Exam Cheat Sheet · Quick Reference

Texas - Journeyman Industrial 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
60
Passing score
70
Exam time
180 min
Administered by
PSI Services Contractor
Format
Reference materials allowed

Texas State Portion 60 questions

Definitions, Theory, and Plans 7 Q · 12%
Electrical Services, Service Equipment, and Separately Derived Systems 4 Q · 7%
Electrical Feeders 4 Q · 7%
Branch Circuit Calculations and Conductors 6 Q · 10%
Electrical Wiring Methods and Electrical Materials 10 Q · 17%
Electrical Equipment and Devices 6 Q · 10%
Motors and Generators 7 Q · 12%
Electrical Control Devices and Disconnecting Means 3 Q · 5%
Special Occupancies, Equipment, and Conditions 6 Q · 10%
Electrical Safety 7 Q · 12%

Key Distinctions

Mandatory NEC RulevsPermissive NEC Rule

Mandatory rules use 'shall' or 'shall not' (required/prohibited), while permissive rules use 'shall be permitted' or 'shall not be required' (optional/alternative).

NEC 90.5(A)
NEC Chapters 1–4vsNEC Chapters 5–7

Chapters 1–4 apply generally to all electrical installations, while Chapters 5–7 apply only to special occupancies, special equipment, or other special conditions and may supplement or modify Chapters 1–4.

NEC 90.3
NEC Chapter 8vsNEC Chapters 1–7

Chapter 8 (communications systems) is NOT subject to the requirements of Chapters 1–7 unless specifically referenced within Chapter 8.

NEC 90.3
Grounded ConductorvsEquipment Grounding Conductor (EGC)

Grounded conductors are identified by white, gray, or three white/gray stripes; EGCs are identified by a continuous green finish—green is never permitted for grounded conductors.

NEC 200.6(A)
Class II Hazardous LocationvsClass III Hazardous Location

Class II locations are hazardous due to combustible dusts, while Class III locations are hazardous due to easily ignitible fibers or flyings that are not normally suspended in air in ignitable concentrations.

NEC 500.5(D)(1)
1 Conductor in Conduit (53% fill)vs2 Conductors in Conduit (31% fill)

A single conductor may fill up to 53% of conduit cross-sectional area, whereas exactly two conductors are limited to 31% fill per NEC Table 1.

Table 1
2 Conductors in Conduit (31% fill)vsMore Than 2 Conductors in Conduit (40% fill)

Exactly two conductors are limited to 31% conduit fill, while any installation of more than two conductors is limited to 40% fill per NEC Table 1.

Table 1, Chapter 9
Informational NotesvsMandatory/Permissive Rules

Informational Notes are included for explanatory purposes only and are not enforceable, whereas mandatory and permissive rules carry the force of the Code.

Article 90.5(C)
NEC Coverage: Ships/WatercraftvsNEC Coverage: Mobile Homes/Recreational Vehicles

Ships and watercraft (other than floating buildings) are explicitly excluded from NEC coverage, while mobile homes and recreational vehicles are explicitly included.

NEC 90.2(D)
Multiwire Branch CircuitvsStandard Branch Circuit

A multiwire branch circuit must provide a means to simultaneously disconnect ALL ungrounded conductors at the point of origin; a standard single branch circuit has no such simultaneous-disconnect requirement.

NEC 210.4(B)
SI (Metric) UnitsvsInch-Pound Units

The NEC gives preference to SI (metric) units, which appear first; inch-pound units immediately follow in parentheses.

NEC 90.9(A), 90.9(B)
Autotransformer-Derived Branch CircuitvsConventional Branch Circuit

A branch circuit derived from an autotransformer is only permitted if its grounded conductor is electrically connected to the grounded conductor of the supply system; conventional branch circuits have no such restriction.

