Electrical terms glossary for the Texas journeyman exam
The Texas journeyman exam is open book, but the book only helps once you know what you are looking for. A candidate who can tell an equipment grounding conductor from a grounding electrode conductor, or apparent power from true power, turns to the right article and the right table the first time. This glossary groups twenty electrical theory and wiring terms by what they help you decide, gives each a one-line meaning and links a full page with an original drawing, a worked example where one fits and the mix-ups that cost points.
Every explanation here is in our own words. We never quote NEC definitions or reproduce its tables; where it helps we name the article, and you read the wording in your own 2026 NEC.
Grounding and bonding
How fault current gets home, and what ties the system to earth.
| Term | In one line | Full page |
|---|---|---|
| Bonding vs grounding | Metal parts tied together to clear faults, versus a connection to earth | Bonding vs grounding |
| EGC vs GEC | The fault path with the circuit, versus the conductor to the electrode | EGC vs GEC |
| Main bonding jumper | The single bond between neutral and equipment ground at the service | Main bonding jumper |
| Neutral conductor | The conductor from the neutral point, carrying the unbalanced current | Neutral conductor |
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Start the free 10-question checkConductors and protection
How much current a wire can carry, and what protects it.
| Term | In one line | Full page |
|---|---|---|
| Ampacity | The current a conductor can carry continuously without overheating | Ampacity |
| Conductor insulation types | What the letters in THHN, THWN-2 and XHHW mean | Conductor insulation types |
| Continuous load | Three hours or more at maximum current, sized at 125% | Continuous load |
| Overcurrent protection | Fuses and breakers that open on overloads and faults | Overcurrent protection |
| GFCI vs AFCI | Shock protection for people, versus arc detection to prevent fires | GFCI vs AFCI |
| Voltage drop | The voltage the wire uses up before the load gets it | Voltage drop |
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Wiring methods
Where the conductors go.
| Term | In one line | Full page |
|---|---|---|
| Raceway | An enclosed channel built to hold wires, such as conduit and tubing | Raceway |
| Box fill | How many conductors, devices and fittings a box may hold by volume | Box fill |
Theory
The physics under every calculation.
| Term | In one line | Full page |
|---|---|---|
| Resistance | Opposition to current, set by material, length, area and temperature | Resistance |
| Series vs parallel circuits | One path and one current, versus one voltage and many paths | Series vs parallel circuits |
| Impedance | Resistance and reactance combined, the opposition to AC | Impedance |
| Power factor | True power divided by apparent power | Power factor |
| Apparent vs true power | Volt-amperes the wires carry, versus watts that do work | Apparent vs true power |
| Single-phase vs three-phase | One alternating voltage, versus three spaced a third of a cycle apart | Single-phase vs three-phase |
| Wye vs delta | Windings joined at a center point, versus joined in a loop | Wye vs delta |
| Transformer kVA | The apparent power a transformer can deliver, and the current it sets | Transformer kVA |
How these terms show up on the exam
The PSI bulletin splits the exam into an NEC Knowledge portion and a Calculations portion, each passed separately, across ten subject areas. Theory terms sit in definitions, theory and plans. Grounding, bonding and transformers sit in services, service equipment and separately derived systems. Ampacity, continuous loads, overcurrent protection and GFCI and AFCI requirements sit in branch circuits and conductors, the largest area. Raceways and box fill sit in wiring methods and materials. The exam outline gives the item counts for each.
Practice with the tools
- Ohm's law calculator: volts, amperes, ohms and watts, including three-phase power.
- Series and parallel resistance calculator: total resistance with every step shown.
- Voltage drop calculator: single-phase and three-phase drop and percent.
- Transformer calculator: kVA to amperes on each side and the turns ratio.
- Texas journeyman lookup drill: finding things in the 2026 NEC on a clock.
For the NEC side of the same topics, see conductor ampacity, box fill, conduit fill and grounding electrode conductor sizing.
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Take the free 10-question check. It needs no signup and explains every answer, so you see whether theory, grounding or wiring methods costs you the most points. When you want the full method worked topic by topic, the Bonding Jumper course comes second.
Not affiliated with or endorsed by TDLR, PSI or NFPA. NEC and National Electrical Code are registered trademarks of NFPA.
Sources
Show the list
- Candidate Information Bulletin, Texas electricians (updated 9/15/2026), PSI for the Texas Department of Licensing and Regulation.
- NFPA 70, National Electrical Code (2026 edition), NFPA. Free read-only access with an account.
Facts checked 26 October 2026 against the sources listed above. If something has changed, tell us and we will correct it within 2 business days.
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