Free CAST Practice Test: 4 Real Questions Explained

The CAST test — the Construction and Skilled Trades Selection System used by electric utilities to hire line workers, electricians, and other skilled-trades apprentices — trips people up less on raw math ability and more on speed and trap answers. Here are four real practice questions, worked step by step, so you can see exactly how the test tries to catch you.

These questions are drawn from the same style tested in CertPath Publishing's CAST Exam Study Guide, which also unlocks a free set of 25 tough CAST practice questions online at certpathpublishing.store/sample?book=cast — no email or signup required, with a full explanation after every answer. Below, we'll walk through four of them (two Mathematical Usage, two Reading for Comprehension) in detail, then cover what the real exam actually looks like.

What the CAST test actually covers

CAST is developed by the Edison Electric Institute (EEI), the trade association of investor-owned electric utility companies, and is used across the industry to screen applicants for line worker, electrician, and other construction and skilled-trades positions. CertPath Publishing is an independent publisher and is not affiliated with or endorsed by EEI.

The test has 110 scored questions split across four timed sections, for roughly 87 minutes of total testing time. No calculator is allowed on any section:

• Graphic Arithmetic — 16 questions, 30 minutes. Reading dimensions and quantities off a print or drawing and doing the math.
• Mathematical Usage — 18 questions, 7 minutes. Word problems solved with basic arithmetic, ratios, and rates — the tightest time limit on the test.
• Mechanical Concepts — 44 questions, 20 minutes. Gears, levers, pulleys, and basic physical reasoning.
• Reading for Comprehension — 32 questions, 30 minutes. Applying a written rule or procedure to a specific scenario.

Scores from all four sections combine into a single index score from 1 to 10 — there's no simple pass/fail cutoff published by EEI, and each hiring utility sets its own minimum score for the roles it's filling. CAST also isn't something you register for directly through EEI; it's administered by the utility as part of its own hiring process, so the exact scheduling, retake window, and score requirement depend on the employer you're applying to.

Question 1: Mathematical Usage — rate changes mid-task

A transformer oil reservoir holds 275 gallons and is 60 % full. A transfer pump moves 12 quarts per minute for the first 20 minutes; a strainer then partly plugs and the rate falls to 9 quarts per minute for the rest of the job. How long does it take to move all of the oil that is in the reservoir, to the nearest minute?

• A. 73 minutes
• B. 55 minutes
• C. 116 minutes
• D. 67 minutes

Correct answer: D — 67 minutes.

Explanation: The oil in the reservoir is 275 × 0.60 = 165 gallons, or 660 quarts. In the first 20 minutes, the pump moves 20 × 12 = 240 quarts, leaving 420 quarts once the strainer plugs. At the slower rate of 9 quarts per minute, that remaining oil takes 420 ÷ 9 = 46.7 minutes, so the total time is 20 + 46.7 = 66.7 minutes, which rounds to 67.

Skill tested: multi-step rate problems where the rate itself changes partway through — a Mathematical Usage staple.

The trap: answer B (55 minutes) comes from running the whole job at 12 quarts per minute and ignoring the strainer slowdown entirely. Answer A (73 minutes) makes the opposite mistake and runs the whole job at the slower 9-quart rate. Answer C (116 minutes) empties the full 275-gallon tank instead of just the 60% that's actually in it. Each wrong answer represents one specific, predictable slip — not a random distractor.

Question 2: Mathematical Usage — working backward from a deadline

One line crew sets 18 poles in 5 working days. A hardening job needs 80 poles set within an 8-working-day window, but weather is expected to cost every crew one full day out of those 8. If all crews work at the same rate, what is the smallest number of crews that still finishes inside the window?

• A. 4 crews
• B. 2 crews
• C. 3 crews
• D. 5 crews

Correct answer: A — 4 crews.

Explanation: One crew sets 18 ÷ 5 = 3.6 poles per day. Weather leaves 7 usable working days out of the original 8, so one crew can set 3.6 × 7 = 25.2 poles in that window. Since 80 ÷ 25.2 = 3.17, three crews would fall short, so the job needs 4 crews to guarantee it's finished inside the window.

Skill tested: converting a rate, then applying a constraint (the lost weather day) before dividing to find a crew count — and remembering to round up, not to the nearest whole number.

The trap: answer C (3 crews) comes from using all 8 days instead of the 7 that are actually usable after weather. Answer D (5 crews) comes from dividing 80 by 18 directly and rounding up without ever computing a daily rate. Answer B (2 crews) only accounts for 50.4 poles in the usable window — well short of 80.

Question 3: Reading for Comprehension — applying two rules at once

Read this excerpt from a utility work rule. "Work on a de-energized circuit is authorized by a clearance issued to one named holder. The holder confirms the switching order is complete, sees protective grounds installed at the work site, and signs the crew on. A holder leaving the site transfers the clearance in person to a relief holder; a clearance is never left with a crew and no holder present. Grounds are moved only with the holder present, and every move is logged with its time. When work is finished the holder removes the crew, then the grounds, then reports clear to the system operator, who alone re-energizes. If a crew must work at a structure outside the grounded section, the operator extends the clearance and grounds are installed there first." Late in the day the holder must drive to another job while the crew keeps working, and the crew also needs to work two spans beyond the existing grounds. Which plan follows the rule?

