Texas Electrician ExamTexas journeyman & master

Checked against primary sources 2026-08-24

The neutral question is settled by the circuit, not by a measurement

Candidates answer this by asking how much the neutral is carrying. 310.15(E) never asks that, and the habit costs a point on almost every conductor count item.

On this page
  1. The wrong question, and the right one
  2. The one that stays out of the count
  3. The ones that are counted, and why each is counted differently
  4. What is never counted, and for a different reason
  5. The check, in order
  6. What the answer actually changes
  7. What this page cites

The wrong question, and the right one

Ask what kind of circuit it is and what kind of load is on it. The rule is written entirely in those terms and it never mentions a measured value (NEC 310.15(E)).

A neutral carrying 30 amperes can sit outside the count. A neutral carrying almost nothing can sit inside it. Meter readings settle none of this, which is exactly why the rule works at the design stage, before anything has been energized and before anyone could take a reading.

The section is built as a two-way switch. 310.15(E)(1) is a short positive list of the circuits in which the neutral is current-carrying. 310.15(E)(2) picks up everything the list did not take. Find which side of that switch the stem has put you on and the answer follows.

The confusion starts with the word balanced. Balance is a property of the loads at a moment. What the section cares about is whether the neutral is structurally carrying current that the ungrounded conductors are not already accounting for, and that is a property of the circuit.

The one that stays out of the count

Ambient temperature and conductor bundling are two separate corrections and they multiply Start from the ampacity in the table for the insulation rating. Multiply by the ambient temperature correction factor if the ambient is not thirty degrees Celsius. Multiply again by the adjustment factor if more than three current carrying conductors are bundled together. Then compare the result to the terminal rating. People commonly apply one of the two corrections and stop. tableampacity × ambientcorrection × bundlingadjustment = correctedampacity from the column for the insulation rating only if the ambient is not 30°C only if more than three are bundled now check this against the terminal rating both corrections apply if both conditions are true they are not either-or, and the exam writes questions where both bite
Two knobs, applied one after the other. Skipping the second one is a very common miss. Drawn against NEC 310.15(B) and 310.15(C)(1). Factors are in the tables in your book.

Unless the circuit is one of the three named in 310.15(E)(1), a neutral carrying only the unbalanced current from the other conductors of the same circuit shall not be considered current-carrying (NEC 310.15(E)(2)).

Read the qualifier before the rule. The exclusion only reaches circuits the positive list did not already take, so it can never be used to argue a neutral back out of the count on a two-wire circuit or on three wires off a wye. Candidates who learned this rule from an older book tend to have the exclusion first in their heads and the list second, and that ordering is what produces the wrong answer.

Within the circuits it does reach, read the words only and unbalanced as one condition rather than as two. A neutral in that position is carrying current that one of the ungrounded conductors is therefore not carrying. The total heat in the raceway has not gone up, the assumption behind the ampacity table still holds, and there is nothing to count.

That is the physics under the whole section, and it is worth holding because it lets you rebuild every other case from scratch. The adjustment factor exists because conductors bundled together cannot get rid of their heat. A conductor that adds no heat adds nothing to the count.

The everyday example is a three-phase, four-wire wye feeder supplying linear line-to-neutral loads. Three ungrounded conductors and a neutral in the raceway, three current-carrying conductors, no adjustment. That is the most common item on this subject in any bank, and the answer is three.

The ones that are counted, and why each is counted differently

All three sit in 310.15(E)(1), and the code states them as circuits rather than as conditions. That is why a well-built stem always names the system, and why a stem that names the system is telling you the answer if you are listening for it.

A two-wire circuit

One ungrounded conductor and one neutral. The neutral carries exactly what the ungrounded conductor carries, every moment it is energized. Nothing about it is unbalanced, because there is nothing for it to be unbalanced against. Two conductors, both counted, and this case is only ever missed by people applying the exclusion as a slogan.

Three wires taken off a four-wire wye

Two ungrounded conductors and the neutral, where the two phases sit 120 degrees apart rather than opposite each other. Add two equal currents 120 degrees apart and the result is not zero. It comes out equal in size to either one of them.

