How to Pass the Texas Electrician Calculations Exam

The calculations portion is where Texas electrician candidates fail most. In FY2025, 20.56% passed Journeyman Calculations and 19.08% passed Master Calculations, per TDLR. The math itself is not advanced. What sinks people is time, picking the wrong method, and small code traps. This guide covers all three.

Key facts

• Journeyman Calculations: 26 items (24 scored) in 110 minutes. Master Calculations: 33 items (30 scored) in 170 minutes.
• Residential Wireman has no separate calculations portion; calculations are mixed into its 80 scored items.
• You need 70%: about 17 of 24 for journeyman, about 21 of 30 for master.
• PSI instructions: no code exceptions or optional methods unless the question asks, and conductors are copper unless stated.
• The exam is open book, and PSI gives you an electronic notepad for working.

Your time budget

Exam	Items	Minutes	Per item (all items)	Per scored item
Journeyman Calculations	26	110	about 4.2	about 4.6
Master Calculations	33	170	about 5.2	about 5.7
Residential Wireman (whole exam)	85	about 260	about 3.1	3.0

TDLR’s July 2025 newsletter put it at about 4 minutes per calculation question for journeyman. You cannot tell which items are unscored, so budget on the “all items” column.

A practical plan for the journeyman portion:

1. First pass, about 3 minutes each. Answer every question you know how to set up. If you cannot see the method within a minute, write the question number on the notepad and move on.
2. Second pass. Go back to the numbers on your list. PSI lets you return to any question and change your answer while time remains.
3. Last 10 minutes. Make sure nothing is blank. The bulletin scores by percent correct and mentions no guessing penalty, so a blank can only cost you.

Leftover time does not carry into the next portion, so if you finish early, recheck the problems with the most steps.

Step 1: classify the question before you calculate

Read the last sentence first. It tells you what is being asked. Then name the type. Each type has a fixed method and a fixed place in the code book.

If the question asks for	It is a	Where to look	Drill
Amps, volts, ohms, watts of a circuit	Theory	No code lookup needed	Ohm’s law, series and parallel
Load of a dwelling, service or feeder size	Load calculation	Article 120 in the 2026 NEC	Dwelling standard load
Minimum conductor size	Conductor sizing	Ampacity table plus correction and adjustment	Conductor sizing, ampacity correction
Breaker or fuse size	OCPD sizing	Standard ampere ratings in Article 240	OCPD sizing
Motor conductors, protection or overloads	Motor circuit	Article 430 and its FLC tables	Motor branch circuit, motor OCPD
Number of wires in a box or conduit	Fill	Article 314 for boxes, Chapter 9 tables for conduit	Box fill, conduit fill
Voltage at the end of a run	Voltage drop	Chapter 9 conductor properties	Voltage drop
Transformer amps or protection	Transformer	Article 450	Transformer current, transformer protection
Grounding conductor size	Grounding	Article 250 tables	GEC sizing, EGC sizing

Once you know the type, the question shrinks to “plug the givens into a method I already know.”

Step 2: write the givens as a small table

On the electronic notepad, write the givens as a short list or table before you calculate. For a box fill problem that means each conductor size and how many, the devices, the clamps, the grounding conductors. For a dwelling load it means each load, its VA and the demand factor that applies. For a motor feeder it means each motor’s table current and which one is largest.

This takes 30 seconds and prevents the most common failure: dropping one item from a list of six.

Step 3: use the code book index, not your memory

The exam is open book, so you never need to recall a table value. You need to find it fast and read it correctly.

• Look up a plain keyword in the index (“box fill”, “motors, full-load current”, “dwelling, range demand”) and go straight to the section.
• Read the table title and footnotes before taking a number. Temperature columns, copper or aluminum, and the conditions in the notes change the answer.
• Highlight and tab your book ahead of time within PSI’s rules. See open-book NEC rules and tabs.
• The 2026 NEC moved dwelling load calculations into Article 120, per TDLR’s November 2026 newsletter. If you studied from a 2023 book, your old page memory for Article 220 no longer works. See 2026 NEC changes.

Practice this with our code lookup drills until each lookup takes under a minute.

Step 4: check against the common traps

Before you pick an answer, run through this list:

• Optional methods or exceptions used without being asked. PSI says not to.
• Aluminum used when nothing was said. Conductors are copper unless stated.
• Continuous loads not at 125%. A load running 3 hours or more is sized at 125% for conductors and protection. EV charging is treated as a continuous load.
• Motor nameplate amps used for conductors or breakers. The NEC has you use its full-load current tables for those, and the nameplate for overloads.
• Wrong ampacity column. Check the termination temperature rating, and only derate from the 90°C column when the insulation allows it.
• Three-phase without √3, or single-phase with it. Three-phase current is power divided by (voltage × 1.732).
• Voltage drop with the wrong multiplier. Single-phase uses 2 × length; three-phase uses 1.732 × length.
• Wrong voltage. 208 V and 240 V give different answers. Use the one in the question.
• Rounding at the wrong time. Keep full numbers until the last step, then round the way the question or the code says.
• Box fill count errors. All equipment grounding conductors together count once; each device yoke counts twice.

Our worked steps in every drill flag these traps where they apply. The formula sheet collects the formulas in one place.

Which drills match each outline area

The PSI bulletin lists scored items per area. Counts below are for the Journeyman (J) and Master (M) calculations portions.

Outline area	J	M	Drills
Calculations and theory	2	2	Ohm’s law, series-parallel, three-phase power, power factor and efficiency
Services (load calcs, grounding, transformers)	4	8	Dwelling standard, dwelling optional, multifamily optional, commercial lighting, receptacle load, GEC, transformer current, transformer protection
Feeders (load calcs, OCP)	3	3	Neutral load, OCPD sizing, kitchen equipment
Branch circuits and conductors	4	4	Conductor sizing, ampacity correction, voltage drop, continuous loads, EGC
Raceways and boxes	2	2	Box fill, conduit fill, pull box sizing
A/C and appliances	2	2	Appliance demand, range demand, dryer demand
Motors and generators	2	6	Motor FLC, motor branch circuit, motor OCPD, motor overloads, motor feeder
Controls and disconnecting means	1	1	No dedicated topic; the motor drills are closest
Special occupancies (RVs, mobile homes, data processing, marinas)	3	1	No dedicated topic; use code lookup
Renewable energy (EV, PV)	1	1	Continuous loads, conductor sizing

For master candidates, services and motors are 14 of 30 items. For journeyman candidates, services, feeders and branch circuits are 11 of 24. Start there.

A simple practice routine

1. Pick one topic. Work drills with the steps showing until you get 5 right in a row.
2. Hide the steps and time yourself. Target 4 minutes (journeyman) or 5 (master), code book open.
3. Once every topic passes step 2, run mixed timed sets on the journeyman or master practice test.
4. Log every miss by trap. If the same trap shows up three times, go back to that topic.

The drills generate new numbers every time, so you cannot memorize answers, only methods. That is the point.

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