EEI CAST and CAST-R study guide

Read drawings accurately, understand the mechanics and work confidently from technical information. Match your practice to the version in your invitation.

Choose a practice drill

Methods and worked examples

Start with the skills you find hardest. These teaching examples isolate one method; scored practice uses separate questions, drawings and passages.

Graphic arithmetic

Drawing dimensions

Trace the exact endpoints of each dimension line. Write a whole length as the sum of its non-overlapping parts, then find the missing part. Use the printed measurements rather than the apparent size of the picture.

Watch for: Adding overlapping measurements or using a center-to-center dimension as an edge-to-edge gap.

Practice drawing dimensions

Example

A straight run is 18 ft long. Its three consecutive, non-overlapping sections measure 7 ft, 4 ft and an unknown length. How long is the last section?

Solution: 7 ft. Subtract both known sections from the whole: 18 − 7 − 4 = 7. This works because the three sections exactly fill the measured run.

Drawing areas

Split the shape into rectangles or subtract a clearly defined cutout from the enclosing rectangle. Label the dimensions you use and keep square units separate from length units.

Watch for: Treating a missing corner as solid area, or subtracting a length from an area.

Practice drawing areas

Example

An L-shaped pad fits inside a 14 ft by 10 ft rectangle. The missing upper-right corner is 6 ft wide and 4 ft high. What is the pad’s area?

Solution: 116 ft². The enclosing rectangle has area 14 × 10 = 140 ft². The missing corner has area 6 × 4 = 24 ft². Subtract: 140 − 24 = 116 ft².

Mechanical concepts

Forces and motion

Identify the object and all relevant forces. For a balanced lever, compare force multiplied by perpendicular distance from the pivot. For motion, distinguish a net force from several forces that cancel.

Watch for: Comparing forces alone when their distances from the pivot differ.

Practice forces and motion

Example

An ideal, weightless horizontal lever has a 120 N downward load 0.5 m to the left of its pivot. What downward effort, applied 1.5 m to the right, balances it?

Solution: 40 N. The load produces 120 × 0.5 = 60 N·m of turning effect. The effort must produce the opposite 60 N·m, so effort = 60 ÷ 1.5 = 40 N.

Machines and mechanisms

Track direction and size separately. Meshing external gears turn in opposite directions; the smaller gear turns more times. For ideal pulleys, count the rope segments directly supporting the moving load.

Watch for: Keeping the same speed for gears with different tooth counts, or counting a rope segment that does not support the moving load.

Practice machines and mechanisms

Example

A 12-tooth external gear turns clockwise at 90 rpm and directly drives a 36-tooth external gear. What is the driven gear’s speed and direction?

Solution: 30 rpm counterclockwise. It has three times as many teeth, so it makes one turn for every three driver turns: 90 × 12 ÷ 36 = 30 rpm. The direct external mesh reverses direction.

Fluids and heat

State what is held constant. For a stationary liquid open to the same atmosphere, pressure above atmospheric pressure depends on liquid density and vertical depth. For heat flow, identify the temperature difference and the possible transfer route.

Watch for: Using the width of a container to predict pressure at a given depth.

Practice fluids and heat

Example

Two points in the same stationary water tank are 0.5 m and 1.5 m below the surface. How does the pressure above atmospheric pressure compare?

Solution: The deeper point has three times the pressure above atmospheric pressure: 1.5 ÷ 0.5 = 3. This compares gauge pressure, not total absolute pressure, and assumes the same liquid and surface pressure.

Electricity

First identify whether the path is open or closed and which components are in series or parallel. For a simple resistive DC circuit, apply current = voltage ÷ resistance with consistent units.

Watch for: Adding parallel resistances as though they were in series, or assuming a disconnected path still carries steady current.

Practice electricity

Example

An ideal 12 V DC supply is connected in a closed circuit to a single 6 Ω resistor. Ignoring wire resistance, what current flows?

Solution: 2 A. Current = 12 V ÷ 6 Ω = 2 A. The assumptions rule out additional resistance and an open circuit.