• A. Hand the clearance to a relief holder in person, then have the operator extend it and ground the new structure before work starts there.
• B. Report clear so the operator can re-energize, then take a fresh clearance when the crew reaches the second structure.
• C. Keep the clearance open and have the crew work the two spans while staying inside the section already grounded.
• D. Leave the clearance with the crew foreman, then move the existing grounds two spans out and log the time of the move.

Correct answer: A.

Explanation: Two separate rules apply at the same time here. A holder who leaves the site must hand the clearance to a relief holder in person — never leave it with the crew. And work outside the already-grounded section requires the operator to extend the clearance and new grounds to go in first. Only answer A satisfies both requirements together.

Skill tested: holding two independent conditions in mind at once and picking the one answer that satisfies both, instead of an answer that only handles one of them.

The trap: answer D is the strongest distractor, because the rule does allow grounds to be moved — but only with a holder present, and here the holder has already left, so moving grounds without them breaks the rule. Answer C ignores that the crew needs to work outside the grounded section at all. Answer B invents a step (re-energizing and re-clearing) that the passage never describes as necessary.

Question 4: Reading for Comprehension — priority rules that override the default order

Read this excerpt from a storm plan. "Restoration is worked in stages: sources first, then main feeders, then branch lines, then services. Within a stage, crews take the work that restores the most customers per crew-hour. Two rules override that order. Wires down where the public can reach them are made safe whenever they are reported. And a circuit carrying a hospital, water plant or lift station within its first mile is restored ahead of other circuits in the same stage, even where another circuit would restore more customers. Crews are not moved from one stage to the next while a stage is incomplete, unless the control center closes the stage, which it does only when the work left in it needs equipment that is not on site." A crew working main feeders is offered a branch line that restores 400 customers, a feeder with a water plant in its first mile that restores 90, and a second feeder that restores 250. No wires are down. What does the plan direct?

• A. Take the branch line restoring 400 customers, because it returns the most of the three.
• B. Take the feeder restoring 250 customers, because it returns the most in this stage.
• C. Take the feeder with the water plant, because that rule outranks customers per crew-hour.
• D. Ask the control center to close the feeder stage so the branch line can be taken.

Correct answer: C.

Explanation: Two of the three jobs offered are feeders, which matches the stage the crew is already in. Between those two, the water-plant override rule decides the choice regardless of what the customer counts say, so the crew takes the water-plant feeder even though it restores fewer customers than the alternative.

Skill tested: recognizing when a stated override rule beats the normal decision rule (customers per crew-hour), rather than defaulting to the biggest number.

The trap: answer B is the strongest distractor because "most customers per crew-hour within a stage" is genuinely the normal rule — it's just beaten here by the water-plant override. Answer A picks the single biggest number in the list without checking that the branch line belongs to a later stage the crew hasn't reached yet. Answer D invents a way around the stage order that the passage doesn't support — a stage is only closed for missing equipment, not to reach preferred work early.

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CertPath Publishing's CAST Exam Study Guide pairs the strategy above with 3 full-length timed practice tests (330 questions total) and a step-by-step explanation for every question.

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What these four questions tell you about the real test

Notice that in all four questions, the wrong answers aren't random — each one is the exact result of one specific, predictable mistake (using the wrong time window, forgetting to round up, missing one of two rules, picking the biggest number instead of the right one). That's how CAST question writers build distractors across every section, not just these two. The fastest way to raise your score isn't memorizing formulas; it's training yourself to notice which trap each wrong answer represents before you pick.

The other pattern worth noticing: Mathematical Usage gives you roughly 23 seconds per question, which is why mental math and quick estimation matter more than long-hand arithmetic. Reading for Comprehension gives you almost a full minute per question, but the passages pack in two or three conditions you have to track simultaneously — slow down and underline the override rules rather than rushing.

The remaining 21 questions in the free set cover Graphic Arithmetic and Mechanical Concepts as well, worked the same way with a full explanation after each one. Head to the free CAST sample to try them.

FAQ

Where can I find free CAST practice questions?

CertPath Publishing has 25 free CAST practice questions at certpathpublishing.store/sample?book=cast. No email or signup is required, and you get a full explanation after every answer.

How many questions are on the real CAST test?

The CAST test has 110 scored questions across four timed sections — Graphic Arithmetic, Mathematical Usage, Mechanical Concepts, and Reading for Comprehension — completed in about 87 minutes of timed testing.

Can I use a calculator on the CAST test?

No. The Mathematical Usage and Graphic Arithmetic sections are completed without a calculator, so being comfortable with mental math and quick estimation under a tight time limit matters more than knowing advanced formulas.

Is CAST pass or fail?

Not exactly. The four sections combine into a single index score from 1 to 10. Each hiring utility sets its own minimum score for the role it's filling, so there's no single passing score published by EEI.

Can I retake the CAST test if I don't score well?

Retake rules are set by the hiring utility, not by one EEI-wide policy. Many employers require a waiting period of roughly two to four weeks and limit candidates to a small number of attempts within a 12-month period — check the specific job posting or ask the recruiter for that employer's exact policy.

For the full study guide with all three timed practice tests, see the CAST exam page or buy the CAST Exam Study Guide on Amazon. And if CAST isn't the exam you're studying for, CertPath has free practice for other exams here.

— The CertPath Publishing Team