So the neutral of that circuit carries full load current when the two phases are perfectly matched. Balanced does not mean quiet here. This is the case that catches the most people, because in the raceway it looks identical to the single-phase three-wire circuit where balance really does empty the neutral out.

Hold the two pictures next to each other. Two legs 180 degrees apart and the neutral carries the difference. Two phases 120 degrees apart and the neutral carries about as much as either one. Same three wires, same pipe, opposite answers, and the only thing separating them is the clause in the stem that names the system.

A four-wire wye with a major portion of nonlinear load

All four counted, and this one is about harmonics rather than about geometry.

A nonlinear load draws current in pulses instead of following the voltage waveform. Those pulses carry a third harmonic component, and third harmonic currents from the three phases arrive at the neutral in step with one another instead of canceling. They add up. The neutral of a heavily nonlinear circuit can end up carrying more current than any single phase conductor feeding it.

Note which system the code names here, because it is the whole reach of the rule. 310.15(E)(1) attaches the nonlinear trigger to a four-wire, three-phase wye circuit. A single-phase three-wire circuit feeding a floor of switching power supplies is not swept in by it, and the physics agrees: two legs 180 degrees apart put their third harmonics 180 degrees apart as well, so those harmonics subtract in the neutral instead of stacking.

Major portion is the code's own phrase and it is a judgment rather than a percentage. On an exam the stem will say it outright, because the item writer knows nobody can infer it from a list of equipment.

What makes a load nonlinear is a switching supply in front of it. Electronic ballasts, LED drivers, computer power supplies and variable frequency drives all qualify. An office floor is nonlinear and a data room is emphatically nonlinear. A resistance heater is not, and neither is an incandescent lamp.

What is never counted, and for a different reason

A grounding or bonding conductor shall not be counted when the adjustment factors are applied (NEC 310.15(F)). It carries current during a fault, and a fault is not the sustained thermal condition the ampacity tables were built around.

Keep that reason separate from the neutral exclusion, because they are not the same argument and questions test the difference. A qualifying neutral is left out because its current is already accounted for somewhere else in the same circuit. A grounding conductor is left out because in normal service there is no current to account for at all.

Two more counting rules sit in the note printed under Table 310.15(C)(1) rather than in 310.15(E). Conductors connected to components that cannot be energized at the same time drop out of the count. Spare conductors stay in it, because a spare is one termination away from being a live circuit and the raceway will not know the difference.

The check, in order

  1. Name the system. Two-wire, single-phase three-wire, three-phase four-wire wye, or three wires taken off one of those.
  2. Check the system against the list in 310.15(E)(1). A two-wire circuit and three wires off a four-wire wye are both on it, so their neutrals go into the count on the system alone.
  3. If the system is a four-wire, three-phase wye, ask whether the stem says the major portion of the load is nonlinear. If it does, the neutral goes in. If the system is anything else, the load type does not move the answer.
  4. Anything the list did not take falls to 310.15(E)(2), so its neutral stays out.
  5. Count the ungrounded conductors, add the neutral if step two or step three put it in, add the spares, and leave the grounding conductors out.
  6. Only now open the adjustment table and read the band.

Steps two and three are the exercise. The rest is bookkeeping, and a bookkeeping slip is recoverable in a way that a misread system is not, because a misread system produces a clean number that no later step will contradict.

What the answer actually changes

The count picks the adjustment band, and the bands step down in blocks rather than smoothly. Get the neutral wrong on a circuit sitting near a band boundary and the conductor size changes. Get it wrong in the middle of a band and nothing changes at all, which is precisely why the error survives on real jobs and then surfaces under a clock.

It also changes how long the item takes you. Work the count last, after the lookups, and a wrong count means doing the lookups again. Work it first and it costs fifteen seconds and never has to be repeated. The journeyman knowledge portion gives you a little over two minutes an item on total items, so that is not a small piece of exam technique.

Keep this count apart from conduit fill, which counts every conductor in the raceway including the ones excluded here. Two counts, two purposes, one drawing. A well-built item hands you a single raceway and asks for both, and the candidate who has one number in their head answers half of it correctly.

What this page cites

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