Electrical theory and exam arithmetic on the Texas journeyman exam

A small block that carries weight

Our bank holds thirty-nine questions in this area, and the published outline does not give theory a line of its own. What theory does is sit underneath the calculations portion, which is the half of the exam with a 20.56 percent pass rate in fiscal 2025. An error in the arithmetic habits here repeats through every load and conductor item you touch.

The Texas journeyman exam is two separately scored papers taken in one sitting. NEC Knowledge is 56 scored items inside 59 sat, with 130 minutes on the clock. Calculations is 24 scored inside 26 sat, with 110 minutes. Each half passes at 70 percent on its own, so you can clear one and rebook the other. For fiscal 2025 TDLR reports 24.46 percent passing the knowledge portion and 20.56 percent passing calculations, out of 26,303 attempts across every Texas electrical exam that produced 6,181 passes.

The second step behind the first

Ohms law and power calculations both cover it, and the defense is the same on both: read what the stem gives you and what it asks for before you reach for anything.

The six topics

• Ohm's law is five scored items on the Texas journeyman exam and the arithmetic inside a hundred more. Five scored items, and the ones that hide a second step behind the first.
• Series and parallel circuits come down to two sentences, and the Texas exam tests what follows from them. Which quantity is common, which one divides, and what the stem is really asking.
• Watts, volt-amperes and power factor, and which one a Texas exam item is actually asking for. Watts against volt-amperes, and the power factor the item leaves out.
• Rounding up to the next standard overcurrent device size, and the three conditions Texas exam items are built on. 240.4(B) permits it, 240.6 lists the sizes, and the exceptions are the item.
• Multiwire branch circuits, the simultaneous disconnect at 210.4(B), and the condition candidates invent. 210.4 handle ties, the shared neutral, and what an open neutral does.
• Interrupting rating, short-circuit current rating and available fault current, and which one an exam item means. 110.24 field marking, and the rating the equipment has to survive.

The habit worth the most marks

One hundred and seventy-six of the five hundred questions in our bank involve rounding to a standard size somewhere in the working. That makes rounding and the next standard size the page on this site with the widest reach, and it is the one nobody studies. 240.4(B) permits the round up under stated conditions, 240.6 lists the standard ratings, and the exceptions are what the item is usually testing.

Nineteen questions test the rounding rule directly. The other one hundred and fifty-seven just require you to get it right on the way to something else.

What this area skips

Two things you can safely leave alone. The bank holds one question that names a multiwire branch circuit directly, though the topic is worth an hour for what an open neutral does. And available fault current is thin: four questions carry it, all anchored on 110.24 field marking. Neither rewards more than an evening.

The unit that decides the item

A large share of theory misses come from a unit that was carried wrong. Volt-amperes and watts part company the moment power factor is anything other than one, and the item that hands you a power factor is testing whether you noticed it. The power page works both directions.

The other unit problem is the divisor. A volt-ampere total divided by 120 on a three wire system produces a current that is twice what the item wanted, and that number is on the paper. The stem always says which system it is, and reading that line is the whole defense.

Why this area is worth more than 39 questions

Theory questions are cheap to answer and expensive to skip, because the arithmetic habits here sit underneath the calculations portion. Rounding appears in one hundred and seventy-six of the five hundred. Series and parallel reasoning appears inside conductor and grounding items that are filed elsewhere. Power arithmetic sits inside every load calculation on the paper.

A candidate who is solid here reads a calculations item and sees the structure. A candidate who is shaky here reads the same item and starts hunting for a formula, which is the difference between four minutes and seven. Load calculations is where that difference gets paid.

What to do with this before test day

Drill the round up until it is automatic, because it sits inside a third of the bank. Then work timed theory sets and watch for the items where your first number was a choice on the paper. That pattern is the whole of this area. Thirty free questions, timed mixes theory with the rest, which is how it arrives on the day.

The worked theory arithmetic is in the question set.

Questions people ask

Is electrical theory a separate section on the Texas exam?

The content outline PSI publishes does not name theory as one of the ten subject areas on either portion. Theory sits underneath the calculations portion instead, inside items filed as branch circuit calculations, services, feeders and motors. That is why it is easy to skip and expensive to skip. The calculations portion had a 20.56 percent pass rate in fiscal 2025, and an arithmetic habit that is slightly wrong repeats across every item that relies on it.

Why do I get Ohms law questions wrong when I know the formula?

Because the item asks for something the formula you reached for does not produce in one step. The common shape gives you a current and a resistance and asks for power, where the working needs voltage first. The number you get from the single step is offered as an answer choice, which is why it feels right. Reading what the stem gives and what it asks for before touching a formula is a slower start and a faster finish.

How important is rounding up to the next standard size?

It is the habit that pays out across the widest part of this exam. One hundred and seventy-six of the five hundred questions in our bank involve rounding to a standard size somewhere in the working, and nineteen of those test the rule itself. 240.4(B) sets out when the round up is permitted, 240.6 lists the standard ratings, and the exceptions are usually the point of the item. Most candidates never study it directly, which means the error shows up scattered through their practice results and looks like bad luck.

What does an open neutral do on a multiwire branch circuit?

It puts the two line to neutral loads in series across the full line to line voltage, so the voltage divides between them according to their resistances. A lightly loaded appliance can see far more than its rated voltage and a heavily loaded one far less. That is the reason 210.4 requires the handle tie: opening one ungrounded conductor while leaving the other energized is what creates the condition in the first place, and the tie makes both open together.

How much is available fault current tested?

Lightly. Four questions in our bank carry it, and they anchor on 110.24, which requires the available fault current at service equipment to be field marked and the marking to be updated when the supply changes. The related idea that equipment has to have an interrupting rating adequate for the current available at its line terminals is worth understanding as a concept. Neither the marking rule nor the concept rewards more than an evening of study on a journeyman paper.