Reading for comprehension

Finding evidence

Read the question, locate the relevant part of the passage and check each part of the answer against it. Use only the provided text, including conditions and exceptions.

Watch for: Treating one necessary condition as enough on its own, or importing outside knowledge.

Practice finding evidence

Example

A passage says: “Only inspected reels may be loaded. Reels with damaged flanges are held for review. Intact flanges alone do not establish that inspection has occurred.” Can you conclude that a reel with intact flanges may be loaded?

Solution: No. Inspection is required, and intact flanges do not establish inspection. The passage does not give enough information to approve loading that reel.

Following procedures

Turn the text into a short sequence or conditional rule. Separate what must happen first from what happens only if a check fails. Find the rule that applies to the specific situation in the question.

Watch for: Skipping a required sign-off because an earlier check passed.

Practice following procedures

Example

A fictional procedure says: “After replacement, record the sensor’s serial number, run the check, then obtain supervisor release. A failed check must be investigated before release.” The serial number is recorded and the check passes. What is still required?

Solution: Supervisor release. Passing the check removes the failed-check investigation step, but does not remove the stated release requirement.

Mathematical usage · Original CAST

Conversions

Write the unit you need beside the unit you have. Choose a conversion factor that cancels the starting unit, and carry units through each step.

Watch for: Multiplying by a conversion factor when the direction requires dividing, or stopping after only one conversion.

Practice conversions

Example

Use this supplied reference: 1 ft = 12 in; 1 in = 2.54 cm. How many centimeters are in 2.5 ft?

Solution: 76.2 cm. First, 2.5 ft × 12 in/ft = 30 in. Then, 30 in × 2.54 cm/in = 76.2 cm.

Calculations

Identify the relevant reference or rule before calculating. Keep track of units, signs and the order of operations. For fractions, use a common denominator and simplify at the end.

Watch for: Adding denominators directly or rounding away a needed fraction.

Practice calculations

Example

Two marked lengths are 5/8 in and 3/4 in. Using 3/4 = 6/8, what is their combined length?

Solution: 11/8 in, or 1 3/8 in. With the common denominator, 5/8 + 6/8 = 11/8. The length is greater than 1 in, which is a useful reasonableness check.

Work from a dimensioned drawing

Use the measurements to calculate the remaining area. Do not estimate lengths from the picture.

What is the area of this work pad?

Use the printed dimensions. The upper-right corner is missing.

Original teaching example. Dimensions in feet; do not measure the picture.

Check whether you need CAST or CAST-R

Original CAST and CAST-R share three aptitude sections. Original CAST adds Mathematical Usage; CAST-R instead adds the Work Preferences Inventory. A generic “CAST” label alone may not identify the version.

Published section counts and time limits
Section	Original CAST	CAST-R
Graphic Arithmetic	16 questions / 30 minutes	16 questions / 30 minutes
Mechanical Concepts	44 questions / 20 minutes	44 questions / 20 minutes
Reading for Comprehension	32 questions / 30 minutes	32 questions / 30 minutes
Mathematical Usage	18 questions / 7 minutes	Not included
Work Preferences Inventory	Not included	105 responses / 30 minutes

Original CAST totals 110 aptitude questions and 87 minutes of section time. CAST-R has 92 aptitude questions in 80 minutes, plus the separate 30-minute inventory. Instructions and administration add time to the actual session. Sources: EEI’s original CAST brochure and CAST-R student guide.

Choose original CAST full practice for all four aptitude subjects, or CAST-R aptitude practice for the three revised aptitude subjects. The 80-minute mode does not include a scored inventory. Use the free Work Preferences orientation separately.

Why are official practice samples shorter?

The EEI CAST-R sample PDF contains shortened examples: eight graphic questions, 26 mechanical questions and 24 reading questions, with shorter suggested clocks. Those samples introduce the tasks; they are not the full-test blueprint. Our longer practice follows the brochure’s section counts and limits while using original content.

Use the right tools and section clocks

EEI’s current original CAST brochure permits a calculator in Graphic Arithmetic and Mathematical Usage. The revised guide permits one in Graphic Arithmetic. Our matching sections and drills include a calculator. Your employer controls the actual calculator model, supplied tools and testing setup.