NEC 210.9

Key Terms

Purpose of the NEC (NEC 90.1(A) / 90.2(A)) NEC 90.2(A)
Per NEC 90.2(A), the Code's purpose is the practical safeguarding of persons and property from hazards arising from the use of electricity—not to serve as a design specification or instruction manual.
Authority Having Jurisdiction (AHJ) (NEC 90.4) NEC 90.4(B)
Per NEC 90.4(B), the AHJ is responsible for making interpretations of NEC rules, approving equipment and materials, and granting special permissions contemplated by the Code.
NEC Code Arrangement (NEC 90.3) Article 90.3
Per NEC 90.3, the Code consists of nine chapters: Chapters 1–4 apply generally, Chapters 5–7 cover special conditions, Chapter 8 covers communications systems (independent of Chapters 1–7), and Chapter 9 consists of applicable tables.
Mandatory Rule (NEC 90.5(A)) NEC 90.5(A)
Per NEC 90.5(A), a mandatory rule is one that requires or prohibits a specific action and is identified by the terms 'shall' or 'shall not.'
Permissive Rule (NEC 90.5(B)) NEC 90.5(B)
Per NEC 90.5(B), a permissive rule identifies an allowed but not required action and is characterized by the terms 'shall be permitted' or 'shall not be required.'
Informational Note (NEC 90.5(C)) Article 90.5(C)
Per NEC 90.5(C), Informational Notes are explanatory material included in the Code for informational purposes only and are not enforceable as Code requirements.
Conduit Fill – More Than 2 Conductors (NEC Table 1, Chapter 9) Table 1, Chapter 9
Per NEC Table 1, when more than 2 conductors are installed in a conduit or tubing, the maximum allowable fill is 40% of the conduit's cross-sectional area.
Class III, Division 1 Location (NEC 500.5(D)(1)) NEC 500.5(D)(1)
Per NEC 500.5(D)(1), a Class III, Division 1 location is one where easily ignitible fibers or materials producing combustible flyings are handled, manufactured, or used.
Grounded Conductor Identification – 6 AWG or Smaller (NEC 200.6(A)) NEC 200.6(A)
Per NEC 200.6(A), grounded conductors 6 AWG or smaller must have a continuous white finish, continuous gray finish, or three continuous white/gray stripes; green is not permitted.
Multiwire Branch Circuit Disconnection (NEC 210.4(B)) NEC 210.4(B)
Per NEC 210.4(B), each multiwire branch circuit must be provided with a means that simultaneously disconnects all ungrounded conductors at the point where the branch circuit originates.
EGC in Flexible Cord – 15A Circuit (NEC 250.122(E)) NEC 250.122(E)
Per NEC 250.122(E), the equipment grounding conductor in a flexible cord shall not be smaller than 18 AWG and shall not be smaller than the circuit conductors—making 14 AWG the minimum for a 15-ampere circuit.
Grounded Conductor Continuity (NEC 200.2(B)) NEC 200.2(B)
Per NEC 200.2(B), the continuity of a grounded conductor shall not depend on a connection to a metal enclosure, raceway, or cable armor.
Common, Continuous Grounded System (NEC 200.3) NEC 200.3
Per NEC 200.3, grounded conductors of premises wiring systems must be electrically connected to the supply system grounded conductor to ensure a common, continuous grounded system.
Grounded Conductor Terminal Color (NEC 200.10(B)) NEC 200.10(B)
Per NEC 200.10(B), the terminal on receptacles, attachment plugs, and cord connectors intended for the grounded conductor must be white or silver in color.
Autotransformer Branch Circuit Restriction (NEC 210.9) NEC 210.9
Per NEC 210.9, branch circuits shall not be derived from autotransformers unless the supplied circuit's grounded conductor is electrically connected to the grounded conductor of the system supplying the autotransformer.
Household Range Branch Circuit Minimum (NEC 210.19(C)) NEC 210.19(C)
Per NEC 210.19(C), branch-circuit conductors supplying household ranges rated 8¾ kW or more must have a minimum ampacity of 40 amperes.

Formulas to Know

Conduit Fill % (single conductor)Max fill = 53% of conduit cross-sectional area (1 conductor)
Conduit Fill % (2 conductors)Max fill = 31% of conduit cross-sectional area (exactly 2 conductors)
Conduit Fill % (>2 conductors)Max fill = 40% of conduit cross-sectional area (more than 2 conductors)
Conductor Cross-Sectional Area UsedFill area used = π × (conductor OD / 2)² [sum for all conductors, compare to allowed %]
Allowable Fill AreaAllowable area = (Fill % / 100) × π × (raceway ID / 2)²
Power (single-phase)P (watts) = V (volts) × I (amperes) × PF
Power (three-phase)P (watts) = √3 × V_L (line volts) × I_L (line amperes) × PF
Ohm's LawV = I × R → I = V / R → R = V / I
Voltage Drop (single-phase, copper)VD = (2 × K × I × L) / CM [K = 12.9 for copper, L = one-way length in ft, CM = circular mils]
Minimum EGC Size Check (flexible cord)EGC ≥ 18 AWG AND EGC ≥ circuit conductor size (per NEC 250.122(E))
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