 ASingle-phase voltage drop
VD = (2 × K × I × D) ÷ CM with K = 12.9 for copper; e.g., (2 × 12.9 × 120 × 175) ÷ 105,600 = 5.1 V; recommended feeder limit is 3% (a recommendation, not a requirement)Adjusted (corrected) conductor ampacity
Adjusted ampacity = base ampacity from Table 310.16 (insulation temp column) × ambient temperature correction factor × conductor-count adjustment factor; e.g., 115 A × 1.00 × 0.80 = 92 A; 30 A × 0.91 × 0.70 = 19.1 A; 75 A × 0.91 × 0.80 = 54.6 A; 230 A × 0.82 = 188.6 AMotor branch-circuit and feeder conductor ampacity
Branch circuit: 125% × motor FLC from Table 430.248/430.250 (50 A × 1.25 = 62.5 A; 21 A × 1.25 = 26.25 A → 10 AWG; 74.8 A × 1.25 = 93.5 A → 3 AWG). Feeder: (125% × largest motor FLC) + 100% of all other motor FLCs, plus other loads per 215.2(A)(1) (e.g., 34×1.25 + 21 = 63.5 A; 143×1.25 + 60×1.25 = 253.75 A)Raceway fill and pull box minimum dimensions
Conduit fill: max conductors = 40% fill area (Ch. 9 Table 4) ÷ conductor area (Ch. 9 Table 5), rounded down unless the decimal is 0.8 or more (0.213 ÷ 0.0211 = 10.09 → 10); total fill must be ≤ the raceway 40% area. Pull boxes: straight pull = 8 × largest conduit trade size (8 × 3 in. = 24 in.); angle pull = (6 × largest conduit on that wall) + sum of other conduit trade sizes on the same wall (18 + 3.5 = 21.5 in.)