Read the provided reference. Mathematical Usage practice keeps the relevant mathematical information available. Choose the right conversion or rule before calculating.
Review within the current section. In our timed practice, you can move between its questions, flag uncertain answers and revise them before the section ends.
Finish sections deliberately. Confirming a section or reaching its deadline locks it. Unused time does not transfer to the next section.
Keep the clock in mind. Timed practice continues while the tab is hidden or the page reloads. The next section begins when the previous one expires.
Read the source again when needed. Drawings and passages remain available beside their questions. Do not rely on memory of a dimension or a conditional instruction.

These navigation and countdown controls describe our practice. Actual administration can differ, including paper or online delivery and approved adjustments. Follow your invitation and administrator’s instructions.

Understand your practice results

Timed tests show results only after the entire selected test ends. Mechanical and math drills let you check each answer. A drawing or reading drill holds explanations until all eight questions in its shared set are finished.

Review accuracy, unanswered questions, section timing and the explanation for each choice. Unanswered and unreached questions remain in the planned total. A high score on the questions you reached does not hide a section you could not finish.

EEI describes an index from 1 to 10, but its public brochures do not provide a scoring conversion for our original questions. Your practice percentage is not that index, an employer pass mark or a hiring prediction.

Use the employer’s preparation guidance

Different utilities and roles can use different assessments. Use the exact name in your invitation, then follow the employer’s current preparation links.

Southern Company

Its hiring page specifically names CAST-R and distinguishes the aptitude practice from Work Preferences preparation.

Read employer guidance

Ameren apprenticeships

Its Illinois and Missouri skilled-craft guidance explicitly names CAST-R. Individual apprenticeship tracks and invitations still control the required tests.

Read employer guidance

PSEG

Its page maps CAST to examples of skilled-trade roles and provides test-preparation resources. Do not assume every PSEG application takes the same battery.

Read employer guidance

Entergy

Its testing page lists CAST among several EEI assessments. The job and invitation determine which battery you need; generic CAST wording does not confirm a revised version.

Read employer guidance

EEI explains that employers administer employment tests and provide the results. This practice site does not register you for an official assessment.

Approach Work Preferences honestly

CAST-R’s inventory asks how much you agree with statements about work styles, behavior and environments. It is different from a mechanical problem with a factual correct answer. Think about your usual behavior and use the response scale as written.

Our free orientation uses a few original rating examples. It explains how to respond without assigning a personality score, storing your ratings or suggesting an ideal utility-worker profile.

Try the Work Preferences examples

Build accuracy, then test your pace

Confirm the version. Include Mathematical Usage only if your test requires it. Add Work Preferences orientation if your invitation names the inventory.
Start with short drills. Explain each drawing, rule or calculation in your own words. Separate a misunderstood concept from a simple arithmetic mistake.
Practice one timed section. Check whether you can maintain accuracy across the full number of questions. Reading and drawing questions require sustained attention to shared material.
Use fresh material. Practice selection prefers unseen groups while available. Familiar drawings, passages or questions are useful rehearsal, but are not independent evidence of improvement.
Take the matching longer form. Review the weakest section first afterward. A strong subject should not hide a subject that needs more work.

Our demanding editorial goal is at least 90% correct overall, in every section and on its planned Challenge questions, with every question answered within the relevant clocks. Fractional targets round up; an eight-question drill requires eight correct answers. Build consistency across three different comparable sets.

These are learning targets, not official EEI cutoffs. Our original question difficulty has not been equated to the employer’s assessment.

Other trade assessments

If your invitation names a different test, choose that preparation instead. These are separate products with their own passes.

IBEW apprenticeship Elevator aptitude Bennett mechanical WorkKeys

Choose your next practice

One EEI CAST / CAST-R pass covers both aptitude forms, all four timed subject tests and drill replays. Work Preferences orientation remains free.

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Original independent preparation. Not affiliated with or endorsed by EEI or the employers named. Source guidance checked September 2026; follow your current invitation.